Reportable Segments (Reconciliation to Consolidated) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Net income (loss)	$ (10,183)	$ 98,942
Depreciation and amortization	33,998	37,609
Acquisition related expenses	0	60
Asset management and acquisition fees	8,859	9,366
General and administrative expenses	2,902	3,146
(Gain) loss on derivatives	(351)	12
Gain on sale of real estate investments	(19)	(85,188)	$ (364,300)
Foreign currency (gains) losses	1,220	(6,619)
Interest expense	14,999	14,684
Other (income) expenses	(263)	(102)
(Benefit) provision for income taxes	(317)	(848)
Total property revenues in excess of expenses	50,845	71,062
Segment Reconciling Items
Segment Reporting Information [Line Items]
Net income (loss)	(10,183)	98,942
Depreciation and amortization	33,998	37,609
Acquisition related expenses	0	60
Asset management and acquisition fees	8,859	9,366
General and administrative expenses	2,902	3,146
(Gain) loss on derivatives	(351)	12
Gain on sale of real estate investments	(19)	(85,188)
Foreign currency (gains) losses	1,220	(6,619)
Interest expense	14,999	14,684
Other (income) expenses	(263)	(102)
(Benefit) provision for income taxes	(317)	(848)
Total property revenues in excess of expenses	$ 50,845	$ 71,062