Income Taxes	6 Months Ended
Mar. 31, 2017
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The Company’s income tax expense for the three and six months ended March 31, 2017 was $124.7 million and $236.0 million, respectively, compared to $105.4 million and $189.0 million in the prior year periods. The effective tax rate was 35.2% and 35.1% for the three and six months ended March 31, 2017, respectively, compared to 35.1% and 34.9% in the prior year periods. The effective tax rate for all periods includes an expense for state income taxes, reduced by tax benefits for the domestic production activities deduction and federal energy tax credits. The Company previously filed three requests for advance consent for a change in tax accounting method with the Internal Revenue Service (IRS). The tax accounting method changes relate to the timing of income and expense recognition of certain items for tax purposes. In March 2017, the Company received consent agreements from the IRS regarding two of the three requests. The Company is currently in the process of analyzing these consent agreements and expects to request further clarification from the IRS. Once the consent agreements have been agreed to and signed by the Company, the estimated impact of the approved tax accounting method changes will be reflected in the consolidated financial statements, likely as of June 30, 2017. The impact on the consolidated balance sheet will be a reduction in income taxes payable and a corresponding reduction in deferred tax assets. These changes in tax accounting methods will not have a significant impact on the Company’s effective tax rate. At March 31, 2017 and September 30, 2016, the Company had deferred tax assets, net of deferred tax liabilities, of $461.9 million and $486.6 million, respectively, partially offset by a valuation allowance of $10.3 million. 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. When assessing the realizability of deferred tax assets, the Company considers whether it is more likely than not that some portion or all of its deferred tax assets will not be realized. The realization of deferred tax assets is dependent upon the generation of sufficient taxable income in future periods. The Company records a valuation allowance when it determines it is more likely than not that a portion of the deferred tax assets will not be realized. The valuation allowance for both periods relates to the Company’s state deferred tax assets for net operating loss (NOL) carryforwards. As of March 31, 2017, the Company believes it is more likely than not that a portion of its state NOL carryforwards will not be realized because some state NOL carryforward periods are too brief to realize the related deferred tax assets. 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.

INCOME TAXES

The Company’s income tax expense for the three and six months ended March 31, 2017 was $124.7 million and $236.0 million, respectively, compared to $105.4 million and $189.0 million in the prior year periods. The effective tax rate was 35.2% and 35.1% for the three and six months ended March 31, 2017, respectively, compared to 35.1% and 34.9% in the prior year periods. The effective tax rate for all periods includes an expense for state income taxes, reduced by tax benefits for the domestic production activities deduction and federal energy tax credits.

The Company previously filed three requests for advance consent for a change in tax accounting method with the Internal Revenue Service (IRS). The tax accounting method changes relate to the timing of income and expense recognition of certain items for tax purposes. In March 2017, the Company received consent agreements from the IRS regarding two of the three requests. The Company is currently in the process of analyzing these consent agreements and expects to request further clarification from the IRS. Once the consent agreements have been agreed to and signed by the Company, the estimated impact of the approved tax accounting method changes will be reflected in the consolidated financial statements, likely as of June 30, 2017. The impact on the consolidated balance sheet will be a reduction in income taxes payable and a corresponding reduction in deferred tax assets. These changes in tax accounting methods will not have a significant impact on the Company’s effective tax rate.

At March 31, 2017 and September 30, 2016, the Company had deferred tax assets, net of deferred tax liabilities, of $461.9 million and $486.6 million, respectively, partially offset by a valuation allowance of $10.3 million. 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.

When assessing the realizability of deferred tax assets, the Company considers whether it is more likely than not that some portion or all of its deferred tax assets will not be realized. The realization of deferred tax assets is dependent upon the generation of sufficient taxable income in future periods. The Company records a valuation allowance when it determines it is more likely than not that a portion of the deferred tax assets will not be realized. The valuation allowance for both periods relates to the Company’s state deferred tax assets for net operating loss (NOL) carryforwards. As of March 31, 2017, the Company believes it is more likely than not that a portion of its state NOL carryforwards will not be realized because some state NOL carryforward periods are too brief to realize the related deferred tax assets. 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.