Commitments and Contingencies - Contingencies and Litigation (Details) $ in Millions	Nov. 16, 2018 account	Sep. 30, 2019 USD ($)
Other Commitments [Line Items]
Loss contingency, range of possible loss, portion not accrued		$ 29.0
Maximum amount of individual accounts receivable account		$ 1.4
StoneX Financial [Member]
Other Commitments [Line Items]
Number of accounts \| account	300

The difference between the maximum amount of estimated loss and the amount recorded as of the balance sheet date.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 05
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=99385795&loc=d3e12631-108344

Name:	us-gaap_LossContingencyRangeOfPossibleLossPortionNotAccrued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant