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Income Taxes Income Tax Rate Reconciliation (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2017
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	24.50%	21.00%	24.50%	35.00%
Adjustments to reconcile to the effective tax rate:
State income taxes, net of federal benefit	4.50%	4.80%	5.60%	4.50%
Tax benefits from stock compensation	(0.30%)	(0.20%)	(1.40%)	(1.20%)
U.S. manufacturing deduction	0.00%	(1.70%)	0.00%	(1.60%)
Tax credits	(1.20%)	(1.10%)	(2.70%)	(1.00%)
Effective Income Tax Rate Reconciliation, GILTI, percent	0.60%	0.00%	1.20%	0.00%
FIN 48 statute release	(5.20%)	0.00%	(7.20%)	0.00%
Other	1.90%	1.90%	3.60%	(0.20%)
Walter Energy accrual	(0.40%)	0.00%	4.60%	0.00%
Effective Income Tax Rate Reconciliation, Transition Tax	0.00%	0.00%	(1.90%)	12.30%
Change in rate for deferred taxes	0.00%	0.00%	0.00%	(69.80%)
Effective income tax rate	20.90%	28.20%	22.70%	(32.10%)

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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