SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION - Reconciliation of Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance at beginning of year	$ 287,066	$ 298,703	$ 256,015
Depreciation related to real estate	73,268	49,269	49,775
Property dispositions	(20,472)	(27,829)	(7,087)
Deconsolidation of previously consolidated investments	0	(33,077)	0
Balance at end of year	$ 339,862	$ 287,066	$ 298,703