Income Taxes - Additional Information (Detail) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||||
---|---|---|---|---|---|---|
Oct. 05, 2017 |
Jun. 30, 2019 |
Jun. 30, 2018 |
Jun. 30, 2019 |
Jun. 30, 2018 |
Sep. 30, 2018 |
|
Effective income tax rate, percent | 18.00% | 1.00% | 20.00% | 268.00% | ||
Deferred Tax Assets, Net Of Deferred Tax Liabilities | $ 24.3 | $ 24.3 | $ 30.3 | |||
Valuation allowance, deferred tax asset, amount | 3.3 | 3.3 | $ 3.4 | |||
Unrecognized tax benefits | $ 1.1 | $ 1.1 | ||||
Majority Shareholder [Member] | D.R. Horton, Inc. [Member] | ||||||
Sale of Stock, Percentage of Ownership after Transaction | 75.00% |