XML 75 R61.htm IDEA: XBRL DOCUMENT v3.8.0.1
STOCK-BASED COMPENSATION PLANS (Details) - Equity Incentive Plan - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Stock-based Compensation      
Shares authorized to be issued under the plan (in shares) 2,000,000    
Compensation expense      
Recorded compensation costs for the RSAs and RSUs $ 3.1 $ 2.8 $ 2.9
Restricted Stock Awards (RSAs)      
Stock-based Compensation      
Awards granted (in shares) 49,290 72,317  
Awards cancelled (in shares) 20,747 16,617  
Weighted average grant date fair value (in dollars per share) $ 36.75 $ 25.17  
Restricted Stock Awards (RSAs) | Director      
Stock-based Compensation      
Vesting period   12 months  
Restricted Stock Awards (RSAs) | Employees      
Stock-based Compensation      
Vesting period   36 months  
Performance-Based Restricted Stock Unit Awards (RSUs) [Member]      
Stock-based Compensation      
Expiration period of award 3 years    
Performance-Based Restricted Stock Unit Awards (RSUs) [Member] | Officer      
Stock-based Compensation      
Awards granted (in shares) 31,389 43,659  
Weighted average grant date fair value (in dollars per share) $ 36.75 $ 25.17  
Performance-Based Restricted Stock Unit Awards (RSUs) [Member] | Officer | Minimum      
Stock-based Compensation      
Options vested on anniversary date (as a percent) 0.00%    
Performance-Based Restricted Stock Unit Awards (RSUs) [Member] | Officer | Maximum      
Stock-based Compensation      
Options vested on anniversary date (as a percent) 200.00%    
Restricted Stock Unit Award (RSUs) | Officer      
Stock-based Compensation      
Awards granted (in shares) 38,709    
Awards cancelled (in shares) 19,735 6,602  
Shares issued (in shares)   28,424