For sales-type and direct financing leases, total contingent rentals received during the period.

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Gross amount of debt extinguished.

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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 carrying amount of the outstanding balance due under the mortgage loan.

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The number of real estate properties owned as of the balance sheet date.

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Cash inflow related to amounts received in advance from a potential buyer showing or confirming an intention to complete an acquisition of land, buildings, other structures, or any item classified as real estate.

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Amount of cash inflow for the sale of long-lived, physical assets used to produce goods and services and not intended for resale, classified as other.

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Carrying amount of income producing properties held for rental.

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The number of properties sold during the period.

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Property Dispositions (Narratives) (Details) $ in Thousands			1 Months Ended			3 Months Ended				9 Months Ended		12 Months Ended
Property Dispositions (Narratives) (Details) $ in Thousands	Feb. 29, 2016 USD ($)	Dec. 18, 2015 USD ($)	Jul. 31, 2016 USD ($)	Apr. 30, 2016 USD ($)	Jul. 31, 2015 USD ($)	Sep. 30, 2016 USD ($) property	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) property	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) property	Sep. 30, 2015 USD ($) property	Dec. 31, 2015 USD ($) property
Discontinued Operation Additional Disclosures
Gain on sale of real estate, net of tax						$ 49,126			$ 1,779	$ 68,070	$ 2,980
Carrying value of property						5,221,986		$ 5,309,925		5,221,986		$ 5,309,925
Allocation of goodwill to the cost basis of properties sold or classified as held-for-sale										33,981
Impairment charges						14,441			19,438	49,870	22,711
Additional lease term		15 years
Rental payment received		$ 25,000
Lease termination fee	$ 22,200
Lease termination income							$ 32,200					15,000
Defeased mortgage												36,500
Loss on extinguishment of debt, net of tax												$ 5,300
Deposit for real estate to be purchased								$ 12,700
Owned Real Estate
Discontinued Operation Additional Disclosures
Gain on sale of real estate, net of tax						$ 49,126			1,779	68,070	2,980
Allocation of goodwill to the cost basis of properties sold or classified as held-for-sale										$ 33,981
Number of real estate properties \| property						910				910
Impairment charges						$ 14,441			19,438	$ 49,870	22,711
Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations
Discontinued Operation Additional Disclosures
Number of real estate properties \| property						14				14
Disposal Group, Including Discontinued Operation, Impairment of Real Estate						$ 5,524			$ 1,389	$ 40,952	$ 4,071
Discontinued Operations, Disposed of by Sale
Discontinued Operation Additional Disclosures
Properties sold \| property						3				10	11
Proceeds from the sale of properties					$ 1,400	$ 192,000				$ 392,600	$ 28,800
Gain on sale of real estate, net of tax			$ 11,600	$ 16,400	$ 600	$ 37,400				39,900	2,400
Carrying value of property			13,700	39,800
Carrying value of mortgage loan			$ 27,000	$ 60,900
Discontinued Operations, Disposed of by Sale \| Owned Real Estate
Discontinued Operation Additional Disclosures
Allocation of goodwill to the cost basis of properties sold or classified as held-for-sale										32,900	$ 1,100
Discontinued Operations, Disposed of by Sale \| Noncontrolling interest
Discontinued Operation Additional Disclosures
Gain on sale of real estate, net of tax										$ 900
Disposal Group, Held-for-sale, Not Discontinued Operations
Discontinued Operation Additional Disclosures
Number of real estate properties \| property						16				16
Discontinued Operations, Held-for-sale
Discontinued Operation Additional Disclosures
Proceeds from the sale of properties							44,400
Gain on sale of real estate, net of tax							$ (10,700)
Number of real estate properties \| property								2				2