Annual report pursuant to Section 13 and 15(d)

EMPLOYEE BENEFIT PLANS (Details)

v3.10.0.1
EMPLOYEE BENEFIT PLANS (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
401(k) plans      
Employer's matching contribution (as a percent) 70.00%   70.00%
Maximum contribution by employer as a percentage of employee's compensation 5.00%   5.00%
Employer's matching contribution before change (as a percent)     60.00%
Vesting period of employer's contributions 3 years    
Contributions by employer $ 1.0 $ 1.1 $ 1.1
Nonqualified deferred compensation plan      
Maximum percentage of annual salary and bonus that may be deferred 100.00%    
Period for payment of obligation upon separation, one 3 years    
Period for payment of obligation upon separation, two 5 years    
Deferred compensation plan assets $ 1.3 $ 2.0