StoneX (SNEX) 10-K 14 Dec 16 2016 FY Annual report Financial data

DEI Document

DEI Document - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Dec. 12, 2016	Mar. 31, 2016
Document and Entity Information [Abstract]
Entity Registrant Name	INTL FCSTONE INC.
Trading Symbol	INTL
Entity Central Index Key	913,760
Current Fiscal Year End Date	--09-30
Entity Filer Category	Accelerated Filer
Document Type	10-K
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		18,468,751
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 400.8

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Statement of Financial Position [Abstract]
Cash and cash equivalents	$ 316.2	$ 268.1
Cash, securities and other assets segregated under federal and other regulations (including $618.8 and $515.5 at fair value at September 30, 2016 and September 30, 2015, respectively)	1,136.3	756.9
Securities purchased under agreements to resell	609.6	325.3
Deposits with and receivables from:
Exchange-clearing organizations (including $868.5 and $1,009.4 at fair value at September 30, 2016 and September 30, 2016, respectively)	1,524.4	1,533.5
Broker-dealers, clearing organizations and counterparties (including $(15.2) and $(52.9) at fair value at September 30, 2016 and September 30, 2015, respectively)	237	277.6
Receivables from customers, net	194.5	217.3
Notes receivable, net	18.9	78.4
Income taxes receivable	1.1	10.6
Financial instruments owned, at fair value (includes securities pledged as collateral that can be sold or repledged of $47.2 and $170.7 at September 30, 2016 and September 30, 2015, respectively)	1,606.1	1,421.9
Physical commodities inventory (including $71.2 and $15.2 at fair value at September 30, 2016 and September 30, 2015, respectively)	123.8	32.8
Deferred income taxes, net	34.5	28.2
Property and equipment, net	29.4	19.7
Goodwill and intangible assets, net	56.6	58.1
Other assets	62.9	41.6
Total assets	5,951.3	5,070
Liabilities:
Accounts payable and other accrued liabilities (including $0.8 and $3.3 at fair value at September 30, 2016 and September 30, 2015)	161.3	144.8
Payable to:
Customers	2,854.2	2,593.5
Broker-dealers, clearing organizations and counterparties (including $3.5 and $1.6 at fair value at September 30, 2016 and September 30, 2015, respectively)	260.1	262.9
Lenders under loans	182.8	41.6
Senior unsecured notes	45.5	45.5
Income taxes payable	7.1	9
Securities sold under agreements to repurchase	1,167.1	1,007.3
Financial instruments sold, not yet purchased, at fair value	839.4	568.3
Total liabilities	5,517.5	4,672.9
Commitments and contingencies (Note 11)
Stockholders’ equity:
Preferred stock, $0.01 par value. Authorized 1,000,000 shares; no shares issued or outstanding	0	0
Common stock, $0.01 par value. Authorized 30,000,000 shares; 20,557,175 issued and 18,435,218 outstanding at September 30, 2016 and 20,184,556 issued and 18,812,803 outstanding at September 30, 2015	0.2	0.2
Common stock in treasury, at cost - 2,121,957 shares at September 30, 2016 and 1,371,753 shares at September 30, 2015	(46.3)	(26.8)
Additional paid-in capital	249.4	240.8
Retained earnings	255.1	200.4
Accumulated other comprehensive loss, net	(24.6)	(17.5)
Total stockholders' equity	433.8	397.1
Total liabilities and stockholders' equity	$ 5,951.3	$ 5,070

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Assets [Abstract]
Securities and other assets segregated, fair value	$ 618.8	$ 515.5
Dep and rec -exch clear org - fair value	868.5	1,009.4
Dep and rec -b/d- fair value	(15.2)	(52.9)
Physical commodities inventory at fair value	71.2	15.2
Securities Sold under Agreements to Repurchase, Fair Value of Collateral	47.2	170.7
Accounts pay and other accrued - fair value	0.8	3.3
Payables to b/ds and counterparties at fair value	$ 3.5	$ 1.6
Preferred stock - par value	$ 0.01	$ 0.01
Preferred stock - authorized	1,000,000	1,000,000
Preferred stock - issued	0	0
Preferred stock - outstanding	0	0
Common stock - par value	$ 0.01	$ 0.01
Common stock - authorized	30,000,000	30,000,000
Common stock - issued	20,557,175	20,184,556
Common stock - outstanding	18,435,218	18,812,803
Treasury stock - shares	2,121,957	1,371,753

Consolidated Income Statements

Consolidated Income Statements - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Revenues:
Sales of physical commodities	$ 14,112	$ 34,089.9	$ 33,546.4
Trading gains, net	321.2	328.6	244.5
Commission and clearing fees	224.3	192.5	180.7
Consulting and management fees	42	42.5	42.1
Interest income	55.2	39.4	8
Other Income	0.2	0.3	0.7
Total revenues	14,754.9	34,693.2	34,022.4
Cost of sales of physical commodities	14,083.9	34,068.9	33,531.5
Operating revenues	671	624.3	490.9
Transaction-based clearing expenses	129.9	122.7	108.5
Introducing broker commissions	68.9	52.7	49.9
Interest expense	28.3	17.1	10.5
Net operating revenues	443.9	431.8	322
Compensation and other expenses:
Compensation and benefits	263.9	251.1	201.9
Communication and data services	32.7	28.1	25.8
Occupancy and equipment rental	13.3	13.5	12.3
Professional fees	14	12.5	14.9
Travel and business development	11.5	10.5	9.9
Depreciation and amortization	8.2	7.2	7.3
Bad debts and impairments	4.4	7.3	5.5
Other	29.4	23.5	18.4
Total compensation and other expenses	377.4	353.7	296
Gain on acquisition	6.2	0	0
Income from continuing operations, before tax	72.7	78.1	26
Income tax expense	18	22.4	6.4
Net income from continuing operations	54.7	55.7	19.6
Loss from discontinued operations, net of tax	0	0	(0.3)
Net income	$ 54.7	$ 55.7	$ 19.3
Basic earnings per share:
Income from continuing operations	$ 2.94	$ 2.94	$ 1.03
Loss from discontinued operations	0	0	(0.02)
Net income per common share	2.94	2.94	1.01
Diluted earnings per share:
Income from continuing operations	2.90	2.87	1
Loss income from discontinued operations	0	0	(0.02)
Net income per common share	$ 2.90	$ 2.87	$ 0.98
Weighted-average number of common shares outstanding:
Basic	18,410,561	18,525,374	18,528,302
Diluted	18,625,372	18,932,235	19,132,302

