Summary of Significant Accounting Policies - Investments in Unconsolidated Entities (Details) - Equity Method Investments - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Carrying Amount	$ 65,800		$ 67,600
RB Development Holding Company, LLC
Schedule of Equity Method Investments [Line Items]
Ownership Interest	63.00%		63.00%
Carrying Amount	$ 2,034		$ 1,927
Income (Loss)	$ 107	$ 35
RB Multifamily Investors LLC
Schedule of Equity Method Investments [Line Items]
Ownership Interest	70.00%		70.00%
Carrying Amount	$ 54,814		$ 56,891
Income (Loss)	$ 1,756	1,147
Morrocroft Neighborhood Stabilization Fund II, LP
Schedule of Equity Method Investments [Line Items]
Ownership Interest	11.00%		13.00%
Carrying Amount	$ 8,950		$ 8,753
Income (Loss)	$ 357	$ 0

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=66022249&loc=d3e33749-111570

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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For each line item in the statement of financial position, the amounts of gains and losses from fair value changes included in earnings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14172-108612

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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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No definition available.

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