Summary of Significant Accounting Policies - Investments in Unconsolidated Entities (Details) - Equity Method Investments - USD ($)	3 Months Ended	6 Months Ended
Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Equity method investment	$ 63,100,000		$ 63,100,000		$ 67,600,000
RB Development Holding Company, LLC (1) (RBDHC)
Schedule of Equity Method Investments [Line Items]
Ownership Interest	0.00%		0.00%		63.00%
Income (loss) from investments	$ 0	$ (27,000)	$ 107,000	$ 8,000
Equity method investment	$ 0		$ 0		$ 1,927,000
RB Multifamily Investors LLC
Schedule of Equity Method Investments [Line Items]
Ownership Interest	0.00%		0.00%		70.00%
Income (loss) from investments	$ 1,000	1,680,000	$ 2,262,000	2,827,000
Equity method investment	$ 0		$ 0		$ 56,891,000
Morrocroft Neighborhood Stabilization Fund II, LP
Schedule of Equity Method Investments [Line Items]
Ownership Interest	11.00%		11.00%		13.00%
Income (loss) from investments	$ 234,000	0	$ 591,000	9,000
Equity method investment	$ 10,579,000		$ 10,579,000		$ 8,753,000
Evergreens JV Holdings, LLC
Schedule of Equity Method Investments [Line Items]
Ownership Interest	85.00%		85.00%		0.00%
Income (loss) from investments	$ 10,000	0	$ 10,000	0
Equity method investment	$ 3,700,000		$ 3,700,000		$ 0
Bent Tree JV Holdings, LLC
Schedule of Equity Method Investments [Line Items]
Ownership Interest	78.00%		78.00%		0.00%
Income (loss) from investments	$ 100,000	0	$ 100,000	0
Equity method investment	$ 9,780,000		$ 9,780,000		$ 0
Summerchase LR Partners LLC
Schedule of Equity Method Investments [Line Items]
Ownership Interest	80.00%		80.00%		0.00%
Income (loss) from investments	$ 10,000	0	$ 10,000	0
Equity method investment	$ 4,360,000		$ 4,360,000		$ 0
Lake Mary Realty Partners, LLC
Schedule of Equity Method Investments [Line Items]
Ownership Interest	80.00%		80.00%		0.00%
Income (loss) from investments	$ 20,000	0	$ 20,000	0
Equity method investment	$ 10,350,000		$ 10,350,000		$ 0
The Preserve at Port Royal Venture, LLC
Schedule of Equity Method Investments [Line Items]
Ownership Interest	77.00%		77.00%		0.00%
Income (loss) from investments	$ 100,000	0	$ 100,000	0
Equity method investment	$ 11,910,000		$ 11,910,000		$ 0
WR Savannah Holdings, LLC
Schedule of Equity Method Investments [Line Items]
Ownership Interest	90.00%		90.00%		0.00%
Income (loss) from investments	$ 60,000	$ 0	$ 60,000	0
Equity method investment	$ 12,340,000		$ 12,340,000		$ 0
RB Distressed Investors LLC
Schedule of Equity Method Investments [Line Items]
Ownership Interest	9.00%		9.00%		0.00%
Income (loss) from investments	$ 0		$ 0	$ 0
Equity method investment	$ 36,000		$ 36,000		$ 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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+ 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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