Equity Based Compensation - Summary of Option Activity for Stock Options With Market Condition Vesting (Detail) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, Outstanding, Beginning Balance	600,000
Shares, Exercised	(50,000)
Shares, Outstanding, Ending Balance	550,000	600,000
Shares, Exercisable	550,000
Shares, Expected to vest	0
Weighted Average Exercise Price, Outstanding, Beginning Balance	$ 8.65
Weighted Average Exercise Price, Exercised	8.38
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
Weighted Average Remaining Contractual Life (Yrs.), Outstanding	4 years 7 months 21 days	5 years 29 days
Weighted Average Remaining Contractual Life (Yrs.), Exercisable	4 years 7 months 21 days
Weighted Average Remaining Contractual Life (Yrs.), Expected to vest
Aggregate Intrinsic Value, Exercised	$ 1,026
Aggregate Intrinsic Value, Outstanding	9,828
Aggregate Intrinsic Value, Exercisable	9,828
Aggregate Intrinsic Value, Expected to vest	$ 0
Market Based Vesting Conditions [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, Outstanding, Beginning Balance	100,000
Shares, Exercised	(26,666)
Shares, Outstanding, Ending Balance	73,334	100,000
Shares, Exercisable	40,000
Shares, Expected to vest	0
Weighted Average Exercise Price, Outstanding, Beginning Balance	$ 25.95
Weighted Average Exercise Price, Exercised	25.95
Weighted Average Exercise Price, Outstanding, Ending Balance	25.95	$ 25.95
Weighted Average Exercise Price, Exercisable	25.95
Weighted Average Exercise Price, Expected to vest	$ 0
Weighted Average Remaining Contractual Life (Yrs.), Outstanding	1 year 9 months 15 days	2 years 3 months 11 days
Weighted Average Remaining Contractual Life (Yrs.), Exercisable	1 year 9 months 15 days
Weighted Average Remaining Contractual Life (Yrs.), Expected to vest
Aggregate Intrinsic Value, Exercised	$ 76
Aggregate Intrinsic Value, Outstanding	43
Aggregate Intrinsic Value, Exercisable	24
Aggregate Intrinsic Value, Expected to vest	$ 0