Acquisitions - Other Information for Fiscal 2018 Acquisitions (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Business Acquisition [Line Items]
Goodwill	$ 257,582	$ 300,527	$ 299,248
GPMX
Business Acquisition [Line Items]
Cash and cash equivalents			2,560
Earning assets			17,247
Other assets			2,145
Property and equipment, intangible assets, deferred taxes and other assets, net			11,671
Goodwill			34,816
Accounts payable, deferred taxes and other liabilities			(6,723)
Total consideration			61,716
All Other
Business Acquisition [Line Items]
Cash and cash equivalents			0
Earning assets			8,347
Other assets			3,737
Property and equipment, intangible assets, deferred taxes and other assets, net			13,678
Goodwill			7,770
Accounts payable, deferred taxes and other liabilities			1,621
Total consideration			$ 35,153