Income Taxes	6 Months Ended
Mar. 31, 2018
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The Company’s income tax expense for the three and six months ended March 31, 2018 was $94.0 million and $296.4 million, respectively, compared to $124.7 million and $236.0 million in the prior year periods. The effective tax rate was 21.1% and 35.5% for the three and six months ended March 31, 2018, respectively, compared to 35.2% and 35.1% in the prior year periods. The effective tax rates for the three and six months ended March 31, 2018 reflect the impact of the Tax Cuts and Jobs Act (Tax Act), which was enacted into law on December 22, 2017, an excess tax benefit related to stock-based compensation and the enactment of the Bipartisan Budget Act of 2018, which retroactively extended the expiration date of the federal energy efficient home credit from December 31, 2016 until December 31, 2017. The effective tax rates for all periods include an expense for state income taxes, reduced by tax benefits for the domestic production activities deduction. The Tax Act reduced the corporate tax rate from 35% to 21% for all corporations effective January 1, 2018. For fiscal year companies, the change in law requires the application of a blended tax rate in the year of change, which for the Company is 24.5% for the fiscal year ending September 30, 2018. Thereafter, the applicable statutory tax rate is 21%. ASC 740 requires all companies to reflect the effects of the new law in the period in which the law was enacted. Accordingly, the Company reduced the statutory tax rate that applied to its year-to-date earnings from 35% to 24.5%. In addition, the Company remeasured its deferred tax assets and liabilities for the tax law change, which resulted in additional income tax expense of $108.7 million recognized during the three months ended December 31, 2017. The initial remeasurement was the Company’s best estimate based on the information available at the time. Adjustments to deferred tax expense will continue to be recognized to the extent the actual timing of future deferred tax reversals and originations differ from original estimates and will be recorded in subsequent quarters until the filing of the Company’s federal tax return. Any required adjustment will be reflected as a discrete expense or benefit in the quarter that it is identified, as allowed by SEC Staff Accounting Bulletin No. 118. For the three months ended March 31, 2018, no significant adjustments to the remeasurement of the Company’s deferred tax accounts were recognized. No other tax law changes as a result of the Tax Act are expected to have a significant impact on the Company’s financial statements. The Company’s deferred tax assets, net of deferred tax liabilities, were $245.8 million at March 31, 2018 compared to $376.2 million at September 30, 2017. On October 5, 2017, the Company acquired 75% of the outstanding shares of Forestar. The Company recorded goodwill of $29.2 million, which is not deductible for income tax purposes. Deferred tax assets of $20.4 million and a valuation allowance of $20.1 million were recorded as a result of the acquisition. At the acquisition date, the Company considered whether it was more likely than not that some portion or all of Forestar’s deferred tax assets would not be realized. In making such judgment, the Company considered all available positive and negative evidence. The Company determined that Forestar’s cumulative losses in recent years were a significant piece of negative evidence that outweighed the positive evidence, and a valuation allowance was recorded. In addition to the valuation allowance relating to Forestar’s deferred tax assets, the Company has a valuation allowance related to state deferred tax assets for net operating loss (NOL) carryforwards. The valuation allowance was recorded because it is more likely than not that a portion of the state NOL carryforwards will not be realized because some state NOL carryforward periods are too brief to realize the related deferred tax asset. The Company’s total valuation allowance was $25.9 million at March 31, 2018 and $11.2 million at September 30, 2017. The Company will continue to evaluate both the positive and negative evidence in determining the need for a valuation allowance with respect to its remaining state NOL carryforwards and Forestar’s deferred tax assets. Any reversal of the valuation allowance in future periods will impact the Company’s effective tax rate. The accounting for deferred taxes is based upon estimates of future results. Differences between the anticipated and actual outcomes of these future results could have a material impact on the Company’s consolidated results of operations or financial position. Also, changes in existing federal and state tax laws and tax rates could affect future tax results and the valuation of the Company’s deferred tax assets.

