Earnings per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share [Abstract]
Net Income (Loss) Attributable to Parent	$ 27,253	$ 23,689
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	28,331	23,894
Numerator:
Preferred Stock Dividends, Income Statement Impact	6,279	6,279
Less: Dividends paid on unvested restricted shares	(312)	(328)
Net income attributable to common shareholders excluding amounts attributable to unvested restricted shares	$ 20,662	$ 17,082
Denominator:
Weighted-average number of common shares - basic (in shares)	172,796,998	174,193,671
Unvested restricted shares (in shares)	59,232	75,144
Weighted-average number of common shares - diluted (in shares)	172,856,230	174,268,815
Net income per share attributable to common shareholders - basic (in dollars per share)	$ 0.12	$ 0.10
Net income per share attributable to common shareholders - diluted (in dollars per share)	$ 0.12	$ 0.10