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income Statement - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 54.7	$ 55.7	$ 19.3
Other comprehensive income (loss), net of tax [Abstract]
Foreign currency translation adjustment	(7.4)	(4)	(4.6)
Pension liabilities adjustment	(0.2)	(1.5)	(0.8)
Net unrealized gain on available-for-sale securities	0	2.7	0.2
Reclassification of adjustment for gains included in net income:
Periodic pension costs (included in compensation and benefits)	0.5	0.3	0.2
Realized gain on available-for-sale securities (included in trading gains, net and interest income)	0	(5.4)	(0.1)
Income tax expense from reclassification adjustments (included in income tax expense)	0	2	(0.1)
Reclassification adjustment for gains included in net income	0.5	(3.1)	0
Other comprehensive loss	(7.1)	(5.9)	(5.2)
Comprehensive income	$ 47.6	$ 49.8	$ 14.1

Consolidated Cash Flows Stateme

Consolidated Cash Flows Statements - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities:
Net income	$ 54.7	$ 55.7	$ 19.3
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	7.8	7.2	7.3
Provision for bad debts and impairments	4.4	7.3	5.5
Deferred income taxes	(0.8)	4.8	(6.8)
Amortization of debt issuance costs and debt discount	1.1	0.9	1
Amortization of share-based compensation expense	5.1	3.6	4.3
Loss on sale of property and equipment	0.4	0.5	0.3
Gain on acquisition	(6.2)	0	0
Gain on sale of exchange memberships and common stock	0	(1.2)	0
Changes in operating assets and liabilities, net:
Cash, securities and other assets segregated under federal and other regulations	(379.9)	(315)	(1.3)
Change in securities purchased under agreements to resell	(285.1)	15.2	0
Deposits and receivables from exchange-clearing organizations	10.9	195.1	(159.2)
Deposits and receivables from broker-dealers, clearing organizations, and counterparties	135.7	(150.2)	1.1
Receivable from customers, net	97.8	(169)	32
Notes receivable, net	59.5	(14.5)	(27.9)
Income taxes receivable	8.2	0	4.2
Financial instruments owned, at fair value	(192.9)	(565)	(42.6)
Physical commodities inventory	(91)	7.1	17.8
Other assets	(17.4)	(16.2)	0.1
Accounts payable and other accrued liabilities	7.5	23.2	1.9
Payable to customers	172.2	332.1	191.5
Payable to broker-dealers, clearing organizations and counterparties	(53.8)	251.1	(5.2)
Income taxes payable	0.3	1.7	5.2
Securities sold under agreements to repurchase	159.8	186	0
Financial instruments sold, not yet purchased, at fair value	273.9	177.5	84.1
Net cash (used in) provided by operating activities	(27.8)	37.9	132.6
Cash flows from investing activities:
Cash paid for acquisitions, net	(20)	(7.8)	0
Purchase of exchange memberships and common stock	(0.1)	(0.7)	0
Sale of exchange memberships and common stock	0	2.1	0
Purchase of property and equipment	(15.4)	(9.1)	(4.3)
Net cash used in investing activities	(35.5)	(15.5)	(4.3)
Cash flows from financing activities:
Net change in payable to lenders under loans	142	15.5	(38.5)
Payments related to earn-outs on acquisitions	(2.9)	(2.2)	(1.6)
Proceeds from notes payable	0	4	0
Repayment of note payable	0.8	0.4	0
Share repurchase	(19.5)	(4.7)	(9.7)
Debt issuance costs	(2.1)	(0.2)	(0.3)
Exercise of stock options	3.5	2.5	1.4
Income tax benefit on stock options and awards	0.8	0.5	(0.1)
Net cash provided by (used in) financing activities	121	15	(48.8)
Effect of exchange rates on cash and cash equivalents	(9.6)	(0.6)	(4.3)
Net increase in cash and cash equivalents	48.1	36.8	75.2
Cash and cash equivalents at beginning of period	268.1	231.3	156.1
Cash and cash equivalents at end of period	316.2	268.1	231.3
Supplemental disclosure of cash flow information:
Cash paid for interest	26	15.8	9.6
Income taxes paid, net of cash refunds	8.5	15.3	3
Supplemental disclosure of non-cash investing and financing activities:
Identified intangible assets and goodwill on acquisitions	0	1.6	0.5
Additional consideration payable related to acquisitions	(0.4)	1.9	(1.8)
Acquisition of business:
Assets acquired	187.1	1,011.4	0
Liabilities acquired	(136)	(995.1)	0
Total net assets acquired	51.1	16.3	0
Deferred consideration payable related to acquisitions	0	5	0
Escrow deposits related to acquisitions	$ 3.4	$ 5	$ 0

Consolidated Statements of Shar

Consolidated Statements of Shareholders’ Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]
Balances at beginning of period at Sep. 30, 2013	$ 335.4	$ 0.2	$ (7.8)	$ 224	$ 125.4	$ (6.4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	19.3				19.3
Other comprehensive loss	(5.2)					(5.2)
Excercise of stock options	1.3			1.3
Share-based compensation	4.3			4.3
Repurchase of stock	(9.7)		(9.7)
Repurchase of stock - adjustments to APIC				0
Balances at end of period at Sep. 30, 2014	345.4	0.2	(17.5)	229.6	144.7	(11.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	55.7				55.7
Other comprehensive loss	(5.9)					(5.9)
Excercise of stock options	3			3
Share-based compensation	3.6			3.6
Repurchase of stock	(4.7)		(4.5)
Stock held in escrow for business combination - share recapture			(4.8)
Repurchase of stock - adjustments to APIC				(0.2)
Stock held in escrow for business combination	0			4.8
Balances at end of period at Sep. 30, 2015	397.1	0.2	(26.8)	240.8	200.4	(17.5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	54.7				54.7
Other comprehensive loss	(7.1)					(7.1)
Excercise of stock options	3.5			3.5
Share-based compensation	5.1			5.1
Repurchase of stock	(19.5)		(19.5)
Stock held in escrow for business combination				0
Balances at end of period at Sep. 30, 2016	$ 433.8	$ 0.2	$ (46.3)	$ 249.4	$ 255.1	$ (24.6)

