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Related Party Transactions (Details)		1 Months Ended				3 Months Ended		12 Months Ended
Related Party Transactions (Details)	Mar. 01, 2016 USD ($) townhome Lots	Feb. 28, 2017 USD ($)	Sep. 30, 2016	Jun. 30, 2016 USD ($)	Nov. 30, 2015 USD ($) townhome Lots	Mar. 31, 2017 USD ($) townhome Lots board_seat	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 townhome Lots
Related Party Transaction [Line Items]
Interest incurred						$ 893,000	$ 708,000
Ownership percentage by parent						50.00%
Ownership percentage by noncontrolling owners						50.00%
Net income						$ 14,433,000		$ 16,913,000
Centre Living
Related Party Transaction [Line Items]
Percentage of voting interest						51.00%
Ownership percentage by parent						50.00%
Ownership percentage by noncontrolling owners						50.00%
Percent of centre living operations consolidated						100.00%
Net income						$ 200,000		300,000
The Parc at Cogburn [Member] \| Investee [Member]
Related Party Transaction [Line Items]
Number of Real Estate Properties \| Lots						16				11
Number of Units in Real Estate Property \| townhome										19
Payments to acquire real estate						$ 500,000		300,000	$ 1,800,000
Landunder purchase options expected purchase payments						500,000
Glens at Sugarloaf [Member] \| Investee [Member]
Related Party Transaction [Line Items]
Number of Real Estate Properties \| Lots					12
Number of Units in Real Estate Property \| townhome	80				92
Deposit paid for purchase of real estate					$ 0
Payments to acquire real estate	$ 4,800,000								$ 1,000,000
Academy Street [Member]
Related Party Transaction [Line Items]
Company capital contributions						9,400,000
Capital contributions made						500,000		11,200,000
Payment for capital contributions						400,000		9,000,000
Academy Street [Member] \| Investee [Member]
Related Party Transaction [Line Items]
Ownership percentage by parent	80.00%
Ownership percentage by noncontrolling owners	20.00%
Total estimated Capital Contributions						11,800,000
Number of Real Estate Properties \| Lots	83
Suwanee Station [Member]
Related Party Transaction [Line Items]
Company capital contributions						1,000,000
Capital contributions made						$ 0		1,800,000
Payment for capital contributions								900,000
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest						80.00%
BoardSeatsHeld \| board_seat						2
BoardSeatsAvailable \| board_seat						3
Suwanee Station [Member] \| Investee [Member]
Related Party Transaction [Line Items]
Total estimated Capital Contributions						$ 2,000,000
Number of Real Estate Properties \| townhome	73
Equity Method Investment, Ownership Percentage	50.00%
Equity method investment, ownership percentage by partner	50.00%
Dunwoody Towneship [Member] \| Investee [Member]
Related Party Transaction [Line Items]
Number of Real Estate Properties \| Lots						14
Number of Units in Real Estate Property \| townhome						40
Deposit paid for purchase of real estate				$ 0
Payments to acquire real estate						$ 800,000		$ 1,800,000
Expected purchase payments in 2017						1,000,000
Expected purchase payments in 2018						$ 1,700,000
Developed Lots \| Centre Living
Related Party Transaction [Line Items]
Number of Real Estate Properties \| Lots						1
Proceeds from sale of developed lot				400,000
Cost of developed lot sold				$ 300,000
Contract price employee discount premium			13.00%
Development in Process						$ 400,000
Accounts Receivable, Related Parties						$ 40,569
townhome [Domain] \| Chief Financial Officer [Member]
Related Party Transaction [Line Items]
Contract price employee discount premium		13.00%
townhome [Domain] \| Officer [Member]
Related Party Transaction [Line Items]
Contract price employee discount premium		13.00%
Richard A. Costello [Member] \| Centre Living
Related Party Transaction [Line Items]
Related party deposit liabilities		$ 110,000
Estimated purchase price to acquire residential real estate		525,000
Jed Dolson [Member] \| Centre Living
Related Party Transaction [Line Items]
Related party deposit liabilities		110,000
Estimated purchase price to acquire residential real estate		$ 475,000