Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

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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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Fair value of all derivative assets designated as fair value hedging instruments.

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The difference between the carrying value and the sale price of real estate or properties that were intended to be sold or held for capital appreciation or rental income. This element refers to the gain (loss) included in earnings and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

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Fair value of all derivative assets designated as hedges of net investment in foreign operations.

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Financial Instruments and Fair Value Measurements - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Gain on disposition of properties		$ 33,000	$ 2,014,000	$ 33,000
Impairment charges	$ 1,400,000		1,400,000
Reclassification adjustment related to derivatives from AOCI to interest expense			3,400,000
Derivatives designated as fair value hedges	0		0		$ 0
Derivative designated to hedges of net investments in foreign operations	0		$ 0		0
Nonrecurring \| Disposal group, held-for-sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impairment charges				$ 0
Nonrecurring \| Disposal group, held-for-sale \| Fund IV \| 210 Bowery property
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Gain on disposition of properties					0
Impairment charges	1,400,000				$ 0
Nonrecurring \| Noncontrolling Interests \| Disposal group, held-for-sale \| Fund IV \| 210 Bowery property
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impairment charges	$ 1,100,000