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		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Numerator:
Net income (loss)	$ 727	$ 1,967	$ 5,031	$ (8,773)	$ (8,143)
Less: Net income allocated to participating securities	(80)	0	(209)	0
Numerator for basic and diluted earnings (loss) available to common stockholders	$ 647	$ 1,967	$ 4,822	$ (8,773)
Denominator:
Weighted-average basic common shares outstanding (in usd per share)	39,125	22,255	33,916	22,238
Weighted-average diluted common shares outstanding (in usd per share)	39,125	22,436	33,916	22,238
Earnings (loss) per common share, basic	$ 0.02	$ 0.09	$ 0.14	$ (0.39)
Earnings (loss) per common share, diluted	$ 0.02	$ 0.09	$ 0.14	$ (0.39)