Stock-Based Compensation - Weighted Average Grant Date of SARs Granted and Total Intrinsic Value of SARs Exercised (Detail) - Stock Appreciation Rights (SARs) [Member] - 2011 Equity Incentive 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	217	246	318
Weighted average grant-date fair value per SAR	$ 8.17	$ 7.20	$ 6.08
Intrinsic value of SARs exercised	$ 5,957	$ 391	$ 488
Fair value of vested	$ 1,302	$ 1,553	$ 1,298