Other Assets, Accrued Expenses and Other Liabilities (Detail) $ in Millions	Jun. 30, 2019 USD ($) Lot	Oct. 01, 2018 USD ($)	Sep. 30, 2018 USD ($)
Segment Reporting Information [Line Items]
Receivables, net	$ 1.4		$ 2.7
Prepaid expenses	4.0		3.1
Land purchase contract deposits	7.4		4.1
Intangible assets	0.0		0.5
Other assets	5.7		5.0
Total Other assets	18.5		15.4
Accrued employee compensation and benefits	5.6		6.7
Accrued property taxes	1.8		1.7
Accrued interest	7.6		0.4
Contract liabilities	9.9	$ 6.4	0.0
Deferred income	9.4		11.6
Other accrued expenses	30.2		27.2
Other liabilities	2.9		2.0
Total Accrued expenses and other liabilities	$ 67.4		$ 49.6
Number of Units in Real Estate Property | Lot	37,400
Land and Land Improvements [Member] | D.R. Horton, Inc. [Member]
Segment Reporting Information [Line Items]
Number of Units in Real Estate Property | Lot	382