Equity-Based Compensation - Activity with Respect to SARs (Detail) - SARs - $ / 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	Sep. 30, 2015	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)	504,656	479,656	479,656	542,085	542,085	548,482	479,656	548,482	548,482
Number of Shares, Granted (in shares)		25,000				1,500
Number of Shares, Exercised (in shares)	(16,062)			(10,587)		(7,897)
Number of Shares, Activity for the three months ended of period (in shares)			0		0
Number of Shares, Forfeited (in shares)	(5,937)			(1,407)
Number of Shares, Issued and unvested as of end of period (in shares)	482,657	504,656	479,656	530,091	542,085	542,085	482,657	530,091	479,656
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Weighted Average Base Price [Roll Forward]
Weighted Average Base Price, Outstanding as of beginning of period (in dollars per share)	$ 10.56	$ 10.64	$ 10.64	$ 10.64	$ 10.64	$ 10.62	$ 10.64	$ 10.62	$ 10.62
Weighted Average Base Price, Granted (in dollars per share)		9.04				16.69
Weighted Average Base Price, Exercised (in dollars per share)	8.14			8.86		10.61
Weighted Average Base Price, Activity for the three months ended of period (in dollars per share)			0.00		0.00
Weighted Average Base Price, Forfeited (in dollars per share)	12.15			9.25
Weighted Average Base Price, Outstanding as of end of period (in dollars per share)	10.62	10.56	10.64	10.68	10.64	10.64	10.62	10.68	10.64
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, Outstanding as of beginning of period (in dollars per share)	5.75	5.80	5.80	5.80	5.80	5.79	5.80	5.79	5.79
Weighted Average Fair Value, Granted (in dollars per share)		4.80				8.99
Weighted Average Fair Value, Exercised (in dollars per share)	4.66			4.98		5.72
Weighted Average 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)	6.63			4.90
Weighted Average Fair Value, Outstanding as of end of period (in dollars per share)	$ 5.78	$ 5.75	$ 5.80	$ 5.82	$ 5.80	$ 5.80	$ 5.78	$ 5.82	$ 5.80
Number of shares issued (in shares)	3,213	0	0	2,405	0	1,869	3,213	4,274
First anniversary of grant date
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock awards vesting period							4 years
Vesting percentage							25.00%
Vested ratably each month over the subsequent 36 months
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock awards vesting period							36 months
Vesting percentage							75.00%