Real Estate Investments - Property Dispositions and Held for Sale Assets Narrative (Details)		9 Months Ended
	Jun. 27, 2017 property	Sep. 30, 2017 USD ($) property	Sep. 30, 2016 USD ($) property
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties disposed | property		6
Number of properties secured by each non-recourse loan | property	4	6
Proceeds after debt assumptions and closing costs		$ 366,237,000	$ 615,246,000
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		$ 1,700,000
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		112
Aggregate proceeds		$ 507,500,000
Company's share of proceeds		491,000,000
Proceeds after debt assumptions and closing costs		366,200,000
Debt assumed		66,000,000
Gain related to sale		$ 54,900,000
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		24	47
Number of real estate properties disposed in non monetary exchange | property		15
Consolidated Property Dispositions, 2016 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties disposed | property			223
Aggregate proceeds			$ 672,500,000
Company's share of proceeds			646,400,000
Proceeds after debt assumptions and closing costs			573,000,000
Debt assumed			55,000,000
Gain related to sale			50,700,000
Goodwill included in sale			28,800,000
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			$ 102,100,000
Number of disposed properties owned by unconsolidated joint ventures | property			1
Net proceeds			$ 113,500,000
Proceeds from after debt repayments and closing costs			42,300,000
Debt repayments			57,000,000
Gain related to sale of unconsolidated entities			10,200,000
Property Dispositions, 2017 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties classified held for sale | property		2
Net loss on sale of properties		$ 500,000
Goodwill allocated to dispositions and held for sale assets		$ 0
Property Dispositions, 2016 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net loss on sale of properties			5,000,000
Goodwill allocated to dispositions and held for sale assets			$ 22,700,000