Acquisitions and Disposals (Notes)	12 Months Ended
Sep. 30, 2014
Business Combinations [Abstract]
Business Combination Disclosure [Text Block]	Acquisitions and Disposals Acquisitions in Fiscal 2014 The Company’s consolidated financial statements include the operating results of the acquired businesses from the dates of acquisition. The total amount of goodwill and intangible assets, in connection with the current year acquisition, that is expected to be deductible for tax purposes is $0.5 million as of September 30, 2014. Forward Insight Commodities LLC In an acquisition agreement dated April 2, 2014, the Company’s wholly owned subsidiary, FCStone Group, Inc. (“FCG”), agreed to acquire all of the outstanding member interests of Forward Insight Commodities, LLC (“FIC”). FIC is a brokerage firm focused on the structuring and execution of transactions in the energy derivative space. The consideration to be paid for the acquisition consists of contingent payments based on the pre-tax earnings of the business for the twelve month period following the acquisition and is estimated to be $0.5 million as of September 30, 2014. The purchase price for the acquisition is not material to the 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 $0.5 million were assigned to the Clearing and Execution Services segment and are being amortized over a 12 month useful life. Acquisitions in Fiscal 2013 The Company’s consolidated financial statements include the operating results of the acquired businesses from the dates of acquisition. The total amount of goodwill and intangible assets, in connection with these acquisitions, that is expected to be deductible for tax purposes is $3.3 million as of September 30, 2014. Tradewire In December 2012, the Company acquired certain institutional accounts from Tradewire Securities, LLC (“Tradewire Securities”), a Miami-based securities broker-dealer servicing customers throughout Latin America and a wholly owned subsidiary of Tradewire Group Ltd. These accounts were transferred to INTL FCStone Inc.’s broker-dealer subsidiary, INTL FCStone Securities. As part of the transaction, the Company hired more than 20 professional staff from Tradewire Securities’ securities broker-dealer business based in Miami, Florida. These professionals provide global brokerage services to a wide range of customers, including hedge funds, pension funds, broker-dealers and banks located in Latin America, the Caribbean, North America and Europe. The consideration to be paid for the acquisition of institutional accounts from Tradewire Securities consists of three annual contingent payments and a final contingent payment and the original estimated present value was estimated to be $5.6 million as of the acquisition date. The purchase price for the acquisition is not expected to be material to the consolidated financial statements. The present value of the estimated total purchase price, including contingent consideration, is $3.3 million (see Note 11). The Company obtained a third-party valuation of the intangible assets and contingent liabilities, and allocated the purchase costs among identified intangible assets with determinable useful lives and goodwill. The goodwill and intangible asset recognized in this transaction of $2.8 million and $2.8 million, respectively, were assigned to the Securities segment. The intangible asset is being amortized over a 10 year useful life. Disposals in Fiscal 2013 Gletir Agente De Valores S.A. On February 28, 2013, the Company, through its subsidiaries INTL Netherlands B.V. and Gainvest Asset Management Ltda, entered into an agreement to sell all of its ownership interest in another subsidiary, Gletir Agente De Valores S.A. (“Gletir Agente”), to Gletir Financial Corp (the “Purchaser”). The Company sold the capital stock of Gletir Agente for $0.8 million. Gletir Agente had net assets of $0.6 million, which included $0.1 million of AOCI related to foreign currency translation, included in the consolidated balance sheet of the Company, at the time of the sale. The gain resulting from the sale price less the carrying amount of the net assets and the gain from the AOCI balance were recorded as components of other income on the consolidated income statement for the fiscal year ended ended September 30, 2013. Acquisitions in Fiscal 2012 During fiscal 2012, the Company acquired three businesses (Coffee Network, TRX Futures Limited and Aporte DTVM) and certain assets of the Metals Division of MF Global UK Limited, which were not considered significant on an individual or aggregate basis. The Company’s consolidated financial statements include the operating results of the acquired businesses from the dates of acquisition. These acquisitions resulted in the recognition of goodwill and intangible assets that is expected to be deductible for tax purposes of $0.7 million. Coffee Network In November 2011, the Company entered into an agreement to acquire 100% of the ownership interests in Coffee Network LLC (“Coffee Network”), an online news and analysis portal for the global coffee industry. Coffee Network provides up-to-the-minute news and in-depth analysis to subscribers around the globe from a network of correspondents and commodity analysts located in key coffee producing and consuming regions. These services provide a unique information solution to subscribers and a competitive advantage in today’s information-driven marketplace. The purchase price for the Coffee Network acquisition consists of an initial payment of $0.2 million, three additional annual contingent payments and a final contingent payment. The present value of the estimated total purchase price, including contingent consideration, is less than $0.3 million. The intangible assets recognized in this transaction were assigned to the Commercial Hedging segment. Purchase costs allocated to intangible assets with determinable useful lives are $0.2 million, which are being amortized over the remaining useful lives of the assets, and include customer relationships, websites and non-compete agreements (approximate two-year weighted-average useful life) and is deductible for tax purposes. MF Metals Team On November 25, 2011, INTL FCStone Ltd. Ltd, the Company’s wholly owned subsidiary in the United Kingdom (“UK”), arranged with the administrator of MF Global’s UK operations to acquire certain assets of the Metals Division of MF Global UK Limited (in special administration). As part of the arrangement, the Company received an assignment of customer accounts and customer account documentation. Additionally, as part of the transaction, the Company hired more than 50 professionals from MF Global’s metals trading business based in London. This business serves institutional investors and financial services firms in the Americas, Europe and the Asia-Pacific region. The Company has allocated equity capital to integrate these brokers and their customers into the Company’s operations, through a combination of increased regulatory capital to support the accounts of these customers and increased compensation and related personnel costs for the brokers. The amount of the required capital depends upon the activity in and balances of the customer accounts. The purchase price of the acquisition of certain assets from MF Global was $1.0 million. There was no contingent consideration associated with this transaction. The intangible assets recognized in this transaction were assigned to the Commercial Hedging segment. Purchase costs allocated to intangible assets with determinable useful lives are $0.5 million, which are being amortized over the remaining useful lives of the assets, and include customer relationships (approximate three-year weighted-average useful life). TRX Futures Limited On April 30, 2012, the Company’s wholly owned subsidiary in the UK, INTL Holding (UK) Limited, acquired 100% of the outstanding shares of TRX Futures Limited (“TRX”) from Neumann Gruppe GmbH. TRX is a London-based niche clearing firm for commercial coffee and cocoa customers, as well as energy and financial products. The purchase price was equal to the tangible net asset value of TRX, which was approximately $12.9 million. There are no additional payments remaining for this acquisition. The goodwill recognized in this transaction was assigned to the Commercial Hedging segment. Purchase costs allocated to goodwill of $0.3 million was calculated as the excess of the fair value of the consideration transferred over the fair value of the identified net assets acquired and liabilities assumed. Aporte DTVM In February 2012, the Company’s subsidiaries, INTL Participacoes LTDA and FCStone do Brasil, acquired 100% of the shares of Aporte DTVM. Following the acquisition, Aporte DTVM was renamed INTL FCStone DTVM Ltda. INTL FCStone DTVM is based in Brazil and is a broker-dealer regulated by the Central Bank of Brazil. The purchase price for the acquisition of the shares of Aporte DTVM was $1.5 million. There are no additional payments remaining for this acquisition. The goodwill recognized in this transaction was assigned to the Commercial Hedging segment. Purchase costs allocated to goodwill of $0.8 million was calculated as the excess of the fair value of the consideration transferred over the fair value of the identified net assets acquired and liabilities assumed.