Description of Business and Sig

Description of Business and Significant Accounting Policies (Notes)	12 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Business Description and Accounting Policies [Text Block]	Description of Business and Significant Accounting Policies INTL FCStone Inc. , a Delaware corporation, and its consolidated subsidiaries (collectively “INTL” or “the Company”), is a diversified global financial services organization providing execution, risk management and advisory services, market intelligence, and clearing services across assets classes and markets around the world. The Company’s services include comprehensive risk management advisory services for commercial customers; execution of listed futures and options on futures contracts on all major commodity exchanges; structured over-the-counter (“OTC”) products in a wide range of commodities; physical trading and hedging of precious and base metals and select other commodities; trading of more than 140 foreign currencies; market-making in international equities; fixed income; debt origination and asset management. The Company provides these services to a diverse group of more than 20,000 predominantly wholesale organizations located throughout the world, including producers, processors and end-users of nearly all widely-traded physical commodities to manage their risks and enhance margins; to commercial counterparties who are end-users of the firm’s products and services; to governmental and non-governmental organizations; and to commercial banks, brokers, institutional investors and major investment banks. Basis of Presentation The accompanying consolidated financial statements include the accounts of INTL FCStone Inc. and all other entities in which the Company has a controlling financial interest. All material intercompany transactions and balances have been eliminated in consolidation. Unless otherwise stated herein, all references to fiscal 2016 , fiscal 2015 , and fiscal 2014 refer to the Company’s fiscal years ended September 30. In the consolidated income statements, the total revenues reported combine gross revenues for the physical commodities business and net revenues for all other businesses. The subtotal ‘operating revenues’ in the consolidated income statements is calculated by deducting physical commodities cost of sales from total revenues. The subtotal ‘net operating revenues’ in the consolidated income statements is calculated as operating revenues less transaction based clearing expenses, introducing broker commissions and interest expense. Transaction-based clearing expenses represent variable expenses paid to executing brokers, exchanges, clearing organizations and banks in relation to our transactional volumes. Introducing broker commissions include commission paid to non-employee third parties that have introduced customers to the Company. Net operating revenues represent revenues available to pay variable compensation to risk management consultants and traders and direct non-variable expenses, as well as variable and non-variable expenses of operational and administrative employees. Use of Estimates The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent liabilities as of the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. The most significant of these estimates and assumptions relate to fair value measurements for financial instruments and investments, revenue recognition, the provision for potential losses from bad debts, valuation of inventories, valuation of goodwill and intangible assets, self-insurance liabilities, incomes taxes and contingencies. These estimates are based on management’s best knowledge of current events and actions the Company may undertake in the future. The Company reviews all significant estimates affecting the financial statements on a recurring basis and records the effect of any necessary adjustments prior to their issuance. Although these and other estimates and assumptions are based on the best available information, actual results could be materially different from these estimates. Internal Subsidiary Consolidation Effective July 1, 2015, the Company merged three of its wholly-owned regulated United States (“U.S.”) subsidiaries into its wholly owned regulated U.S. subsidiary, INTL FCStone Securities Inc., and the surviving entity was renamed INTL FCStone Financial Inc. (“INTL FCStone Financial”) and is registered as both a broker-dealer and a futures commission merchant (“FCM”). As such, the assets, liabilities and equity of FCStone, LLC, INTL FCStone Partners L.P., and FCC Investments, Inc. were transferred into INTL FCStone Financial. Foreign Currency Translation Assets and liabilities recorded in foreign currencies are translated at the exchange rates prevailing on the balance sheet date. Revenue and expenses are translated at average rates of exchange prevailing during the period. Gains or losses on translation of the financial statements of a non-U.S. operation, when the functional currency is other than the U.S. dollar, are recorded in other comprehensive income (“OCI”), net of tax, a component of stockholders’ equity. Foreign currency remeasurement gains or losses on transactions denominated in nonfunctional currencies are included in ‘trading gains, net’ in the consolidated income statements. Cash and Cash Equivalents The Company considers cash held at banks and all highly liquid investments, including certificates of deposit, which may be withdrawn at any time at the discretion of the Company without penalty, to be cash and cash equivalents. Cash and cash equivalents consist of cash, foreign currency, money market funds and certificates of deposit not deposited with or pledged to exchange-clearing organizations, broker-dealers, clearing organizations or counterparties. The money market funds are valued at period-end at the net asset value provided by the fund’s administrator, which approximates fair value. Certificates of deposit are stated at cost plus accrued interest, which approximates fair value. The Company has an investment policy, which limits the maximum amount placed in any one fund and with any one institution in order to reduce credit risk. The Company does not believe that it is exposed to significant risk on cash and cash equivalents. Cash, Securities and Other Assets Segregated under Federal and other Regulations Pursuant to requirements of the Commodity Exchange Act in the U.S. and similarly in the United Kingdom (“U.K.”), pursuant to the Markets in Financial Instruments Implementing Directive 2006/73/EC underpinning the Client Asset or ‘CASS’ rules in the Financial Services Authority (“FSA”) handbook, funds deposited by customers relating to futures and options on futures contracts in regulated commodities must be carried in separate accounts which are designated as segregated customer accounts. The deposits in segregated customer accounts are not commingled with the funds of the Company. Under the FSA’s rules, certain categories of customers may choose to opt-out of segregation. As of September 30, 2016 and 2015 , cash, securities and other assets segregated under federal and other regulations consisted of cash held at banks and money market funds of approximately $515.2 million and $240.0 million , respectively, U.S. government securities and U.S. government agency obligations of approximately $595.5 million and $493.4 million , respectively, and commodities warehouse receipts of approximately $23.3 million and $22.1 million , respectively (see fair value measurements discussion in Note 3 ). Deposits and Receivables from Exchange-Clearing Organizations, Broker-dealers, Clearing Organizations and Counterparties, and Payables to Broker-dealers, Clearing Organizations and Counterparties As required by the regulations of the U.S. Commodity Futures Trading Commission (“CFTC”) and the aforementioned FSA handbook, customer funds received to margin, guarantee, and/or secure commodity futures transactions are segregated and accounted for separately from the general assets of the Company. Deposits with exchange-clearing organizations, broker-dealers and