Quarterly report pursuant to Section 13 or 15(d)

Capital Transactions (Details)

v3.8.0.1
Capital Transactions (Details) - USD ($)
$ / shares in Units, $ in Thousands
 1 Months Ended 3 Months Ended
Jan. 31, 2015
Mar. 31, 2018
Mar. 31, 2017
Dec. 31, 2017
Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Options to purchase (in shares)   1,295,000   1,390,000  
Exercised (in shares)   30,000      
Exercised (in dollars per share)   $ 5.88      
Stock option activity (in shares)     0    
Stock options          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Options to purchase (in shares)   1,295,000   1,390,000  
Aggregate Intrinsic value, outstanding   $ 700   $ 900  
Exercisable (in shares)       1,293,000  
Expected to vest (in shares)       92,000  
Aggregate Intrinsic value, exercisable       $ 900  
Aggregate Intrinsic value, expected to vest       0  
Exercised (in shares)   30,000      
Exercised (in dollars per share)   $ 5.88      
Aggregate intrinsic values of options exercised   $ 200      
Tax benefit from the exercise of stock options   32      
Time-based stock options          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Share-based compensation expense   13 $ 100    
Unrecognized share-based compensation expense   $ 0   $ 13  
Time-based stock options | Maximum          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vesting period   48 months      
Performance based stock options operating income margins          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Operating income margin, one (as a percent)   6.00%      
Operating income margin, two (as a percent)   8.00%      
Operating income margin, three (as a percent)   10.00%      
Performance Shares          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Unvested options outstanding (in shares)   0   0  
2012 Stock Incentive Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Number of shares authorized under the plan (in shares)         1,500,000
Additional number of shares authorized under the plan (in shares) 1,500,000        
2009 Incentive Plan | Maximum          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Number of shares authorized under the plan (in shares)   400,000