Mortgage Loans Payable and Unsecured Credit Facility (Effect of Derivative Financial Instruments on Consolidated Statements of Operations and Consolidated Statements of Equity) (Details) - USD ($)	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Designation/Cash Flow [Member] \| Interest Rate Swap [Member]
Derivative Instruments Gain Loss [Line Items]
(Loss) gain recognized in other comprehensive (loss) income (effective portion)	$ (552,000)	$ (2,883,000)	$ (18,141,000)	$ (15,837,000)
Continuing Operations [Member]
Derivative Instruments Gain Loss [Line Items]
Gain (loss) recognized in other comprehensive (loss) income reclassified into earnings (effective portion)	$ (2,032,000)	$ 216,000	$ (4,019,000)	$ 1,300,000

Amount before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=121641772&loc=d3e637-108580

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121558989&loc=d3e80720-113993

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121641772&loc=SL7669646-108580

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