Equity-Based Compensation - Activity with Respect to SARs (Detail) - SARs - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of Shares, Issued and unvested, beginning of period	548,482	1,232,808	4,338,250
Number of Shares, Granted	1,500	500	2,500
Number of Shares, Exercised	(68,638)	(679,606)	(3,045,700)
Number of Shares, Forfeited	(1,688)	(5,220)	(62,242)
Number of Shares, Issued and unvested, end of period	479,656	548,482	1,232,808
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Weighted Average Base Price [Roll Forward]
Weighted Average Base Price, Beginning of period (in dollars per share)	$ 10.62	$ 8.86	$ 7.80
Weighted Average Base Price, Granted (in dollars per share)	16.69	17.31	16.19
Weighted Average Base Price, Exercised (in dollars per share)	10.67	7.35	14.42
Weighted Average Base Price, Forfeited (in dollars per share)	9.35	10.14	10.25
Weighted Average Base Price, End of period (in dollars per share)	10.64	10.62	8.86
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted Average Fair Value, Beginning of period (in dollars per share)	5.79	4.99	4.56
Weighted Average Fair Value, Granted (in dollars per share)	8.99	9.48	9.83
Weighted Average Fair Value, Exercised (in dollars per share)	5.79	3.60	8.64
Weighted Average Fair Value, Forfeited (in dollars per share)	4.95	5.43	5.51
Weighted Average Fair Value, End of period (in dollars per share)	$ 5.80	$ 5.79	$ 4.99
Number of shares issued	11,261	253,853	992,390