Earnings Per Share - Basic and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Numerator:
Net income attributable to Company	$ 14,336	$ 14,435	$ 33,517	$ 31,386
Less: Preferred stock dividends	(3,225)	(3,225)	(6,450)	(6,450)
NET INCOME ATTRIBUTABLE TO COMPANY'S COMMON STOCKHOLDERS	11,111	11,210	27,067	24,936
Net income attributable to Company's common stockholders- Diluted	$ 11,111	$ 11,210	$ 27,067	$ 24,936
Denominator:
Weighted average basic and diluted common shares outstanding (in shares)	111,863	109,489	111,792	109,445
EPS:
Basic Earnings per Common Share (in dollars per share)	$ 0.10	$ 0.10	$ 0.24	$ 0.23
Diluted Earnings per Common Share (in dollars per share)	$ 0.10	$ 0.10	$ 0.24	$ 0.23