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		6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Numerator:
Net income	$ 7,631	$ 2,266	$ 13,133	$ 4,304	$ 10,034
Less: Net income allocated to participating securities	(69)	(81)	(147)	(117)
Numerator for basic and diluted earnings available to common stockholders	$ 7,562	$ 2,185	$ 12,986	$ 4,187
Denominator:
Weighted-average basic common shares outstanding (in shares)	57,478	31,278	52,789	31,268
Weighted-average diluted common shares outstanding (in shares)	57,478	31,278	52,789	31,268
Earnings (loss) per common share, basic (in usd per share)	$ 0.13	$ 0.07	$ 0.25	$ 0.13
Earnings (loss) per common share, diluted (in usd per share)	$ 0.13	$ 0.07	$ 0.25	$ 0.13