counterparties pertain primarily to deposits made to satisfy margin requirements on customer and proprietary open futures and options on futures positions and to satisfy the requirements set by clearing exchanges for clearing membership. The Company also pledges margin deposit with various counterparties for OTC derivative contracts, and these deposits are also included in deposits and receivables from broker-dealers and counterparties. Deposits with and receivables from exchange-clearing organizations and broker-dealers and counterparties are reported gross, except where a right of offset exists. As of September 30, 2016 and 2015 , the Company had cash and cash equivalents on deposit with or pledged to exchange-clearing organizations, broker-dealers and counterparties of $0.9 billion . These balances also include securities pledged by the Company on behalf of customers and customer-owned securities that are pledged. It is the Company’s practice to include customer owned securities on its consolidated balance sheets, as the rights to those securities have been transferred to the Company under the terms of the futures trading agreement. Securities pledged include U.S. Treasury bills and instruments backed by U.S. government sponsored entities and government-sponsored enterprise backed mortgage-backed securities (“mortgage-backed securities”). Securities that are not customer-owned are adjusted to fair value with associated changes in unrealized gains or losses recorded through current period earnings. For customer owned securities, the change in fair value is offset against the payable to customers with no impact recognized in the consolidated income statements. The securities, primarily U.S. government obligations and mortgage-backed securities, held by INTL FCStone Financial, a subsidiary of the Company, as collateral or as margin have been deposited with exchange-clearing organizations, broker-dealers or other counterparties. The fair value of these securities was approximately $0.5 billion as of September 30, 2016 and 2015 . Management has considered guidance required by the Transfers and Servicing Topic of the ASC as it relates to securities pledged by customers to margin their accounts within the FCM Division of INTL FCStone Financial. Based on a review of the agreements with the customer, management believes the transferor surrenders control over those assets because: (a) the transferred assets have been isolated from the transferor—put presumptively beyond the reach of the transferor and its creditors, even in bankruptcy or other receivership, (b) each transferee has the right to pledge or exchange the assets (or beneficial interests) it received, and no condition both constrains the transferee (or holder) from taking advantage of its right to pledge or exchange and provides more than a trivial benefit to the transferor and (c) the transferor does not maintain effective control over the transferred assets through either (1) an agreement that both entitles and obligates the transferor to repurchase or redeem them before their maturity or (2) the ability to unilaterally cause the holder to return specific assets, other than through a cleanup call. Under this guidance, the Company reflects the customer collateral assets and corresponding liabilities in the Company’s consolidated balance sheets as of September 30, 2016 and 2015 . In addition to margin, deposits with exchange-clearing organizations include guaranty deposits. The guaranty deposits are held by the clearing organization for use in potential default situations by one or more members of the clearing organization. The guaranty deposits may be applied to the Company’s obligations to the clearing organization, or to the clearing organization’s obligations to other clearing members or third parties. The Company maintains customer omnibus and proprietary accounts with other counterparties, and the equity balances in those accounts along with any margin cash or securities deposited with the carrying broker are included in deposits and receivables from broker-dealers and counterparties. Receivables from and payables to exchange-clearing organizations are also comprised of amounts due from or due to exchange-clearing organizations for daily variation settlements on open futures and options on futures positions. The variation settlements due from or due to exchange-clearing organizations are paid in cash on the following business day. Deposits and receivables from broker-dealers, clearing organizations and counterparties, and payables to broker-dealers, clearing organizations and counterparties also include amounts related to the value of customers cross-currency payment transactions related to the Global Payments segment. These amounts arise due to a clearing period before the funds are received and payments are made, which usually is one to two business days. Deposits and receivables with exchange-clearing organizations also includes the unrealized gains and losses associated with the customers’ options on futures contracts. See discussion in the Financial Instruments and Derivatives section below for additional information on the treatment of derivative contracts. For customer owned derivative contracts, the fair value is offset against the payable to customers with no impact recognized on the consolidated income statements. Receivable from and Payable to Customers Receivable from customers, net of the allowance for doubtful accounts, include the total of net deficits in individual exchange-traded and OTC trading accounts carried by the Company. Customer deficits arise from realized and unrealized trading losses on futures, options on futures, swaps and forwards and amounts due on cash and margin transactions. Customer deficit accounts are reported gross of customer accounts that contain net credit or positive balances, except where a right of offset exists. Net deficits in individual exchange-traded and OTC trading accounts include both secured and unsecured deficit balances due from customers as of the balance sheet date. Secured deficit amounts are backed by U.S. Treasury bills and notes and commodity warehouse receipts. These U.S Treasury bills and notes and commodity warehouse receipts are not netted against the secured deficit amounts, as the conditions for right of setoff have not been met. Payable to customers represent the total of customer accounts with credit or positive balances. Customer accounts are used primarily in connection with commodity transactions and include gains and losses on open commodity trades as well as securities and other deposits made as required by the Company, the exchange-clearing organizations or other clearing organizations. Customer accounts with credit or positive balances are reported gross of customer deficit accounts, except where a right of offset exists. Receivables from and payables to customers also include amounts related to the value of customers cross-currency payment transactions related to the Global Payments segment. These amounts arise due to a clearing period before the funds are received and payments are made, which usually is one to two business days. The future collectability of the receivable from customers can be impacted by the Company’s collection efforts, the financial stability of its customers, and the general economic climate in which it operates. The Company evaluates accounts that it believes may become uncollectible on a specific identification basis, through reviewing daily margin deficit reports, the historical daily aging of the receivables, and by monitoring the financial strength of its customers. The Company may unilaterally close customer trading positions in certain circumstances. In addition, to evaluate customer margining and collateral requirements, customer positions are stress tested regularly and monitored for excessive concentration levels relative to the overall market size. The Company generally charges off an outstanding receivable balance when all economically sensible means of recovery have been exhausted. That determination considers information such as the occurrence of