INCOME TAXES

The Company’s income tax expense for the three and six months ended March 31, 2018 was $94.0 million and $296.4 million, respectively, compared to $124.7 million and $236.0 million in the prior year periods. The effective tax rate was 21.1% and 35.5% for the three and six months ended March 31, 2018, respectively, compared to 35.2% and 35.1% in the prior year periods. The effective tax rates for the three and six months ended March 31, 2018 reflect the impact of the Tax Cuts and Jobs Act (Tax Act), which was enacted into law on December 22, 2017, an excess tax benefit related to stock-based compensation and the enactment of the Bipartisan Budget Act of 2018, which retroactively extended the expiration date of the federal energy efficient home credit from December 31, 2016 until December 31, 2017. The effective tax rates for all periods include an expense for state income taxes, reduced by tax benefits for the domestic production activities deduction.

The Tax Act reduced the corporate tax rate from 35% to 21% for all corporations effective January 1, 2018. For fiscal year companies, the change in law requires the application of a blended tax rate in the year of change, which for the Company is 24.5% for the fiscal year ending September 30, 2018. Thereafter, the applicable statutory tax rate is 21%. ASC 740 requires all companies to reflect the effects of the new law in the period in which the law was enacted. Accordingly, the Company reduced the statutory tax rate that applied to its year-to-date earnings from 35% to 24.5%. In addition, the Company remeasured its deferred tax assets and liabilities for the tax law change, which resulted in additional income tax expense of $108.7 million recognized during the three months ended December 31, 2017. The initial remeasurement was the Company’s best estimate based on the information available at the time. Adjustments to deferred tax expense will continue to be recognized to the extent the actual timing of future deferred tax reversals and originations differ from original estimates and will be recorded in subsequent quarters until the filing of the Company’s federal tax return. Any required adjustment will be reflected as a discrete expense or benefit in the quarter that it is identified, as allowed by SEC Staff Accounting Bulletin No. 118. For the three months ended March 31, 2018, no significant adjustments to the remeasurement of the Company’s deferred tax accounts were recognized. No other tax law changes as a result of the Tax Act are expected to have a significant impact on the Company’s financial statements. The Company’s deferred tax assets, net of deferred tax liabilities, were $245.8 million at March 31, 2018 compared to $376.2 million at September 30, 2017.

On October 5, 2017, the Company acquired 75% of the outstanding shares of Forestar. The Company recorded goodwill of $29.2 million, which is not deductible for income tax purposes. Deferred tax assets of $20.4 million and a valuation allowance of $20.1 million were recorded as a result of the acquisition. At the acquisition date, the Company considered whether it was more likely than not that some portion or all of Forestar’s deferred tax assets would not be realized. In making such judgment, the Company considered all available positive and negative evidence. The Company determined that Forestar’s cumulative losses in recent years were a significant piece of negative evidence that outweighed the positive evidence, and a valuation allowance was recorded.

In addition to the valuation allowance relating to Forestar’s deferred tax assets, the Company has a valuation allowance related to state deferred tax assets for net operating loss (NOL) carryforwards. The valuation allowance was recorded because it is more likely than not that a portion of the state NOL carryforwards will not be realized because some state NOL carryforward periods are too brief to realize the related deferred tax asset. The Company’s total valuation allowance was $25.9 million at March 31, 2018 and $11.2 million at September 30, 2017. The Company will continue to evaluate both the positive and negative evidence in determining the need for a valuation allowance with respect to its remaining state NOL carryforwards and Forestar’s deferred tax assets. Any reversal of the valuation allowance in future periods will impact the Company’s effective tax rate.

The accounting for deferred taxes is based upon estimates of future results. Differences between the anticipated and actual outcomes of these future results could have a material impact on the Company’s consolidated results of operations or financial position. Also, changes in existing federal and state tax laws and tax rates could affect future tax results and the valuation of the Company’s deferred tax assets.