Annual report pursuant to Section 13 and 15(d)

CAPITAL TRANSACTIONS (Details 2)

v2.4.1.9
CAPITAL TRANSACTIONS (Details 2) (USD $)
In Thousands, except Share data, unless otherwise specified
0 Months Ended 12 Months Ended 1 Months Ended
Sep. 19, 2014
Aug. 29, 2013
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Jan. 31, 2015
Stock options            
Number of shares            
Options outstanding at the beginning of the period (in shares)     1,926,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
1,784,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
1,374,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
 
Granted (in shares)     258,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
832,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
686,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
 
Forfeited or canceled (in shares)     (23,000)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
(184,000)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
(35,000)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
 
Exercised (in shares)     (124,000)us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
(506,000)us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
(241,000)us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
 
Options outstanding at the end of the period (in shares)     2,037,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
1,926,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
1,784,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
 
Weighted Average Exercise Price Per Share            
Options outstanding at the beginning of the period (in dollars per share)     $ 12.54us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
$ 11.81us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
$ 9.88us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
 
Granted (in dollars per share)     $ 15.38us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
$ 15.85us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
$ 15.11us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
 
Forfeited or canceled (in dollars per share)     $ 13.33us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
$ 13.65us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
$ 13.60us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
 
Exercised (in dollars per share)     $ 6.42us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
$ 8.56us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
$ 9.95us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
 
Options outstanding at the end of the period (in dollars per share)     $ 11.69us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
$ 12.54us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
$ 11.81us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
 
Share-based compensation, additional disclosures            
Special one-time cash dividend paid per common share (in dollars per share) $ 1.50natr_SpecialOneTimeCommonStockDividendsPerShareCashPaid
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
$ 1.50natr_SpecialOneTimeCommonStockDividendsPerShareCashPaid
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
       
Decrease in exercise price of all outstanding stock options (in dollars per share)     $ 1.50natr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIncreaseDecreaseInExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
$ 1.50natr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIncreaseDecreaseInExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
   
Aggregate intrinsic values of options exercised     $ 1,093us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
$ 4,576us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
$ 1,427us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
 
Weighted-average assumptions used to calculate fair value of options granted            
Weighted-average grant date fair value (in dollars per share)     $ 6.53us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
$ 6.55us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
$ 7.21us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
 
Share-based compensation, related information            
Share-based compensation expense     0us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
     
Related tax benefit     307us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
653us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
378us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
 
Stock options | Maximum            
Weighted-average assumptions used to calculate fair value of options granted            
Expected life     6 years 6 years 6 years  
Risk-free interest rate (as a percent)     1.50%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
1.50%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
0.90%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
 
Expected volatility (as a percent)     56.70%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
58.20%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
66.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
 
Dividend yield (as a percent)     2.60%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
2.70%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
1.30%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
 
Stock options | Minimum            
Weighted-average assumptions used to calculate fair value of options granted            
Expected life       5 years 4 years  
Risk-free interest rate (as a percent)       0.60%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
0.30%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
 
Expected volatility (as a percent)       55.90%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
58.50%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
 
Dividend yield (as a percent)       2.10%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
0.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
 
Time-based stock options            
Share-based compensation, related information            
Share-based compensation expense     2,932us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_AwardTypeAxis
= natr_TimeBasedStockOptionsMember
3,166us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_AwardTypeAxis
= natr_TimeBasedStockOptionsMember
2,101us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_AwardTypeAxis
= natr_TimeBasedStockOptionsMember
 
Related tax benefit     1,158us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense
/ us-gaap_AwardTypeAxis
= natr_TimeBasedStockOptionsMember
1,251us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense
/ us-gaap_AwardTypeAxis
= natr_TimeBasedStockOptionsMember
850us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense
/ us-gaap_AwardTypeAxis
= natr_TimeBasedStockOptionsMember
 
Unrecognized share-based compensation expense     2,018us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
/ us-gaap_AwardTypeAxis
= natr_TimeBasedStockOptionsMember
3,294us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
/ us-gaap_AwardTypeAxis
= natr_TimeBasedStockOptionsMember
2,715us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
/ us-gaap_AwardTypeAxis
= natr_TimeBasedStockOptionsMember
 
Weighted-average period over which the remaining compensation cost is expected to be recognized     1 year 9 months 18 days      
Time-based stock options | Maximum            
Share-based compensation, additional disclosures            
Vesting period     48 months      
Performance based stock options operating income margins            
Share-based compensation, additional disclosures            
Operating income margin, one (as a percent)     6.00%natr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOperatingMarginsOne
/ us-gaap_AwardTypeAxis
= natr_PerformanceBasedStockOptionsVestingUponAchievingOperatingIncomeMarginsMember
     
Operating income margin, two (as a percent)     8.00%natr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOperatingMarginsTwo
/ us-gaap_AwardTypeAxis
= natr_PerformanceBasedStockOptionsVestingUponAchievingOperatingIncomeMarginsMember
     
Operating income margin, three (as a percent)     10.00%natr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOperatingMarginsThree
/ us-gaap_AwardTypeAxis
= natr_PerformanceBasedStockOptionsVestingUponAchievingOperatingIncomeMarginsMember
     
