Intangible Assets Intangible Asset Additions (Details) $ in Millions	12 Months Ended
	Sep. 30, 2019 USD ($)
Business Acquisition [Line Items]
Indefinite-lived Intangible Assets Acquired	$ 2.7
Coininvest and European Precious Metals Trading [Member]
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired	2.6
Indefinite-lived Intangible Assets Acquired	2.1
Fillmore Advisors, LLC [Member]
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired	0.7
Akshay Financeware, Inc. Acquisition [Member]
Business Acquisition [Line Items]
Indefinite-lived Intangible Assets Acquired	$ 2.7