Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Numerator:
Net income	$ 19,855	$ 12,792	$ 25,576	$ 14,269
Less: Preferred stock dividends	(1,322)	0	(2,644)	0
Less: net income attributable to noncontrolling interest	(531)	(418)	(663)	(470)
Less: Net income attributable to participating securities	(156)	(75)	(247)	(153)
NET INCOME ATTRIBUTABLE TO COMMON STOCKHOLDERS	$ 17,846	$ 12,299	$ 22,022	$ 13,646
Denominator:
Weighted average shares of common stock outstanding - basic (in shares)	67,920,773	64,063,337	67,135,319	59,666,468
Effect of dilutive securities - performance units (in shares)	410,461	241,376	347,781	194,363
Weighted average shares of common stock outstanding - diluted (in shares)	68,331,234	64,304,713	67,483,100	59,860,831
Earnings per share — Basic
Net income attributable to common stockholders (in dollars per share)	$ 0.26	$ 0.19	$ 0.33	$ 0.23
Earnings per share — Diluted
Net income attributable to common stockholders (in dollars per share)	$ 0.26	$ 0.19	$ 0.33	$ 0.23