Stock-Based Compensation - Summary of Weighted Average Grant-Date Fair Value of Common Stock Awarded and Cash Used to Settle Company's Obligation under Deferred Compensation (Detail) - Common Stock Awards [Member] - Deferred Compensation Plan [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Shares	8	10	13
Weighted average grant-date fair value	$ 25.06	$ 20.54	$ 16.76
Fair value of vested	$ 244	$ 212	$ 257
Cash used to settle the obligation	$ 65	$ 1,493	$ 1,014