XML 67 R52.htm IDEA: XBRL DOCUMENT v3.10.0.1
STOCK-BASED COMPENSATION AND EMPLOYEE BENEFIT PLANS - Stock Option and Restricted Stock Plans (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 12 Months Ended
Mar. 31, 2018
Dec. 31, 2018
Mar. 31, 2018
Dec. 31, 2017
Mar. 31, 2017
Dec. 31, 2016
Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Share based compensation, shares authorized (in shares)   15,825,223          
Share based compensation, shares authorized for future grant (in shares)   3,482,300          
Intrinsic value of nonvested restricted stock awards expected to vest   $ 10,100          
Unrecognized compensation related to non-vested awards   $ 8,200          
Unrecognized compensation costs, weighted average period expected to be recognized (years)   2 years          
Proceeds from employee common stock purchases   $ 1,382   $ 1,330   $ 1,114  
Service-based Restricted Shares              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Share based compensation, award shares granted in period (in shares)   404,638          
Forfeited shares (in shares)   32,862          
Share based compensation, fair value of restricted stock vested   $ 5,100   $ 4,700   $ 4,600  
Granted (in usd per share)   $ 14.15   $ 21.46   $ 17.67  
Performance- based Restricted Shares              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Share based compensation, award shares granted in period (in shares)   177,730          
Share based compensation, annual award vesting period from date of grant   3 years   3 years   3 years  
Forfeited shares (in shares)   91,820          
Share based compensation, fair value of restricted stock vested   $ 0   $ 1,200   $ 1,600  
Granted (in usd per share)   $ 13.70   $ 22.00   $ 17.62  
Performance Period 2016 to 2018 | Performance- based Restricted Shares              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Share based compensation, award shares earned in period (in shares)   64,846          
Share based compensation, dividend earned on shares subject to the awards (in shares)   4,226          
Forfeited shares (in shares)   73,345          
Performance Period 2015 to 2017 | Performance- based Restricted Shares              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Forfeited shares (in shares)       91,820      
Performance period 2014 to 2016 | Performance- based Restricted Shares              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Share based compensation, award shares earned in period (in shares)           59,437  
Share based compensation, dividend earned on shares subject to the awards (in shares)           4,945  
Forfeited shares (in shares)           21,503  
Employees and executives | Service based awards | Service-based Restricted Shares              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Share based compensation, award shares granted in period (in shares)   350,054          
Share based compensation, award granted in period grant-date fair value   $ 4,900          
Share based compensation, annual award vesting period from date of grant   1 year          
Employees and executives | Service based awards | Service-based Restricted Shares | Share-based Compensation Award, Tranche One              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Share based compensation, award annual installment vesting rate   25.00%          
Employees and executives | Performance based awards | Service-based Restricted Shares              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Share based compensation, award shares granted in period (in shares) 177,730            
Share based compensation, award granted in period grant-date fair value $ 2,400            
Share based compensation, annual award vesting period from date of grant 3 years            
Non employee directors | Service based awards | Service-based Restricted Shares              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Share based compensation, award shares granted in period (in shares)   54,584          
Share based compensation, award granted in period grant-date fair value   $ 800          
Share based compensation, annual award vesting period from date of grant   1 year          
Employee stock              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Share based compensation, shares authorized (in shares)   2,321,688          
Proceeds from employee common stock purchases     $ 1,400   $ 1,300   $ 1,100