XML 68 R56.htm IDEA: XBRL DOCUMENT v3.6.0.2
Stock-Based Compensation (Stock Options) - Additional Information (Detail) - USD ($)
shares in Millions, $ in Millions
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Compensation cost related to non-vested stock options not yet recognized $ 16.4    
Recognition period of non-vested compensation cost 2 years 10 months 24 days    
Share-based Compensation Arrangement by Share-based Payment Award, Options Outstanding, Weighted Average Exercise Price, and Additional Disclosures [Abstract]      
Number of shares available for grant 5.6    
Total pre-tax intrinsic value of options exercised $ 1.1 $ 0.1 $ 0.7
Fair value of options fully vested 5.7 $ 6.6 $ 7.7
Non Vested Stock Options [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Compensation cost related to non-vested stock options not yet recognized $ 7.5    
Recognition period of non-vested compensation cost 2 years 1 month 6 days