Related Party Transactions - Schedule of fees charged to unconsolidated joint ventures (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Management fees
Related Party Transaction [Line Items]
Revenues	$ 10,180	$ 10,542
Unconsolidated Joint Ventures and Third Party Managed Properties
Related Party Transaction [Line Items]
Revenues	7,977	8,283
Unconsolidated Joint Ventures and Third Party Managed Properties \| Management fees
Related Party Transaction [Line Items]
Revenues	4,481	4,679
Unconsolidated Joint Ventures and Third Party Managed Properties \| Development and leasing fees
Related Party Transaction [Line Items]
Revenues	$ 3,496	$ 3,604

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130543-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130539-203045

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130545-203045

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration