Income Taxes (Summary of Income Tax Contingencies) (Details) - USD ($)	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits, beginning of year	$ 10,900,000	$ 9,500,000	$ 9,400,000
Additions based on prior year tax positions and acquisitions	2,700,000	1,400,000	1,300,000
Reductions for prior year tax positions	0	0	0
Settlements with taxing authorities/statute expirations	(800,000)	0	(1,200,000)
Unrecognized tax benefits, end of year	$ 12,800,000	$ 10,900,000	$ 9,500,000