Stockholders' Equity - Summary of Stock Appreciation Rights Activity (Detail) - Stock appreciation rights [Member] - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock appreciation rights, Granted	0	0	0
Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock appreciation rights, Outstanding at December 31, 2014	1,376,456
Number of stock appreciation rights, Exercised	(61,172)
Number of stock appreciation rights, Forfeited	(17,156)
Number of stock appreciation rights, Outstanding at December 31, 2015	1,298,128	1,376,456
Number of stock appreciation rights, Vested and exercisable at December 31, 2015	1,290,720
Weighted Average Exercise Price, Outstanding at December 31, 2014	$ 12.03
Weighted Average Exercise Price, Exercised	11.60
Weighted Average Exercise Price, Forfeited	11.60
Weighted Average Exercise Price, Outstanding at December 31, 2015	12.05	$ 12.03
Weighted Average Exercise Price, Vested and exercisable at December 31, 2015	$ 12.05
Weighted Average Remaining Contractual Term (in years), Outstanding at December 31, 2015	5 years 11 months 16 days
Weighted Average Remaining Contractual Term (in years), Vested and exercisable at December 31, 2015	5 years 11 months 16 days
Aggregate Intrinsic Value, Outstanding at December 31, 2015	$ 47.1
Aggregate Intrinsic Value, Vested and exercisable at December 31, 2015	$ 46.8