Real Estate Investments and Related Intangibles - Property Dispositions and Real Estate Assets Held for Sale Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) property	Dec. 31, 2017 USD ($) property	Dec. 31, 2016 USD ($) property
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds after debt assumptions and closing costs	$ 502,289	$ 445,525	$ 1,000,700
Gain on disposition of real estate and real estate assets held for sale, net	94,331	61,536	45,524
Proceeds from disposition of discontinued operations	$ 122,915	$ 0	0
Goodwill allocated to dispositions and held for sale assets			$ 73,200
Number of properties classified held for sale | property	5	30
Carrying value of properties classified as held for sale	$ 2,600
Consolidated Property Dispositions, 2018 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties disposed | property	149
Number of properties secured by each non-recourse loan | property	1
Aggregate proceeds	$ 526,400
Company's share of proceeds	504,300
Proceeds after debt assumptions and closing costs	496,700
Gain on disposition of real estate and real estate assets held for sale, net	$ 96,200
Red Lobster [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties disposed | property	34	31	70
Number of real estate properties disposed in non monetary exchange | property		15
Unconsolidated Property Dispositions, 2018 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Company's share of proceeds	$ 17,100
Number of disposed properties owned by unconsolidated joint ventures | property	1
Proceeds from disposition of discontinued operations	$ 34,100
Proceeds from after debt repayments and closing costs	5,600
Debt repayments	20,400
Net gain (loss) on sale of properties	700
Consolidated Property Dispositions, 2017 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties disposed | property		137
Number of consolidated joint venture disposed of | property		1
Number of properties secured by each non-recourse loan | property		6
Aggregate proceeds		$ 594,900
Company's share of proceeds		574,400
Proceeds after debt assumptions and closing costs		445,500
Gain on disposition of real estate and real estate assets held for sale, net		$ 64,700
Number of real estate properties disposed in non monetary exchange | property		15
Debt assumed		$ 66,000
Consolidated Property Disposition, 2016 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties disposed | property			301
Aggregate proceeds			$ 1,082,800
Company's share of proceeds			1,041,300
Proceeds after debt assumptions and closing costs			958,400
Gain on disposition of real estate and real estate assets held for sale, net			45,700
Debt assumed			55,000
Goodwill allocated to dispositions and held for sale assets			67,800
Unconsolidated Property Dispositions, 2016 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Company's share of proceeds			$ 102,100
Number of disposed properties owned by unconsolidated joint ventures | property			1
Proceeds from disposition of discontinued operations			$ 113,500
Proceeds from after debt repayments and closing costs			42,300
Debt repayments			57,000
Net gain (loss) on sale of properties			10,200
Property Disposition, 2018 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) related to held for sale	$ (1,900)
Property Dispositions, 2017 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) related to held for sale		(3,100)
Property Dispositions 2016 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill allocated to dispositions and held for sale assets			3,200
Gain (loss) related to held for sale			$ (5,100)
Foreign Tax Authority [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Tax provision for the gain on sale of property		$ 1,700