Acquisitions	3 Months Ended
Dec. 31, 2012
Acquisitions [Abstract]
Business Combination Disclosure [Text Block]	Acquisitions Tradewire On December 12, 2012, the Company finalized an agreement in which Tradewire Securities, LLC, a Miami-based securities broker-dealer servicing customers throughout Latin America and a wholly-owned subsidiary of Tradewire Group Ltd., transferred its institutional accounts to INTL FCStone Inc.'s broker-dealer subsidiary, INTL FCStone Securities. Tradewire Securities, LLC provided global brokerage services to a wide range of customers, including hedge funds, pension funds, broker-dealers and banks located in Latin America, Caribbean, North America and Europe. Additionally, as part of the transaction, the Company hired more than 20 professional staff from Tradewire Securities, LLC's securities broker-dealer business based in Miami, Florida. The consideration to be paid for the acquisition of institutional accounts from Tradewire Securities, LLC consists of three annual contingent payments and a final contingent payment and is estimated to be $3.1 million as of December 31, 2012. The purchase price for the acquisition is not expected to be material to the condensed consolidated financial statements. The allocation of the purchase price to separately identifiable intangible assets is preliminary in nature, and is subject to adjustment as additional information is obtained, including but not limited to the calculation of the contingent consideration and valuation of separately identifiable intangible assets. These calculations and valuations of any identified intangible assets are subject to change within the measurement period (up to one year from the acquisition date) as valuations are finalized. When the valuations are finalized, any changes may result in adjustments to separately identifiable intangible assets and goodwill. Any adjustments made to the valuations are not expected to be material. The intangible assets recognized in this transaction of $3.1 million were assigned to the SEC segment.

Acquisitions

3 Months Ended

Dec. 31, 2012

Business Combination Disclosure [Text Block]

Acquisitions

Tradewire

On December 12, 2012, the Company finalized an agreement in which Tradewire Securities, LLC, a Miami-based securities broker-dealer servicing customers throughout Latin America and a wholly-owned subsidiary of Tradewire Group Ltd., transferred its institutional accounts to INTL FCStone Inc.'s broker-dealer subsidiary, INTL FCStone Securities. Tradewire Securities, LLC provided global brokerage services to a wide range of customers, including hedge funds, pension funds, broker-dealers and banks located in Latin America, Caribbean, North America and Europe. Additionally, as part of the transaction, the Company hired more than 20 professional staff from Tradewire Securities, LLC's securities broker-dealer business based in Miami, Florida.

The consideration to be paid for the acquisition of institutional accounts from Tradewire Securities, LLC consists of three annual contingent payments and a final contingent payment and is estimated to be $3.1 million as of December 31, 2012. The purchase price for the acquisition is not expected to be material to the condensed consolidated financial statements. The allocation of the purchase price to separately identifiable intangible assets is preliminary in nature, and is subject to adjustment as additional information is obtained, including but not limited to the calculation of the contingent consideration and valuation of separately identifiable intangible assets. These calculations and valuations of any identified intangible assets are subject to change within the measurement period (up to one year from the acquisition date) as valuations are finalized. When the valuations are finalized, any changes may result in adjustments to separately identifiable intangible assets and goodwill. Any adjustments made to the valuations are not expected to be material. The intangible assets recognized in this transaction of $3.1 million were assigned to the SEC segment.