Acquisitions and Disposals

Acquisitions in Fiscal 2014

The Company’s consolidated financial statements include the operating results of the acquired businesses from the dates of acquisition. The total amount of goodwill and intangible assets, in connection with the current year acquisition, that is expected to be deductible for tax purposes is $0.5 million as of September 30, 2014.

Forward Insight Commodities LLC

In an acquisition agreement dated April 2, 2014, the Company’s wholly owned subsidiary, FCStone Group, Inc. (“FCG”), agreed to acquire all of the outstanding member interests of Forward Insight Commodities, LLC (“FIC”). FIC is a brokerage firm focused on the structuring and execution of transactions in the energy derivative space.

The consideration to be paid for the acquisition consists of contingent payments based on the pre-tax earnings of the business for the twelve month period following the acquisition and is estimated to be $0.5 million as of September 30, 2014. The purchase price for the acquisition is not material to the 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 $0.5 million were assigned to the Clearing and Execution Services segment and are being amortized over a 12 month useful life.

Acquisitions in Fiscal 2013

The Company’s consolidated financial statements include the operating results of the acquired businesses from the dates of acquisition. The total amount of goodwill and intangible assets, in connection with these acquisitions, that is expected to be deductible for tax purposes is $3.3 million as of September 30, 2014.

Tradewire

In December 2012, the Company acquired certain institutional accounts from Tradewire Securities, LLC (“Tradewire Securities”), a Miami-based securities broker-dealer servicing customers throughout Latin America and a wholly owned subsidiary of Tradewire Group Ltd. These accounts were transferred to INTL FCStone Inc.’s broker-dealer subsidiary, INTL FCStone Securities. As part of the transaction, the Company hired more than 20 professional staff from Tradewire Securities’ securities broker-dealer business based in Miami, Florida. These professionals provide global brokerage services to a wide range of customers, including hedge funds, pension funds, broker-dealers and banks located in Latin America, the Caribbean, North America and Europe.

The consideration to be paid for the acquisition of institutional accounts from Tradewire Securities consists of three annual contingent payments and a final contingent payment and the original estimated present value was estimated to be $5.6 million as of the acquisition date. The purchase price for the acquisition is not expected to be material to the consolidated financial statements. The present value of the estimated total purchase price, including contingent consideration, is $3.3 million (see Note 11). The Company obtained a third-party valuation of the intangible assets and contingent liabilities, and allocated the purchase costs among identified intangible assets with determinable useful lives and goodwill. The goodwill and intangible asset recognized in this transaction of $2.8 million and $2.8 million, respectively, were assigned to the Securities segment. The intangible asset is being amortized over a 10 year useful life.

