Stock-Based Compensation - Unrecognized Compensation Costs for Stock Options, Stock Awards and SARs (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation costs for stock options, stock awards and SARs	$ 2,163	$ 895
Stock Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation costs for stock options, stock awards and SARs	7,569	5,514
Stock Appreciation Rights (SARs) [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation costs for stock options, stock awards and SARs	$ 4,495	$ 1,859