Debt (Schedule of Lines of Credit Outstanding) (Details) - USD ($) $ in Thousands	Sep. 01, 2017	Mar. 06, 2017	May 03, 2016	Dec. 15, 2015	Sep. 30, 2017	Dec. 31, 2016	Dec. 15, 2016	Aug. 31, 2016	Jul. 30, 2015
Line of Credit Facility [Line Items]
Long-term Line of Credit					$ 95,000	$ 75,000
JohnsCreekCarrolltonAllen [Member] | Inwood National Bank [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity			$ 50,000						$ 50,000
Long-term Line of Credit					$ 20,000	15,000
BorrowingBaseLimitationTotalValueOfland			50.00%
BorrowingBaseLimitationTotalValueOfLotsOwned			65.00%
MaximumValueOfLandUsedWhenCalculatingBorrowingBase			65.00%
Line of Credit Facility, Interest Rate at Period End					4.30%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage			0.25%
Other Assets [Member] | JohnsCreekCarrolltonAllen [Member] | Inwood National Bank [Member]
Line of Credit Facility [Line Items]
Payments of Debt Issuance Costs			$ 100
Minimum [Member] | JohnsCreekCarrolltonAllen [Member] | Inwood National Bank [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage									4.00%
Maximum [Member] | JohnsCreekCarrolltonAllen [Member] | Inwood National Bank [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage									18.00%
Unsecured Debt [Member] | Unsecured Revolving Credit Facility [Member] | Citibank, N.A. and Credit Suisse AG, CAyman Islands Branch [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity				$ 75,000
Long-term Line of Credit				$ 40,000	$ 75,000	$ 60,000
Line of Credit Facility, Interest Rate at Period End					3.70%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage				0.45%
Unrestricted Cash Borrowing Base Limitation				100.00%
Borrowing Base Limitation for Unrestricted Cash				$ 15,000
Book Value of Model Homes Borrowing Base				85.00%
Book Value of Finished Lots and Land Under Development				65.00%
Book Value of Entitled Land				50.00%
Unsecured Debt [Member] | Unsecured Revolving Credit Facility [Member] | Flagstar Bank [Member]
Line of Credit Facility [Line Items]
Long-term Line of Credit	$ 70,000	$ 35,000						$ 20,000
Unsecured Debt [Member] | Unsecured Revolving Credit Facility [Member] | Citibank, N.A. [Member]
Line of Credit Facility [Line Items]
Long-term Line of Credit				$ 25,000			$ 35,000
Unsecured Debt [Member] | Unsecured Revolving Credit Facility [Member] | Credit Suisse AG, Cayman Islands Branch [Member]
Line of Credit Facility [Line Items]
Long-term Line of Credit	25,000			$ 15,000
Unsecured Debt [Member] | Unsecured Revolving Credit Facility [Member] | Citibank, N.A., Credit Suisse AG, Cayman Islands Branch,an d Flagstar Bank [Member] [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	200,000							110,000
Long-term Line of Credit	130,000	85,000					$ 70,000	$ 60,000
Line of Credit Facility, Upfront Fee on Extended Commitments							0.15%
Unsecured Debt [Member] | Other Assets [Member] | Unsecured Revolving Credit Facility [Member] | Flagstar Bank [Member]
Line of Credit Facility [Line Items]
Payments of Debt Issuance Costs		$ 100
Unsecured Debt [Member] | Other Assets [Member] | Unsecured Revolving Credit Facility [Member] | Citibank, N.A., Credit Suisse AG, Cayman Islands Branch,an d Flagstar Bank [Member] [Member]
Line of Credit Facility [Line Items]
Payments of Debt Issuance Costs	$ 400
Unsecured Debt [Member] | Base Rate [Member] | Unsecured Revolving Credit Facility, Base Rate Advances [Member] | Citibank, N.A. and Credit Suisse AG, CAyman Islands Branch [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate				1.50%
Unsecured Debt [Member] | Federal Funds Effective Swap Rate [Member] | Unsecured Revolving Credit Facility, Base Rate Advances [Member] | Citibank, N.A. and Credit Suisse AG, CAyman Islands Branch [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate				0.50%
Unsecured Debt [Member] | London Interbank Offered Rate (LIBOR) [Member] | Unsecured Revolving Credit Facility, Base Rate Advances [Member] | Citibank, N.A. and Credit Suisse AG, CAyman Islands Branch [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate				1.00%
Unsecured Debt [Member] | London Interbank Offered Rate (LIBOR) [Member] | Unsecured Revolving Credit Facility, Eurodollar Rate Advances [Member] | Citibank, N.A. and Credit Suisse AG, CAyman Islands Branch [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate				2.50%