Investments in Joint Ventures (Narrative) (Details)	3 Months Ended
Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)
Schedule of Equity Method Investments [Line Items]
Number of joint ventures accounted for under equity method investments	2
Maximum guaranteed amount of loans utilized for construction and development activities for joint ventures	$ 0
Maximum Investments by Formed Unconsolidated Joint Venture	450,000,000
Fees earned for property and asset management, construction, development, and other services to joint ventures	$ 1,500,000	$ 1,400,000
Maximum [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment ownership percentage	31.30%
Minimum [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment ownership percentage	20.00%

Revenue earned by providing property management, construction, development, and other services to joint ventures.

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- Definition

Maximum investment by formed unconsolidated joint venture including leverage of approximately 70% of the estimated value of the underlying real estate

+ References

No definition available.

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- Definition

Number of joint ventures accounted for under equity method investments.

+ References

No definition available.

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

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- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=115931803&loc=d3e12069-110248

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- Definition

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.

+ References

No definition available.

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