Acquisition of Real Estate (Details Textual) $ in Thousands							1 Months Ended										12 Months Ended
	Dec. 12, 2016 USD ($)	Dec. 01, 2016 USD ($)	Nov. 10, 2016 USD ($)	Oct. 13, 2016 USD ($)	Jul. 14, 2016 USD ($)	Mar. 15, 2016 USD ($)	Dec. 20, 2016 USD ($)	Dec. 15, 2016 USD ($)	Oct. 31, 2016 USD ($)	May 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Nov. 30, 2015 USD ($)	Aug. 20, 2015 USD ($)	May 31, 2015 USD ($)	Mar. 26, 2015 USD ($)	Mar. 16, 2015 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Jan. 05, 2016 USD ($)	Dec. 14, 2015 USD ($)	Oct. 29, 2015 USD ($)	Aug. 19, 2015 USD ($)
Business Acquisition [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest						100.00%											10.00%
Business Acquisition Indirect Ownership, Amount												$ 2,900
Aggregate Property Level Revenues And Recent Acquisitions																	$ 46,900
Aggregate Property Level Net Income And Recent Acquisitions																	6,100
Noncash or Part Noncash Acquisition, Debt Assumed																	39,054	$ 32,942	$ 116,800
Equity Method Investment, Ownership Percentage			49.90%
Payments to Acquire Interest in Joint Venture			$ 4,200
Payments To Acquire Equity Method Investments																	26,864	65,093	10,135
Other Liabilities											$ 1,300						2,200	1,300
Depreciation																	23,600	12,400	8,400
Amortization of Intangible Assets																	$ 7,600	3,800	$ 4,500
Nivedan Apartments [Member]
Business Acquisition [Line Items]
Number of Real Estate Properties, Fee Simple				480
Payments to Acquire Interest in Joint Venture				$ 22,800
Business Acquisition, Percentage of Voting Interests Acquired				90.00%
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net				$ 68,250
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt				$ 48,400
The Brodie [Member]
Business Acquisition [Line Items]
Number of Real Estate Properties, Fee Simple			324
Payments to Acquire Interest in Joint Venture			$ 15,300
Business Acquisition, Percentage of Voting Interests Acquired			92.50%
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net			$ 48,900
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt			$ 34,800
Roswell City Walk [Member]
Business Acquisition [Line Items]
Number of Real Estate Properties, Fee Simple		320
Payments to Acquire Interest in Joint Venture		$ 25,500
Business Acquisition, Percentage of Voting Interests Acquired		98.00%
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net		$ 76,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt		$ 51,000
Phase II [Member]
Business Acquisition [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest												100.00%
Number of Real Estate Properties, Fee Simple																	15
Lansbrook [Member]
Business Acquisition [Line Items]
Business Acquisition Indirect Ownership, Amount											$ 3,700							$ 3,700
Fund III [Member]
Business Acquisition [Line Items]
Purchase Of Interest In Joint Venture										4.00%
Phase II Units [Member]
Business Acquisition [Line Items]
Payments to Acquire Interest in Joint Venture										$ 100
Minimum [Member] | Lansbrook [Member]
Business Acquisition [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest											76.80%
Maximum [Member] | Lansbrook [Member]
Business Acquisition [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest											90.00%
Park Kingston Phase I Units [Member]
Business Acquisition [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest																46.95%
Business Acquisition Indirect Ownership, Amount														$ 6,500		$ 6,300
Park Kingston Phase I Units [Member] | Phase I [Member]
Business Acquisition [Line Items]
Business Acquisition Indirect Ownership, Amount																27,850
Park Kingston Phase I Units [Member] | Minimum [Member]
Business Acquisition [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest														46.95%
Park Kingston Phase I Units [Member] | Maximum [Member]
Business Acquisition [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest														96.00%
Park Kingston Phase I Units [Member] | Senior Secured Mortgage Loan [Member]
Business Acquisition [Line Items]
Business Acquisition Indirect Ownership, Amount																$ 15,250
Fox Hill [Member]
Business Acquisition [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest															85.27%
Number of Real Estate Properties, Fee Simple															288
Business Acquisition Indirect Ownership, Amount														$ 1,100	$ 10,200
Fox Hill [Member] | Minimum [Member]
Business Acquisition [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest														85.27%
Business Acquisition Indirect Ownership, Amount															38,150
Fox Hill [Member] | Maximum [Member]
Business Acquisition [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest														94.62%
Fox Hill [Member] | Senior Secured Mortgage Loan [Member]
Business Acquisition [Line Items]