Disposals in Fiscal 2013

Gletir Agente De Valores S.A.

On February 28, 2013, the Company, through its subsidiaries INTL Netherlands B.V. and Gainvest Asset Management Ltda, entered into an agreement to sell all of its ownership interest in another subsidiary, Gletir Agente De Valores S.A. (“Gletir Agente”), to Gletir Financial Corp (the “Purchaser”). The Company sold the capital stock of Gletir Agente for $0.8 million. Gletir Agente had net assets of $0.6 million, which included $0.1 million of AOCI related to foreign currency translation, included in the consolidated balance sheet of the Company, at the time of the sale. The gain resulting from the sale price less the carrying amount of the net assets and the gain from the AOCI balance were recorded as components of other income on the consolidated income statement for the fiscal year ended ended September 30, 2013.

Acquisitions in Fiscal 2012

During fiscal 2012, the Company acquired three businesses (Coffee Network, TRX Futures Limited and Aporte DTVM) and certain assets of the Metals Division of MF Global UK Limited, which were not considered significant on an individual or aggregate basis. The Company’s consolidated financial statements include the operating results of the acquired businesses from the dates of acquisition.

These acquisitions resulted in the recognition of goodwill and intangible assets that is expected to be deductible for tax purposes of $0.7 million.

Coffee Network

In November 2011, the Company entered into an agreement to acquire 100% of the ownership interests in Coffee Network LLC (“Coffee Network”), an online news and analysis portal for the global coffee industry. Coffee Network provides up-to-the-minute news and in-depth analysis to subscribers around the globe from a network of correspondents and commodity analysts located in key coffee producing and consuming regions. These services provide a unique information solution to subscribers and a competitive advantage in today’s information-driven marketplace.

The purchase price for the Coffee Network acquisition consists of an initial payment of $0.2 million, three additional annual contingent payments and a final contingent payment. The present value of the estimated total purchase price, including contingent consideration, is less than $0.3 million. The intangible assets recognized in this transaction were assigned to the Commercial Hedging segment. Purchase costs allocated to intangible assets with determinable useful lives are $0.2 million, which are being amortized over the remaining useful lives of the assets, and include customer relationships, websites and non-compete agreements (approximate two-year weighted-average useful life) and is deductible for tax purposes.

MF Metals Team

On November 25, 2011, INTL FCStone Ltd. Ltd, the Company’s wholly owned subsidiary in the United Kingdom (“UK”), arranged with the administrator of MF Global’s UK operations to acquire certain assets of the Metals Division of MF Global UK Limited (in special administration). As part of the arrangement, the Company received an assignment of customer accounts and customer account documentation. Additionally, as part of the transaction, the Company hired more than 50 professionals from MF Global’s metals trading business based in London. This business serves institutional investors and financial services firms in the Americas, Europe and the Asia-Pacific region. The Company has allocated equity capital to integrate these brokers and their customers into the Company’s operations, through a combination of increased regulatory capital to support the accounts of these customers and increased compensation and related personnel costs for the brokers. The amount of the required capital depends upon the activity in and balances of the customer accounts.

The purchase price of the acquisition of certain assets from MF Global was $1.0 million. There was no contingent consideration associated with this transaction. The intangible assets recognized in this transaction were assigned to the Commercial Hedging segment. Purchase costs allocated to intangible assets with determinable useful lives are $0.5 million, which are being amortized over the remaining useful lives of the assets, and include customer relationships (approximate three-year weighted-average useful life).

TRX Futures Limited

On April 30, 2012, the Company’s wholly owned subsidiary in the UK, INTL Holding (UK) Limited, acquired 100% of the outstanding shares of TRX Futures Limited (“TRX”) from Neumann Gruppe GmbH. TRX is a London-based niche clearing firm for commercial coffee and cocoa customers, as well as energy and financial products. The purchase price was equal to the tangible net asset value of TRX, which was approximately $12.9 million. There are no additional payments remaining for this acquisition. The goodwill recognized in this transaction was assigned to the Commercial Hedging segment. Purchase costs allocated to goodwill of $0.3 million was calculated as the excess of the fair value of the consideration transferred over the fair value of the identified net assets acquired and liabilities assumed.

Aporte DTVM

In February 2012, the Company’s subsidiaries, INTL Participacoes LTDA and FCStone do Brasil, acquired 100% of the shares of Aporte DTVM. Following the acquisition, Aporte DTVM was renamed INTL FCStone DTVM Ltda. INTL FCStone DTVM is based in Brazil and is a broker-dealer regulated by the Central Bank of Brazil. The purchase price for the acquisition of the shares of Aporte DTVM was $1.5 million. There are no additional payments remaining for this acquisition. The goodwill recognized in this transaction was assigned to the Commercial Hedging segment. Purchase costs allocated to goodwill of $0.8 million was calculated as the excess of the fair value of the consideration transferred over the fair value of the identified net assets acquired and liabilities assumed.