SCHEDULE III-Consolidated Real Estate and Accumulated Depreciation Rollforward (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Real estate assets
Balance, beginning of period		$ 2,301,006	$ 2,246,028	$ 2,136,824
Property acquisitions		270,602	0	0
Improvements		44,755	59,199	119,719
Cost of Real Estate Sold		0	0	(7,396)
Other	[1]	(2,225)	(4,221)	(3,119)
Balance, end of period		2,614,138	2,301,006	2,246,028
Accumulated depreciation
Balance, beginning of period		469,460	411,166	361,424
Additions-depreciation		70,196	62,515	54,534
Cost of Real Estate Sold		0	0	(2,334)
Other	[1]	(2,225)	(4,221)	(2,458)
Balance, end of period		$ 537,431	$ 469,460	$ 411,166

[1] Other deductions for the years ended December 31, 2017, 2016 and 2015 represent the write-off of fully depreciated assets.