Equity Based Compensation - Summary of Option Activity for Stock Options (Detail) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted Average Exercise Price, Outstanding, Beginning Balance	$ 8.65
Weighted Average Exercise Price, Granted	0.00
Weighted Average Exercise Price, Exercised	8.38
Weighted Average Exercise Price, Expired	0.00
Weighted Average Exercise Price, Forfeited	0.00
Weighted Average Exercise Price, Outstanding, Ending Balance	8.67		$ 8.65
Weighted Average Exercise Price, Exercisable	8.67
Weighted Average Exercise Price, Expected to vest	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted Average Remaining Contractual Life (Yrs.), Outstanding	4 years 4 months 18 days		5 years 29 days
Weighted Average Remaining Contractual Life (Yrs.), Exercisable	4 years 4 months 18 days
Aggregate Intrinsic Value, Outstanding	$ 6,281
Aggregate Intrinsic Value, Exercisable	6,281
Aggregate Intrinsic Value, Expected to vest	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares, Outstanding, Beginning Balance	600,000
Shares, Granted	0	0
Shares, Exercised	(50,000,000)
Shares, Expired	0
Shares, Forfeited	0
Shares, Outstanding, Ending Balance	550,000		600,000
Shares, Exercisable	550,000
Shares, Expected to vest	0