Summary of Significant Accounting Policies - Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Numerator:
Net income	$ 17,916	$ 38,455
Income from consolidated joint venture attributable to noncontrolling interest	(1,599)	(2,439)
Preferred stock dividends	(3,207)	(3,207)
Distributions paid on unvested restricted stock compensation	(61)	(59)
Undistributed income allocated to unvested restricted stock compensation	(9)	(117)
Numerator for basic and diluted income attributable to common stockholders	$ 13,040	$ 32,633
Denominator:
Weighted average basic and diluted common shares outstanding (in shares)	227,219	224,282
Basic and diluted income attributable to common stockholders per common share (in dollars per share)	$ 0.06	$ 0.15