significant changes in the customer’s financial position such that the customer can no longer pay the obligation, or that the proceeds from collateral will not be sufficient to pay the balance. Notes Receivable The Company originates short-term notes receivable from customers with the outstanding balances typically being insured 90% to 98% by a third party, including accrued interest, subject to applicable deductible amounts. The Company may sell the insured portion of the notes through non-recourse participation agreements with other third parties. See discussion of notes receivable related to commodity repurchase agreements below. Accrual of commodity financing income on any note is discontinued when, in the opinion of management, there is reasonable doubt as to the timely collectability of interest or principal. Nonaccrual notes are returned to an accrual status when, in the opinion of management, the financial position of the borrower indicates there is no longer any reasonable doubt as to the timely payment of principal and interest. The Company records a charge against earnings for notes receivable losses when management believes that collectability of the principal is unlikely. Physical Commodities Inventory Inventories of certain agricultural commodities are carried at net realizable value, which approximates fair value less disposal costs. The agricultural commodities inventories have reliable, readily determinable and realizable market prices, have relatively predictable and insignificant costs of disposal and are available for immediate delivery. Changes in the fair values of these agricultural commodities inventories are included as a component of ‘cost of physical commodities sold’ in the consolidated income statements. Inventories of precious metals, except as described below, are stated at the lower of cost or market (“LCM”), using the weighted-average price and first-in first-out costing method. Prior to the transfer of the Company’s precious metals business (see following discussion), precious metals inventory held by INTL Commodities Inc. was valued at LCM under the provisions of the Inventory Topic of the Accounting Standards Codification (“ASC”), using the weighted-average price and first-in first-out costing method. Subsequent to the transfer, precious metals inventory held by INTL FCStone Ltd is measured at fair value, with changes in fair value included as a component of ‘trading gains, net’ in the consolidated income statements. Change in Precious Metals Accounting The Company engages in trading activities in a variety of physical commodities, including actively trading precious metals whereby the Company provides a full range of trading and hedging capabilities, including OTC products, to select producers, consumers, and investors. In the Company’s precious metals trading activities, it acts as a principal, committing its own capital to buy and sell precious metals on a spot and forward basis. On April 10, 2015 (the “transfer date”), the Company transitioned the portion of its precious metals business conducted through its unregulated domestic subsidiary, INTL Commodities Inc., to its United Kingdom based broker-dealer subsidiary, INTL FCStone Ltd INTL FCStone Ltd is regulated by the Financial Conduct Authority (“FCA”), the regulator of the financial services industry in the United Kingdom. In anticipation of the transfer of the precious metals business, INTL Commodities Inc. liquidated all of its precious metals inventory as of the transfer date. Subsequent to the transfer, precious metals inventory held by INTL FCStone Ltd is measured at fair value, with changes in fair value included as a component of ‘trading gains, net’ in the consolidated income statement, in accordance with U.S. GAAP accounting requirements for broker-dealers. Precious metals inventory held by subsidiaries that are not broker-dealers continues to be valued at the lower of cost or market value. Property and Equipment Property and equipment is stated at cost, net of accumulated depreciation and amortization and depreciated using the straight-line method over the estimated useful lives of the assets. Leasehold improvements are amortized on a straight-line basis over the estimated useful life of the improvement or the term of the lease, whichever is shorter. Certain costs of software developed or obtained for internal use are capitalized and amortized over the estimated useful life of the software. Expenditures for maintenance, repairs, and minor replacements are charged against earnings, as incurred. Expenditures that increase the value or productive capacity of assets are capitalized. When property and equipment are retired, sold, or otherwise disposed of, the asset’s carrying amount and related accumulated depreciation are removed from the accounts and any gain or loss is included in earnings. Goodwill and Identifiable Intangible Assets Goodwill is the cost of acquired companies in excess of the fair value of identifiable net assets at acquisition date. In accordance with the Intangibles – Goodwill and Other Topic of the ASC, goodwill is tested for impairment on an annual basis at the fiscal year-end, and between annual tests if indicators of potential impairment exist, using a fair-value-based approach. No impairment of goodwill has been identified during any of the periods presented. Identifiable intangible assets subject to amortization are amortized using the straight-line method over their estimated period of benefit, ranging from two to twenty years. Identifiable intangible assets are tested for impairment whenever events or changes in circumstances suggest that an asset’s or asset group’s carrying value may not be fully recoverable in accordance with the Intangibles – Goodwill and Other Topic of the ASC. Residual value is presumed to be zero. Identifiable intangible assets not subject to amortization are reviewed at each reporting period to re-evaluate if the intangible asset’s useful life remains indefinite. Additionally, intangible assets not subject to amortization are tested annually for impairment at the fiscal year-end, and between annual tests if indicators of potential impairment exist, using a fair-value-based approach. Financial Instruments and Derivatives Financial instruments owned and sold, not yet purchased, at fair value consist of financial instruments carried at fair value or amounts that approximate fair value, with related unrealized changes in gains or losses recognized in earnings. The fair value of a financial instrument is the amount at which the instrument could be exchanged in a current transaction between willing parties, other than in a forced or liquidation sale. The Company accounts for its securities pledged on behalf of customers and proprietary securities as trading securities in accordance with U.S. GAAP accounting requirements for broker-dealers. Investment in managed funds, at fair value represents investments in funds managed by the Company’s fund managers. The investments are valued at period-end at the net asset value provided by the fund’s administrator. Commodities warehouse receipts are valued at the cash price, or the nearby futures prices in the absence of a cash price, for the commodity based on published market quotes. For commodities warehouse receipts, the change in fair value is offset against the payable to customers with no impact on the consolidated income statements. The Company utilizes derivative instruments to manage exposures to foreign currency, commodity price and interest rate risks for the Company and its customers. The Company’s objectives for holding derivatives include reducing, eliminating, and efficiently managing the economic impact of these exposures as effectively as possible. Derivative instruments are recognized as either assets or liabilities and are measured at fair value. The accounting for changes in the fair value of a derivative depends on the intended use of the derivative and the resulting designation. For a derivative instrument designated as a cash flow hedge, the effective portion of the derivative’s gain or loss is initially recorded