Income Taxes - Text (Detail) - USD ($)			9 Months Ended	12 Months Ended
	Sep. 30, 2019	Oct. 05, 2017	Sep. 30, 2018	Sep. 30, 2019	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 1,600,000			$ 1,600,000
Federal statutory rate (benefit)			21.00%	21.00%	35.00%
Net operating loss carryforwards	15,100,000		$ 17,700,000	$ 15,100,000
Deferred Tax Assets, Valuation Allowance	(3,300,000)		(3,400,000)	(3,300,000)
Unrecognized Tax Benefits, Interest on Income Taxes Expense			0	0	$ 0
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	$ 0		$ 0	0	$ 0
D.R. Horton Merger Agreement [Member] | D.R. Horton, Inc. [Member]
Operating Loss Carryforwards [Line Items]
Sale of Stock, Percentage of Ownership after Transaction	66.00%	75.00%
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 11,400,000			11,400,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	3,700,000			3,700,000
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration	3,300,000			3,300,000
Deferred Tax Assets, Operating Loss Carryforwards, Not Subject to Expiration	$ 400,000			400,000
D.R. Horton, Inc. [Member] | Reimbursement From Parent [Member]
Operating Loss Carryforwards [Line Items]
Related Party Transaction, Amounts of Transaction				$ 400,000