Income Taxes (Tax Treatment of Distributions and Consolidated Benefit for Income Taxes) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Tax treatment of distributions:
Ordinary income (in dollars per share)	$ 2.68216	$ 3.02368	$ 2.61271
Qualified ordinary income (in dollars per share)	0.05794	0.01632	0.10474
Long-term capital gain (in dollars per share)	0.11613	0.00000	0.16224
Unrecaptured Section 1250 gain (in dollars per share)	0.10877	0.00000	0.08531
Distribution reported for 1099-DIV purposes (in dollars per share)	$ 2.96500	$ 3.04000	$ 2.96500
REIT distribution requirement (as a percent)	90.00%	90.00%	90.00%
Provision (benefit) for income taxes
Current - Federal	$ (2,991)	$ 138	$ 878
Current - State	1,241	1,453	0
Deferred - Federal	(19,539)	(25,962)	(3,338)
Deferred - State	(3,634)	(3,054)	(1,772)
Current - Foreign	1,067	953	327
Deferred - Foreign	(7,487)	(12,812)	(4,827)
Income tax benefit	$ (31,343)	$ (39,284)	$ (8,732)