Investments - Summary of Owned Real Estate Activity (Footnote) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Real Estate [Line Items]
Revenue producing capitalized expenditures	$ 7,600
Capitalized maintenance expenditures	1,600
Impairments on owned real estate	40,164	$ 3,692
Allowance for credit losses on direct financing leases	304	$ 0
Operating lease held in use land and buildings, net	5,146,530
Intangible lease assets, net	381,398		$ 385,079
Real estate assets under direct financing leases, net	7,300		14,465
Real estate assets held for sale, net	3,126		1,144
Intangible lease liabilities, net	(124,097)		$ (127,335)
Net balance	5,414,257
Held-in-use
Real Estate [Line Items]
Gain on disposal of assets for properties	600
Held-for-sale
Real Estate [Line Items]
Gain on disposal of assets for properties	$ 100

Net Operating Lease Real Estate Held for Investment.

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The cash outflow for capital improvements non revenue producing.

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Payments for capital improvements revenue producing.

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Amount after amortization of leases acquired as part of a real property acquisition at below market lease rate with a finite life.

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Amount of expense (reversal of expense) for expected credit loss on net investment in direct financing lease.

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Amount of net investment in direct financing lease.

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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The net gain (loss) resulting from sales and other disposals of real estate owned for investment purposes.

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The charge against earnings in the period to reduce the carrying amount of real property to fair value.

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Carrying amount as of the balance sheet date of investments in land and buildings held for sale, excluding real estate considered to be inventory of the entity.

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Amount of real estate investments, net of accumulated depreciation, which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; (7) other real estate investments; (8) real estate joint ventures; and (9) unconsolidated real estate and other joint ventures not separately presented.

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