XML 142 R129.htm IDEA: XBRL DOCUMENT v3.8.0.1
Stock-Based Compensation Plans Compensation Costs from Equity Awards (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]      
Compensation costs from the Company's stock-based awards $ 17,477 $ 17,888 $ 14,301
Income tax benefit recognized 4,908 4,578 4,186
Employee Service Share-based Compensation, Tax Benefit from Exercise of Stock Options 2,546 $ 2,214 $ 4,079
Compensation costs related to non-vested awards not yet recognized $ 21,100    
Period over which non-vested awards will be recognized 3 years    
Weighted average period over which non-vested awards will be recognized 1 year 7 months 6 days