Annual report pursuant to Section 13 and 15(d)

Share-based Compensation - Summary of Transactions for Non-Vested Stock Options (Detail)

v3.10.0.1
Share-based Compensation - Summary of Transactions for Non-Vested Stock Options (Detail) - 2007 and 2013 Plan - $ / shares
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]      
Number of Shares, Non-vested options outstanding at beginning of period (shares) 9,335 46,340 176,688
Number of Shares, Options vested (shares) (9,335) (37,005) (130,223)
Number of Shares, Options forfeited (shares) 0 0 (125)
Number of Shares, Non-vested options outstanding at end of period (shares) 0 9,335 46,340
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]      
Weighted-Average Exercise Price Per Share, Non-vested options outstanding at beginning of period (in usd per share) $ 23.47 $ 22.42 $ 19.13
Weighted-Average Exercise Price Per Share, Options vested (in usd per share) 23.47 22.16 17.83
Weighted-Average Exercise Price Per Share, Options forfeited (in usd per share) 0.00 0.00 144.00
Weighted-Average Exercise Price Per Share, Non-vested options outstanding at end of period (in usd per share) $ 0.00 $ 23.47 $ 22.42