in OCI, net of tax, and is subsequently recognized in earnings when the hedged exposure affects earnings. The ineffective portion of the gain or loss is recognized in earnings. Gains and losses from changes in fair values of derivatives that are not designated as cash flow hedges for accounting purposes are recognized in earnings. The Company’s derivative contracts consist of exchange-traded and OTC derivatives. Fair values of exchange-traded derivatives are generally determined from quoted market prices. OTC derivatives are valued using valuation models. The valuation models used to derive the fair values of OTC derivatives require inputs including contractual terms, market prices, yield curves and measurements of volatility. The Company uses similar models to value similar instruments. Where possible, the Company verifies the values produced by pricing models by comparing them to market transactions. Inputs may involve judgment where market prices are not readily available. The Company does not elect hedge accounting under the Derivatives and Hedging Topic of the ASC in accounting for derivatives used as economic hedges on its commodities. The Company’s derivative contracts also include forward purchase and sale contracts for physical delivery of the agricultural commodities in a future period. Contracts to purchase agricultural commodities generally relate to the current or future crop year. Contracts for the sale of agricultural commodities generally do not extend beyond one year. Forward purchase and sale contracts are valued at market prices when available or other market quotes adjusted for differences, primarily in transportation, between the exchange-traded market and local markets where the terms of the contracts are based. Changes in the fair value of agricultural commodity inventories held for sale, forward purchase and sale contracts and exchange-traded futures and options contracts are recognized as a component of cost of sales of physical commodities. The Company provides clearing and execution of exchange-traded futures and options on futures for middle-market intermediaries, end-users, producers of commodities and the institutional and professional trader market segments. The Company has a subsidiary that is a registered broker-dealer/FCM, clearing on various exchanges. A primary source of revenues for the Company’s broker-dealer/FCM are commissions and clearing fees derived from executing and clearing orders for commodity futures contracts and options on futures on behalf of its customers. The Company also brokers foreign exchange forwards, options and cash, or spot, transactions between customers and external counterparties. A portion of the contracts are arranged on an offsetting basis, limiting the Company’s risk to performance of the two offsetting parties. The offsetting nature of the contracts eliminates the effects of market fluctuations on the Company’s operating results. Due to the Company’s role as a principal participating in both sides of these contracts, the amounts are presented gross on the consolidated balance sheets at their respective fair values, net of offsetting assets and liabilities. The Company holds proprietary positions in its foreign exchange line of business. On a limited basis, the Company’s foreign exchange trade desk will accept a customer transaction and will offset that transaction with a similar but not identical position with a counterparty. These unmatched transactions are intended to be short-term in nature and are often conducted to facilitate the most effective transaction for the Company’s customer. These spot and forward contracts are accounted for as free-standing derivatives and reported in the consolidated balance sheets at their fair values. The Company does not seek hedge accounting treatment for these derivatives, and accordingly, the changes in fair value during the period are recorded in the consolidated income statements in ‘trading gains, net’ (see Note 4 ). In applying the guidance in the Balance Sheet-Offsetting Topic of the ASC, the Company’s accounting policy is such that open contracts with the same customer are netted at the account level, in accordance with netting arrangements in place with each party, as applicable and rights to reclaim cash collateral or obligations to return cash collateral are netted against fair value amounts recognized for derivative instruments with the same customer in accordance with the master netting arrangements in place with each customer. The Company may lease commodities to or from customers or counterparties, or advance commodities to customers on an unpriced basis, receiving payment when they become priced. These are valued at fair value utilizing the fair value option based on guidance in the Financial Instruments Topic of the ASC. As permitted by the fair value option election, the entire instrument is recorded at fair value in the consolidated balance sheets as a component of ‘financial instruments owned and sold, not yet purchased’. Due to the short term nature of the instruments, the balance of the agreements is not materially different than the recorded fair value. The corresponding change in fair value of the instrument is recognized in the consolidated income statements as a component of ‘trading gains, net’ for the fiscal years ended September 30, 2016, 2015, and 2014 . The Company does elect to value all of their commodities lease agreements at fair value using the fair value option. See fair value measurements in Note 3 . Exchange Memberships and Stock The Company is required to hold certain exchange membership seats and exchange firm common stock and pledge them for clearing purposes, in order to provide the Company the right to process trades directly with the various exchanges. Exchange memberships include seats on the Chicago Board of Trade (“CBOT”), the Minneapolis Grain Exchange, the New York Mercantile Exchange (“NYMEX”), the Commodity Exchange, Inc. (“COMEX”) Division of the New York Mercantile Exchange, Mercado de Valores de Buenos Aires S.A. (“MERVAL”), the Chicago Mercantile Exchange (“CME”) Growth and Emerging Markets, InterContinental Exchange, Inc. (“ICE”) Futures US, ICE Europe Ltd and London Metal Exchange (“LME”), and the Deposit Trust and Clearing Corporation (“DTCC”). Exchange firm common stock include shares of CME Group, Inc., ICE and LME. Exchange memberships and firm common stocks pledged for clearing purposes are recorded at cost and are included in ‘other assets’ on the consolidated balance sheets. Equity investments in exchange firm common stock not pledged for clearing purposes are classified as trading securities and recorded at fair value, with unrealized gains and losses recorded as a component of “trading gains, net” on the consolidated income statements. Equity investments in exchange firm common stock not pledged for clearing purposes are included in ‘financial instruments owned’ on the consolidated balance sheets. The cost basis for exchange memberships and firm common stock pledged for clearing purposes was $12.1 million and $9.9 million as of September 30, 2016 and 2015 , respectively. The fair value of exchange memberships and firm common stock pledged for clearing purposes was $9.1 million and $7.6 million as of September 30, 2016 and 2015 , respectively. The fair value of exchange firm common stock is determined by quoted market prices, and the fair value of exchange memberships is determined by recent sale transactions. The Company monitors the fair value of exchange membership seats and firm common stock on a quarterly basis, and does not consider any current unrealized losses on individual exchange memberships to be anything other than a temporary impairment. Commodity and Other Repurchase Agreements and Collateralized Transactions In the normal course of operations the Company executes notes receivable under sale/repurchase agreements with customers whereby the customers sell certain commodity inventory or other investments and agree to repurchase the commodity inventory or investment at a future date at a fixed rate. These transactions are short-term in