Business Acquisition Indirect Ownership, Amount															$ 26,710
Ashton I [Member]
Business Acquisition [Line Items]
Number of Real Estate Properties, Fee Simple																					151		322
Business Acquisition Indirect Ownership, Amount																							$ 13,500
Equity Method Investment, Ownership Percentage																							0.00%
Ashton I [Member] | Founded [Member]
Business Acquisition [Line Items]
Business Acquisition Indirect Ownership, Amount																							$ 44,750
Ashton I [Member] | Senior Secured Mortgage Loan [Member]
Business Acquisition [Line Items]
Business Acquisition Indirect Ownership, Amount																							$ 31,900
ARIUM Palms [Member]
Business Acquisition [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest													95.00%
Number of Real Estate Properties, Fee Simple													252
Business Acquisition Indirect Ownership, Amount													$ 13,000
ARIUM Palms [Member] | Founded [Member]
Business Acquisition [Line Items]
Business Acquisition Indirect Ownership, Amount													37,000
ARIUM Palms [Member] | Senior Secured Mortgage Loan [Member]
Business Acquisition [Line Items]
Business Acquisition Indirect Ownership, Amount													$ 25,000
Ashton II [Member]
Business Acquisition [Line Items]
Business Acquisition Indirect Ownership, Amount																					$ 21,800
Ashton II [Member] | Senior Secured Mortgage Loan [Member]
Business Acquisition [Line Items]
Business Acquisition Indirect Ownership, Amount																					$ 15,300
Sorrel [Member]
Business Acquisition [Line Items]
Number of Real Estate Properties, Fee Simple																				320		322
Business Acquisition Indirect Ownership, Amount																				$ 47,000		$ 55,300
Long-term Investments, Total																				$ 15,900		17,700
Equity Method Investment, Ownership Percentage																				95.00%
Sorrel [Member] | Senior Secured Mortgage Loan [Member]
Business Acquisition [Line Items]
Business Acquisition Indirect Ownership, Amount																				$ 32,600		$ 38,700
Sovereign [Member]
Business Acquisition [Line Items]
Number of Real Estate Properties, Fee Simple																						352
Business Acquisition Indirect Ownership, Amount																				39,300		$ 44,400
Long-term Investments, Total																						15,200
Sovereign [Member] | Senior Secured Mortgage Loan [Member]
Business Acquisition [Line Items]
Business Acquisition Indirect Ownership, Amount																				$ 26,900		$ 28,900
Sorrel and Sovereign [Member]
Business Acquisition [Line Items]
Equity Method Investment, Ownership Percentage																						95.00%
Citation Club Apartments [Member]
Business Acquisition [Line Items]
Number of Real Estate Properties, Fee Simple																				368
Long-term Investments, Total																				$ 13,600
Preserve At Henderson Beach [Member]
Business Acquisition [Line Items]
Number of Real Estate Properties, Fee Simple						340
Business Acquisition Indirect Ownership, Amount						$ 53,700
Long-term Investments, Total						17,200
Preserve At Henderson Beach [Member] | Senior Secured Mortgage Loan [Member]
Business Acquisition [Line Items]
Business Acquisition Indirect Ownership, Amount						$ 37,500
ARIUM Westside Atlanta GA [Member]
Business Acquisition [Line Items]
Number of Real Estate Properties, Fee Simple					336
Long-term Investments, Total					$ 22,200
Equity Method Investment, Ownership Percentage					90.00%
Business Combination, Consideration Transferred					$ 74,500
Mortgage Loans on Real Estate, Carrying Amount of Mortgages					$ 52,200
ARIUM Pine Lakes [Member]
Business Acquisition [Line Items]
Number of Real Estate Properties, Fee Simple									320
Payments to Acquire Interest in Joint Venture									$ 11,300
Business Acquisition, Percentage of Voting Interests Acquired									85.00%
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net									$ 38,300
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt									$ 27,000
Legacy At Southpark [Member]
Business Acquisition [Line Items]
Number of Real Estate Properties, Fee Simple								250
Payments to Acquire Interest in Joint Venture								$ 10,400
Business Acquisition, Percentage of Voting Interests Acquired								90.00%
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net								$ 36,800
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt								$ 26,500
Vickers Village [Member]
Business Acquisition [Line Items]
Number of Real Estate Properties, Fee Simple							79
Business Acquisition, Percentage of Voting Interests Acquired							80.00%
Payments To Acquire Equity Method Investments							$ 8,500
Crescent Perimeter [Member]
Business Acquisition [Line Items]
Number of Real Estate Properties, Fee Simple	320
Business Acquisition, Percentage of Voting Interests Acquired	60.00%
Payments To Acquire Equity Method Investments	$ 15,200