Consolidated Cash Flows Statements (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities:
Net income	$ 19.3	$ 12.7	$ 34.7
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	8.0	7.2	4.7
Provision for bad debts and impairments	0.8	1.7	6.2
Deferred income taxes	(7.8)	(0.3)	1.8
Amortization of debt issuance costs and debt discount	1.2	1.7	1.6
Convertible debt interest settled in company stock upon conversion	0	0	0.2
Amortization of stock-based compensation expense	9.3	5.9	2.3
Loss on sale of property and equipment	0.4	0	0
Gain on disposition of affiliates	(0.4)	0	0
Gain on sale of exchange memberships and common stock	(9.1)	0	0
Gain on acquisition of INTL Provident	0	0	(0.4)
Changes in operating assets and liabilities, net:
Cash, securities and other assets segregated under federal and other regulations	(95.1)	(199.9)	(104.1)
Deposits and receivables from exchange-clearing organizations	42.3	(97.7)	(586.0)
Deposits and receivables from broker-dealers, clearing organizations, and counterparties	(53.4)	46.2	51.2
Receivable from customers, net	(23.7)	46.4	(39.1)
Notes receivable, net	66.6	(77.9)	2.9
Income taxes receivable	(0.2)	(3.1)	0.6
Financial instruments owned, at fair value	3.1	58.3	280.7
Physical commodities inventory	72.7	29.0	(35.6)
Other assets	4.3	(1.6)	(12.1)
Accounts payable and other accrued liabilities	(0.2)	10.6	30.8
Payable to customers	24.0	248.0	366.2
Payable to broker-dealers, clearing organizations and counterparties	(22.3)	35.9	(0.5)
Income taxes payable	0.5	0.3	0
Financial instruments sold, not yet purchased, at fair value	4.6	(215.5)	202.9
Net cash provided by (used in) operating activities	44.9	(92.1)	209.0
Cash flows from investing activities:
Deconsolidation of affiliates	0	0.4	0
Disposition of affiliates	(0.2)	0	0
Cash paid for other acquisitions, net	0	(11.7)	(9.3)
Purchase of exchange memberships and common stock	(0.3)	0	(3.4)
Sale of exchange memberships and common stock	10.1	0	1.3
Purchase of property and equipment	(4.9)	(8.7)	(10.1)
Net cash provided by (used in) investing activities	5.1	(20.0)	(21.5)
Cash flows from financing activities:
Net change in payable to lenders under loans	(157.2)	140.8	(37.5)
Payments related to earn-outs on acquisitions	(12.0)	(9.6)	(9.4)
Proceeds from issuance of senior unsecured notes	45.5	0	0
Repayment of subordinated debt	0	0	(0.5)
Share repurchase	(3.9)	(4.0)	0
Debt issuance costs	(3.7)	(0.3)	(2.4)
Exercise of stock options	1.5	1.9	1.4
Income tax benefit on stock options and awards	0.1	0.2	0
Net cash (used in) provided by financing activities	(129.7)	129.0	(48.4)
Effect of exchange rates on cash and cash equivalents	(0.5)	(1.2)	(0.4)
Net increase (decrease) in cash and cash equivalents	(80.2)	15.7	138.7
Cash and cash equivalents at beginning of period	236.3	220.6	81.9
Cash and cash equivalents at end of period	156.1	236.3	220.6
Supplemental disclosure of cash flow information:
Cash paid for interest	8.9	7.9	9.5
Income taxes paid (received), net of cash refunds	10.2	6.1	17.6
Supplemental disclosure of non-cash investing and financing activities:
Conversion of subordinated notes to common stock, net	0	0	16.7
Identified intangible assets and goodwill on acquisitions	5.6	1.8	4.9
Additional consideration payable related to acquisitions	$ 8.2	$ 2.1	$ 5.4