Deconsolidation of real estate properties carrying value.

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Amount before allowance of commercial loans issued to businesses to acquire, develop, construct, improve, or refinance land or building. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans covered under loss sharing agreements. The commercial mortgages for these properties is held by a consolidated securitization and not held by a third party lender.

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Amount before allowance of commercial loans issued to businesses to acquire, develop, construct, improve, or refinance land or building. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans covered under loss sharing agreements. The commercial mortgages for these properties is held by a third party lender and not held by a consolidated securitization.

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Number of industrial real estate properties deconsolidated.

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Number of mortgage liens properties.

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Number of real estate properties disposed.

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Number of retail property disposed.

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Remaining number of industrial real estate properties.

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Amount of gain (loss) from deconsolidation of subsidiary and derecognition of group of assets constituting transfer of business or nonprofit activity, excluding conveyance of oil and gas mineral rights and transfer of good or service in contract with customer.

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Gross amount of debt extinguished.

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No definition available.

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Amount of gain (loss) on sale or disposal of property, plant and equipment assets, including oil and gas property and timber property.

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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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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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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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Amount of debt for which creditor does not have general recourse to the debtor but rather has recourse only to the property used for collateral in the transaction or other specific property.

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No definition available.

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- Definition

Amount of real estate investments sold for entities with a substantial portion of business acquiring and holding investment real estate.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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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 investment property 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; and (7) other real estate investments.

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Amount of real estate investment property, 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; and (7) other real estate investments.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Investments in Real Estate - Additional Information (Detail)	1 Months Ended	3 Months Ended	6 Months Ended
	Aug. 31, 2018 USD ($) Property	Jun. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($) Property	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Real Estate Properties [Line Items]
Investments in real estate, net, Book Value		$ 177,178,000	$ 177,178,000		$ 245,904,000
Investments in real estate		190,849,000	190,849,000		274,672,000
Mortgages loans or other debt held by third parties		41,082,000	41,082,000		62,297,000
Mortgages loans held by consolidated securitizations		266,407,000	266,407,000		298,050,000
Impairment charges on real estate assets		21,625,000	30,816,000
Office
Real Estate Properties [Line Items]
Investments in real estate		77,056,000	77,056,000		130,125,000
Office and Retail
Real Estate Properties [Line Items]
Carrying value of asset held for sale		27,554,000	27,554,000
One Real Estate Properties
Real Estate Properties [Line Items]
Impairment charges on real estate assets		17,522,000
Two Other Retail Real Estate Properties
Real Estate Properties [Line Items]
Impairment charges on real estate assets		3,440,000
Another Asset
Real Estate Properties [Line Items]
Impairment charges on real estate assets		662,000
Two Real Estate Assets
Real Estate Properties [Line Items]
Impairment charges on real estate assets			9,191,000
Assets Real Estate Properties
Real Estate Properties [Line Items]
Impairment charges on real estate assets			5,593,000
Other Asset
Real Estate Properties [Line Items]
Impairment charges on real estate assets			3,598,000
Industrial real estate properties
Real Estate Properties [Line Items]
Gains (losses) on deconsolidation				$ (15,947,000)
Industrial real estate properties \| Non Recourse Indebtedness \| Loan Payable On Real Estate
Real Estate Properties [Line Items]
Gains (losses) on deconsolidation				$ (15,947,000)
Number of industrial real estate properties deconsolidated \| Property				10
Deconsolidation of properties, carrying value				$ 38,516,000		$ 82,501,000
Cross-collateralized non-recourse debt related to deconsolidation of property				$ 54,475,000		$ 81,941,000
Number of mortgage liens properties \| Property				5
Carrying value of asset held for sale				$ 43,414,000
Extinguishment of debt				$ 27,467,000
Remaining Number Of Industrial Real Estate Properties \| Property				5
Scenario, Forecast
Real Estate Properties [Line Items]
Number of retail properties disposed \| Property	1
Scenario, Forecast \| Office
Real Estate Properties [Line Items]
Number of real estate properties disposed \| Property	1
Scenario, Forecast \| Office and Retail
Real Estate Properties [Line Items]
Gain or loss on the sale of asset	$ 0
Cost of sale	$ 30,000,000
Prior Year Disposal Group Held For Sale Or Disposed Of By Sale Not Discontinued Operations
Real Estate Properties [Line Items]
Gain (loss) on sale			(6,000)
Land
Real Estate Properties [Line Items]
Investments in real estate, net, Book Value		57,643,000	57,643,000		73,003,000
Building and Building Improvements
Real Estate Properties [Line Items]
Investments in real estate, net, Book Value		$ 133,206,000	$ 133,206,000		$ 201,669,000