Condensed Consolidated Statement of Equity (Unaudited) Statement - 9 months ended Sep. 30, 2017 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Cumulative Net Income Attributable to Common Stockholders	Cumulative Dividends
Beginning balance at Dec. 31, 2016	$ 1,653,414	$ 1,164	$ 2,917,914	$ (1,401)	$ 995,256	$ (2,259,519)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock	248,345	84	248,261
Common stock redemptions	(503)		(503)
Stock-based compensation	7,496	1	7,495
Net income	60,243				60,243
Reclassification of loss on forward starting interest rate swaps	127			127
Dividends to common stockholders ($0.90 per share)	(104,860)					(104,860)
Ending balance at Sep. 30, 2017	$ 1,864,262	$ 1,249	$ 3,173,167	$ (1,274)	$ 1,055,499	$ (2,364,379)