Income Per Common Share - Summary of Diluted Income Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Net income attributable to common stockholders - basic and diluted	$ 11,549	$ 9,481	$ 27,355	$ 17,230
Weighted average number of common shares outstanding	31,323,600	31,237,275	31,294,596	31,318,682
Dilutive effect of outstanding common stock awards after application of the Treasury Stock Method	54,190	51,334	57,395	24,548
Diluted shares outstanding	31,377,790	31,288,609	31,351,991	31,343,230
Basic income per share attributable to common stockholders	$ 0.37	$ 0.30	$ 0.87	$ 0.55
Diluted income per share attributable to common stockholders	$ 0.37	$ 0.30	$ 0.87	$ 0.55