Period of time during which operating income margins must be achieved in order to vest in performance based stock options     12 months      
Consecutive period of time used to assess operating income margins which determine vesting     15 months      
Share-based compensation, related information            
Share-based compensation expense     0us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_AwardTypeAxis
= natr_PerformanceBasedStockOptionsVestingUponAchievingOperatingIncomeMarginsMember
0us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_AwardTypeAxis
= natr_PerformanceBasedStockOptionsVestingUponAchievingOperatingIncomeMarginsMember
653us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_AwardTypeAxis
= natr_PerformanceBasedStockOptionsVestingUponAchievingOperatingIncomeMarginsMember
 
Related tax benefit     0us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense
/ us-gaap_AwardTypeAxis
= natr_PerformanceBasedStockOptionsVestingUponAchievingOperatingIncomeMarginsMember
0us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense
/ us-gaap_AwardTypeAxis
= natr_PerformanceBasedStockOptionsVestingUponAchievingOperatingIncomeMarginsMember
255us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense
/ us-gaap_AwardTypeAxis
= natr_PerformanceBasedStockOptionsVestingUponAchievingOperatingIncomeMarginsMember
 
Unrecognized share-based compensation expense         $ 0us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
/ us-gaap_AwardTypeAxis
= natr_PerformanceBasedStockOptionsVestingUponAchievingOperatingIncomeMarginsMember
 
Performance based stock options sales and operating income margins            
Share-based compensation, additional disclosures            
Vesting period     2 years      
Operating income margin, two (as a percent)     8.00%natr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOperatingMarginsTwo
/ us-gaap_AwardTypeAxis
= natr_PerformanceBasedStockOptionsVestingUponAchievingSalesAndOperatingIncomeMarginsMember
     
Performance based stock options sales and operating income margins | Minimum            
Share-based compensation, additional disclosures            
Operating income margin, two (as a percent)     8.00%natr_ShareBasedCompensationArrangementByShareBasedPaymentAwardOperatingMarginsTwo
/ us-gaap_AwardTypeAxis
= natr_PerformanceBasedStockOptionsVestingUponAchievingSalesAndOperatingIncomeMarginsMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
     
Performance based stock options sales            
Share-based compensation, additional disclosures            
Vesting period based on achieving annual net sales targets     1 year      
2012 Stock Incentive Plan            
Share Based Compensation            
Number of shares authorized under the plan     1,500,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
/ us-gaap_PlanNameAxis
= natr_IncentivePlan2012Member
     
2012 Stock Incentive Plan | Subsequent event            
Share Based Compensation            
Additional number of shares authorized under the plan           1,500,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized
/ us-gaap_PlanNameAxis
= natr_IncentivePlan2012Member
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
2012 Stock Incentive Plan | Stock options            
Number of shares            
Granted (in shares)       832,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= natr_IncentivePlan2012Member
469,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= natr_IncentivePlan2012Member
 
Weighted Average Exercise Price Per Share            
Granted (in dollars per share)       $ 15.85us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= natr_IncentivePlan2012Member
$ 14.86us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= natr_IncentivePlan2012Member
 
Share-based compensation, additional disclosures            
Expiration period       10 years 10 years  
Weighted-average assumptions used to calculate fair value of options granted            
Weighted-average grant date fair value (in dollars per share)       $ 6.55us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= natr_IncentivePlan2012Member
$ 7.00us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= natr_IncentivePlan2012Member
 
2012 Stock Incentive Plan | Time-based stock options            
Number of shares            
Granted (in shares)     258us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= natr_TimeBasedStockOptionsMember
/ us-gaap_PlanNameAxis
= natr_IncentivePlan2012Member
     
Weighted Average Exercise Price Per Share            
Granted (in dollars per share)     $ 15.38us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= natr_TimeBasedStockOptionsMember
/ us-gaap_PlanNameAxis
= natr_IncentivePlan2012Member
     
Share-based compensation, additional disclosures            
Expiration period     10 years      
Weighted-average assumptions used to calculate fair value of options granted            
Weighted-average grant date fair value (in dollars per share)     $ 6.53us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= natr_TimeBasedStockOptionsMember
/ us-gaap_PlanNameAxis
= natr_IncentivePlan2012Member
     
2009 Incentive Plan            
Share Based Compensation            
Number of shares authorized under the plan     400,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
/ us-gaap_PlanNameAxis
= natr_IncentivePlan2009Member
     
2009 Incentive Plan | Time-based stock options            
Number of shares            
Granted (in shares)         217,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= natr_TimeBasedStockOptionsMember
/ us-gaap_PlanNameAxis
= natr_IncentivePlan2009Member
 
Weighted Average Exercise Price Per Share            
Granted (in dollars per share)         $ 15.65us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
/ us-gaap_AwardTypeAxis
= natr_TimeBasedStockOptionsMember
/ us-gaap_PlanNameAxis
= natr_IncentivePlan2009Member
 
Share-based compensation, additional disclosures            
Expiration period         10 years  
Weighted-average assumptions used to calculate fair value of options granted            
Weighted-average grant date fair value (in dollars per share)         $ 7.66us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= natr_TimeBasedStockOptionsMember
/ us-gaap_PlanNameAxis
= natr_IncentivePlan2009Member