Earnings per Share (Notes)

Earnings per Share (Notes)	12 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Earnings Per Share [Text Block]	Earnings per Share The Company presents basic and diluted earnings per share (“EPS”) using the two-class method which requires all outstanding unvested share-based payment awards that contain rights to non-forfeitable dividends and therefore participate in undistributed earnings with common stockholders be included in computing earnings per share. Under the two-class method, net earnings are reduced by the amount of dividends declared in the period for each class of common stock and participating security. The remaining undistributed earnings are then allocated to common stock and participating securities, based on their respective rights to receive dividends. Restricted stock awards granted to certain employees and directors contain non-forfeitable rights to dividends at the same rate as common stock, and are considered participating securities. Basic EPS has been computed by dividing net income by the weighted-average number of common shares outstanding. The following is a reconciliation of the numerator and denominator of the diluted net income per share computations for the periods presented below. Year Ended September 30, (in millions, except share amounts) 2016 2015 2014 Numerator: Income from continuing operations $ 54.7 $ 55.7 $ 19.6 Less: Allocation to participating securities (1.0 ) (1.3 ) (0.5 ) Income from continuing operations allocated to common stockholders $ 53.7 $ 54.4 $ 19.1 Loss from discontinued operations $ — $ — $ (0.3 ) Less: Allocation to participating securities — — — Loss from discontinued operations allocated to common stockholders $ — $ — $ (0.3 ) Diluted net income $ 54.7 $ 55.7 $ 19.3 Less: Allocation to participating securities (1.0 ) (1.3 ) (0.5 ) Diluted net income allocated to common stockholders $ 53.7 $ 54.4 $ 18.8 Denominator: Weighted average number of: Common shares outstanding 18,410,561 18,525,374 18,528,302 Dilutive potential common shares outstanding: Share-based awards 214,811 406,861 604,000 Diluted shares outstanding 18,625,372 18,932,235 19,132,302 The dilutive effect of share-based awards is reflected in diluted net income per share by application of the treasury stock method, which includes consideration of unamortized share-based compensation expense required under the Compensation – Stock Compensation Topic of the ASC. Options to purchase 910,060 , 997,459 and 1,120,985 shares of common stock for fiscal years ended September 30, 2016, 2015, and 2014 , respectively, were excluded from the calculation of diluted earnings per share because they would have been anti-dilutive.

