XML 79 R61.htm IDEA: XBRL DOCUMENT v3.6.0.2
Stock-Based Compensation - Summary of Award Information (Details) - Restricted Stock - $ / shares
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]      
Beginning balance (in shares) 827,950 543,707 541,180
Granted (in shares) 489,826 629,504 281,491
Vested (in shares) (430,597) (335,544) (275,051)
Canceled (in shares) 0 (9,717) (3,913)
Ending balance (in shares) 887,179 827,950 543,707
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]      
Beginning balance (in dollars per share) $ 28.92 $ 26.43 $ 19.98
Granted (in dollars per share) 30.95 29.01 29.38
Vested (in dollars per share) 26.75 24.80 16.83
Canceled (in dollars per share) 0.00 38.17 20.44
Ending balance (in dollars per share) $ 31.09 $ 28.92 $ 26.43