Income Taxes (Details) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Effective income tax rate	37.50%	47.00%	38.50%	65.80%
Nondeductible expense, share-based compensation cost, amount		$ 10,500,000		$ 10,500,000
Reserve for uncertain income tax positions	$ 0		$ 0		$ 0