Employee Benefit Plans - Status of Restricted Stock Awarded under Restricted Stock Plan (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Non vested balance at beginning of period (in shares)	128,500	278,900	569,296
Granted (in shares)	0	13,585	58,669
Forfeited (in shares)	0	(30,800)	(206,282)
Vested (in shares)	(128,500)	(133,185)	(142,783)
Non vested balance at end of period (in shares)	0	128,500	278,900
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Non vested balance at beginning of period (in dollars per share)	$ 5.85	$ 6.28	$ 5.26
Granted (in dollars per share)	0.00	17.02	4.42
Forfeited (in dollars per share)	0.00	6.27	4.59
Vested (in dollars per share)	5.85	7.80	3.87
Non vested balance at end of period (in dollars per share)	$ 0.00	$ 5.85	$ 6.28
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Non vested balance at beginning of period (in shares)	437,946	413,288	371,502
Granted (in shares)	100,892	89,702	247,463
Forfeited (in shares)	(11,352)	(54,506)	(135,104)
Vested (in shares)	0	(10,538)	(70,573)
Non vested balance at end of period (in shares)	527,486	437,946	413,288
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Non vested balance at beginning of period (in dollars per share)	$ 7.09	$ 5.09	$ 4.34
Granted (in dollars per share)	23.15	16.63	5.83
Forfeited (in dollars per share)	11.55	6.15	4.60
Vested (in dollars per share)	0.00	14.88	3.22
Non vested balance at end of period (in dollars per share)	$ 10.17	$ 7.09	$ 5.09