Earnings Per Common Share - Reconciliation of Weighted-Average Common Shares Outstanding Used in Calculation of Basic EPS to Diluted EPS (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Numerator:
Net income (loss)	$ 5,003	$ 727	$ 2,266	$ 2,038	$ 630	$ 1,967	$ (10,342)	$ (398)	$ 10,034	$ (8,143)	$ (395)
Less: Net income allocated to participating securities									(286)	0	0
Numerator for basic and diluted earnings (loss) available to common stockholders									$ 9,748	$ (8,143)	$ (395)
Denominator:
Weighted-average basic common shares outstanding (in shares)	47,660	39,125	31,278	31,257	24,419	22,255	22,231	22,228	37,380	22,788	22,228
Weighted-average diluted common shares outstanding (in shares)	47,660	39,125	31,278	31,257	24,586	22,436	22,231	22,228	37,380	22,788	22,228
Earnings (loss) per common share, basic (in usd per share)	$ 0.10	$ 0.02	$ 0.07	$ 0.06	$ 0.03	$ 0.09	$ (0.47)	$ (0.02)	$ 0.26	$ (0.36)	$ (0.02)
Earnings (loss) per common share, diluted (in usd per share)	$ 0.10	$ 0.02	$ 0.07	$ 0.06	$ 0.03	$ 0.09	$ (0.47)	$ (0.02)	$ 0.26	$ (0.36)	$ (0.02)