SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION - Reconciliation of Real Estate Properties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance at beginning of year	$ 3,382,000	$ 2,736,283	$ 2,208,595
Other improvements	55,763	152,129	162,760
Property acquisitions	179,292	761,400	418,396
Property dispositions or held for sale assets	(189,895)	(134,332)	(66,359)
Prior year purchase price allocation adjustments	0	(9,844)	0
Deconsolidation of previously consolidated investments	0	(123,636)	0
Consolidation of previously unconsolidated investments	39,322	0	12,891
Balance at end of year	$ 3,466,482	$ 3,382,000	$ 2,736,283