Equity-Based Compensation - Share Activity with Respect to Restricted Stock (Detail) - Restricted Stock - $ / shares	3 Months Ended				6 Months Ended	12 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2016	Dec. 31, 2015
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 as of beginning of period	2,668,975	3,480,828	3,508,624	3,755,275	3,480,828	3,755,275
Number of Shares, Granted	112,397	434,283	140,416	441,256
Number of Shares, Vested	(81,391)	(657,317)	(63,017)	(644,247)
Number of Shares, Forfeited	(7,500)	(588,819)		(43,660)
Number of Shares, Issued and unvested as of end of period	2,692,481	2,668,975	3,586,023	3,508,624	2,692,481	3,480,828
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted Average Grant Date Fair Value, Issued and unvested as of beginning of period (in dollars per share)	$ 15.93	$ 16.51	$ 15.75	$ 15.94	$ 16.51	$ 15.94
Weighted Average Grant Date Fair Value, Granted (in dollars per share)	9.33	8.44	13.17	16.21
Weighted Average Grant Date Fair Value, Vested (in dollars per share)	13.33	18.75	10.80	19.70
Weighted Average Grant Date Fair Value, Forfeited (in dollars per share)	8.44	10.69		17.85
Weighted Average Grant Date Fair Value, Issued and unvested as of end of period (in dollars per share)	$ 15.73	$ 15.93	$ 15.74	$ 15.75	$ 15.73	$ 16.51