Commodity and Other Repurchase Agreements (Notes)	12 Months Ended
Sep. 30, 2015
Commodity and Other Repurchase Agreements [Abstract]
Repurchase Agreements, Resale Agreements, Securities Borrowed, and Securities Loaned Disclosure [Text Block]	Commodity and Other Repurchase Agreements and Collateralized Transactions The Company’s outstanding notes receivable in connection with the sale/repurchase agreements, whereby the customers sell certain commodity inventory and agree to repurchase the commodity inventory at a future date at either a fixed or floating rate, as of September 30, 2015 and 2014 was $26.7 million and $20.6 million, respectively. The obligations outstanding related to commodities sold under repurchase agreements that are recorded in ‘lenders under loans’ as of September 30, 2015 and 2014 were $10.0 million and $7.5 million, respectively. The Company enters into securities purchased under agreements to resell and payables under repurchase agreements primarily to finance financial instruments, acquire securities to cover short positions or to acquire securities for settlement. These agreements are recorded at their contractual amounts plus accrued interest. The related interest is recorded in the consolidated income statement as interest income or interest expense, as applicable. In connection with these agreements and transactions, it is the policy of the Company to receive or pledge cash or securities to adequately collateralize such agreements and transactions in accordance with general industry guidelines and practices. The value of the collateral is valued daily and the Company may require counterparties to deposit additional collateral or return collateral pledged, when appropriate. The carrying amounts of these agreements and transactions approximate fair value due to their short-term nature and the level of collateralization. The Company pledges financial instruments owned to collateralize repurchase agreements. At September 30, 2015, on a settlement date basis, financial instruments owned of $170.7 million were pledged as collateral under repurchase agreements. The counterparty has the right to repledge the collateral in connection with these transactions. These financial instruments owned have been pledged as collateral and have been parenthetically disclosed on the consolidated balance sheet. In addition, as of September 30, 2015, the Company pledged settlement date securities owned of $843.5 million and securities received under reverse repurchase agreements of $84.3 million to cover collateral for tri-party repurchase agreements. For these securities, the counterparty does not have the right to sell or repledge the collateral. At September 30, 2015, the Company has accepted collateral that it is permitted by contract or custom to sell or repledge. This collateral consists primarily of securities received in reverse repurchase agreements. The fair value of such collateral at September 30, 2015, was $396.6 million of which $315.3 million was used to cover securities sold short which are recorded in financial instruments sold, not yet purchased on the consolidated balance sheet. In the normal course of business, this collateral is used by the Company to cover financial instruments sold, not yet purchased and to obtain financing in the form of repurchase agreements. At September 30, 2015, substantially all of the above collateral had been delivered against financial instruments sold, not yet purchased or repledged by the Company to obtain financing.

Commodity and Other Repurchase Agreements and Collateralized Transactions

The Company’s outstanding notes receivable in connection with the sale/repurchase agreements, whereby the customers sell certain commodity inventory and agree to repurchase the commodity inventory at a future date at either a fixed or floating rate, as of September 30, 2015 and 2014 was $26.7 million and $20.6 million, respectively.

The obligations outstanding related to commodities sold under repurchase agreements that are recorded in ‘lenders under loans’ as of September 30, 2015 and 2014 were $10.0 million and $7.5 million, respectively.

The Company enters into securities purchased under agreements to resell and payables under repurchase agreements primarily to finance financial instruments, acquire securities to cover short positions or to acquire securities for settlement. These agreements are recorded at their contractual amounts plus accrued interest. The related interest is recorded in the consolidated income statement as interest income or interest expense, as applicable. In connection with these agreements and transactions, it is the policy of the Company to receive or pledge cash or securities to adequately collateralize such agreements and transactions in accordance with general industry guidelines and practices. The value of the collateral is valued daily and the Company may require counterparties to deposit additional collateral or return collateral pledged, when appropriate. The carrying amounts of these agreements and transactions approximate fair value due to their short-term nature and the level of collateralization.

The Company pledges financial instruments owned to collateralize repurchase agreements. At September 30, 2015, on a settlement date basis, financial instruments owned of $170.7 million were pledged as collateral under repurchase agreements. The counterparty has the right to repledge the collateral in connection with these transactions. These financial instruments owned have been pledged as collateral and have been parenthetically disclosed on the consolidated balance sheet.

In addition, as of September 30, 2015, the Company pledged settlement date securities owned of $843.5 million and securities received under reverse repurchase agreements of $84.3 million to cover collateral for tri-party repurchase agreements. For these securities, the counterparty does not have the right to sell or repledge the collateral.

At September 30, 2015, the Company has accepted collateral that it is permitted by contract or custom to sell or repledge. This collateral consists primarily of securities received in reverse repurchase agreements. The fair value of such collateral at September 30, 2015, was $396.6 million of which $315.3 million was used to cover securities sold short which are recorded in financial instruments sold, not yet purchased on the consolidated balance sheet. In the normal course of business, this collateral is used by the Company to cover financial instruments sold, not yet purchased and to obtain financing in the form of repurchase agreements. At September 30, 2015, substantially all of the above collateral had been delivered against financial instruments sold, not yet purchased or repledged by the Company to obtain financing.