Equity-Based Compensation - Non-Management Director Equity-Based Compensation (Detail) - Non-Management Directory Equity Based Compensation Plan - Deferred Stock Units - $ / shares	3 Months Ended						9 Months Ended	12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 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 (in shares)	45,000	90,000	90,000	90,000	0	22,500	90,000	22,500
Number of Shares, Vested (in shares)	(5,625)	(30,000)				(22,500)
Number of Shares, Granted (in shares)					90,000
Number of Shares, Activity for the three months ended of period (in shares)			0	0
Number of Shares, Forfeited (in shares)		(15,000)
Number of Shares, Issued and unvested as of end of period (in shares)	39,375	45,000	90,000	90,000	90,000	0	39,375	90,000
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)	$ 13.17	$ 13.17	$ 13.17	$ 13.17	$ 0.00	$ 17.63	$ 13.17	$ 17.63
Weighted Average Grant Date Fair Value, Vested (in dollars per share)	13.17	13.17				17.63
Weighted Average Grant Date Fair Value, Granted (in dollars per share)					13.17
Weighted Average Grant Date Fair Value, Activity for the three months ended of period (in dollars per share)			0.00	0.00
Weighted Average Grant Date Fair Value, Forfeited (in dollars per share)		13.17
Weighted Average Grant Date Fair Value, Issued and unvested as of end of period (in dollars per share)	$ 13.17	$ 13.17	$ 13.17	$ 13.17	$ 13.17	$ 0.00	$ 13.17	$ 13.17