Assets and Liabilities, at Fair

Assets and Liabilities, at Fair Value (Notes)	12 Months Ended
	Sep. 30, 2016
Assets and Liabilities, at Fair Value [Abstract]
Fair Value Disclosures [Text Block]	Assets and Liabilities, at Fair Value The Company’s financial and nonfinancial assets and liabilities reported at fair value are included in the following captions on the consolidated balance sheets: • Cash and cash equivalents • Cash, securities and other assets segregated under federal and other regulations • Deposits and receivables from exchange-clearing organizations, broker-dealers, clearing organizations and counterparties • Financial instruments owned and sold, not yet purchased • Physical commodities inventory • Accounts payable and other accrued liabilities • Payable to broker-dealers, clearing organizations and counterparties Fair Value Hierarchy As required by the Fair Value Measurement Topic of the ASC, financial and nonfinancial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). A market is active if there are sufficient transactions on an ongoing basis to provide current pricing information for the asset or liability, pricing information is released publicly, and price quotations do not vary substantially either over time or among market makers. Observable inputs reflect the assumptions market participants would use in pricing the asset or liability developed based on market data obtained from sources independent of the reporting entity. The guidance requires the Company to consider counterparty credit risk of all parties to outstanding derivative instruments that would be considered by a market participant in the transfer or settlement of such contracts (exit price). The Company’s exposure to credit risk on derivative financial instruments relates to the portfolio of OTC derivative contracts as all exchange-traded contracts held can be settled on an active market with the credit guarantee by the respective exchange. The Company requires each counterparty to deposit margin collateral for all OTC instruments and is also required to deposit margin collateral with counterparties. The Company has assessed the nature of these deposits and used its discretion to adjust each based on the underlying credit considerations for the counterparty and determined that the collateral deposits minimize the exposure to counterparty credit risk in the evaluation of the fair value of OTC instruments as determined by a market participant. The majority of financial assets and liabilities on the consolidated balance sheets are reported at fair value. Cash is reported at the balance held at financial institutions. Cash equivalents includes money market funds, which are valued at period-end at the net asset value provided by the fund’s administrator, and certificates of deposit, which are stated at cost plus accrued interest, which approximates fair value. Cash, securities and other assets segregated under federal and other regulations include the value of cash collateral as well as the value of other pledged investments, primarily U.S. Treasury bills and obligations issued by government sponsored entities and commodities warehouse receipts. Deposits with and receivables from exchange-clearing organizations and broker-dealers, clearing organizations and counterparties and payable to customers and broker-dealers, clearing organizations and counterparties include the value of cash collateral as well as the value of money market funds and other pledged investments, primarily U.S. Treasury bills and obligations issued by government sponsored entities and mortgage-backed securities. These balances also include the fair value of exchange-traded futures and options on futures and exchange-cleared swaps and options determined by prices on the applicable exchange. Financial instruments owned and sold, not yet purchased include the value of U.S. and foreign government obligations, corporate debt securities, derivative financial instruments, commodities, mutual funds and investments in managed funds. The fair value of exchange common stock is determined by quoted market prices, and the fair value of exchange memberships is determined by recent sale transactions. Physical commodities inventory includes precious metals that are a part of the trading activities of a regulated broker-dealer subsidiary and is recorded at fair value using spot prices. Physical commodities inventory also includes agricultural and energy commodities that are a part of the trading activities of a non-broker dealer subsidiary and are also recorded at fair value using spot prices. The carrying value of receivables from customers, net and notes receivable, net approximates fair value, given their short duration. Payables to lenders under loans carry variable rates of interest and thus approximate fair value. The fair value of the Company’s senior unsecured notes was estimated to be $46.2 million and $46.6 million (carrying value of $45.5 million ) as of September 30, 2016 and 2015, respectively, based on the transaction prices at public exchanges for the same or similar issues. In the Rates Division of INTL FCStone Financial, the Company has amounts receivable from and payable to broker-dealers, clearing organizations and counterparties in connection with U.S. Treasury obligations, U.S. government agency obligations, and agency mortgage-backed and asset-backed obligations. Receivables from broker-dealers, clearing organizations and counterparties primarily include amounts receivable for securities sold but not yet delivered by the Company on settlement date (“fails-to-deliver”) and net receivables arising from unsettled trades. Payables to broker-dealers, clearing organizations and counterparties primarily include amounts payable for securities purchased, but not yet received by the Company on settlement date (“fails-to-receive”), net payables arising from unsettled trades. Due to their short-term nature, receivables from and payables to broker-dealers, clearing organizations and counterparties approximate fair value. In the Rates Division of INTL FCStone Financial, the Company has a significant amount of trading assets and liabilities. The Rates Division’s trading activities consists primarily of securities trading in connection with U.S. Treasury obligations, U.S. government agency obligations, and agency mortgage-backed and asset-backed obligations. The acquired assets and liabilities, including derivatives, are recorded on a trade date basis at fair value. The fair value estimates presented herein are based on pertinent information available to management as of September 30, 2016 and 2015 . Although management is not aware of any factors that would significantly affect the estimated fair value amounts, such amounts have not been comprehensively revalued for purposes of these financial statements since that date and current estimates of fair value may differ significantly from the amounts presented herein. Cash equivalents, securities, commodities warehouse receipts, derivative financial instruments and contingent liabilities are carried at fair value, on a recurring basis, and are classified and disclosed into three levels in the fair value hierarchy. The Company did not have any fair value adjustments for assets or liabilities measured at fair value on a non-recurring basis during the years ended September 30, 2016 and 2015 . The three levels of the fair value hierarchy under the Fair Value Measurement Topic of the ASC are: Level 1 - Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. Level 1 consists of financial assets and liabilities whose fair values are estimated using quoted market prices. Included in Level 1 are money market funds, certificates of deposit, commodities warehouse receipts, some common stock and American Depositary Receipts (“ADRs”), some exchangeable foreign ordinary equities (“GDRs”), some corporate and municipal bonds, physical precious metals, agricultural, and energy commodities, equity investments in exchange firms, some mutual funds, as well as futures and options on futures contracts traded on national exchanges, exchange-cleared swaps and options which are valued using exchange closing prices, OTC swaps and options contracts using quoted prices from national exchanges in which the Company executes transactions for customer and proprietary accounts, and OTC firm purchase and sale commitments related to our agricultural and energy commodities; Level 2 - Quoted prices for identical or similar assets or liabilities in markets that are less active, that is, markets in which there are few transactions for the asset or liability that are observable for substantially the full term. Included in Level 2 are those financial assets and liabilities for which fair values are estimated using models or other valuation methodologies. These models are primarily industry-standard models that consider various observable inputs, including time value, yield curve, volatility factors, observable current market and contractual prices for the underlying financial instruments, as well as other relevant economic measures. Included in Level 2 are U.S. and foreign government obligations, mortgage-backed securities, some common stock and ADRs, some GDRs, some corporate and municipal bonds, commodities leases, and OTC forwards, swaps, and options, and OTC firm purchase and sale commitments related to precious metals commodities; and Level 3 - Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). Level 3 comprises financial assets and liabilities whose fair value is estimated based on internally developed models or methodologies utilizing significant inputs that are not readily observable from objective sources. Included in Level 3 are common stock and ADRs, some corporate and municipal bonds, some other investments and contingent liabilities. The following tables set forth the Company’s financial and nonfinancial assets and liabilities accounted for at fair value, on a recurring basis, as of September 30, 2016 and September 30, 2015 by level in the fair value hierarchy. There were no assets or liabilities that were measured at fair value on a nonrecurring basis as of September 30, 2016 and 2015 . September 30, 2016 (in millions) Level 1 Level 2 Level 3 Netting and Total Assets: Unrestricted cash equivalents - certificates of deposits $ 7.1 $ — $ — $ — $ 7.1 Commodities warehouse receipts 23.3 — — — 23.3 U.S. government obligations — 595.5 — — 595.5 Securities and other assets segregated under federal and other regulations 23.3 595.5 — — 618.8 Money market funds 512.7 — — — 512.7 U.S. government obligations — 472.1 — — 472.1 Derivatives 2,149.9 — — (2,266.2 ) (116.3 ) Deposits and receivables from exchange-clearing organizations 2,662.6 472.1 — (2,266.2 ) 868.5 “To be announced” (TBA) and forward settling securities — 0.3 — — 0.3 Derivatives — 8.0 — (23.5 ) (15.5 ) Deposits and receivables from broker-dealers, clearing organizations and counterparties — 8.3 — (23.5 ) (15.2 ) Common and preferred stock and ADRs 34.6 1.7 0.2 — 36.5 Exchangeable foreign ordinary equities and ADRs 25.2 0.5 — — 25.7 Corporate and municipal bonds 36.9 0.9 3.0 — 40.8 U.S. government obligations — 514.9 — — 514.9 Foreign government obligations — 14.6 — — 14.6 Mortgage-backed securities — 747.5 — — 747.5 Derivatives 206.9 1,350.8 — (1,363.8 ) 193.9 Commodities leases — 137.2 — (129.1 ) 8.1 Commodities warehouse receipts 8.9 — — — 8.9 Exchange firm common stock 6.4 — — — 6.4 Mutual funds and other 8.8 — — — 8.8 Financial instruments owned 327.7 2,768.1 3.2 (1,492.9 ) 1,606.1 Physical commodities inventory 71.2 — — — 71.2 Total assets at fair value $ 3,091.9 $ 3,844.0 $ 3.2 $ (3,782.6 ) $ 3,156.5 Liabilities: Accounts payable and other accrued liabilities - contingent liabilities $ — $ — $ 0.8 $ — $ 0.8 TBA and forward settling securities — 2.6 — 0.9 3.5 Derivatives 1,961.7 97.5 — (2,059.2 ) — Payables to broker-dealers, clearing organizations and counterparties 1,961.7 100.1 — (2,058.3 ) 3.5 Common and preferred stock and ADRs 23.5 0.4 — — 23.9 Exchangeable foreign ordinary equities and ADRs 25.3 0.5 — — 25.8 Corporate and municipal bonds 6.9 — — — 6.9 U.S. government obligations — 509.8 — — 509.8 Foreign government obligations — — — — — Mortgage-backed securities — — — — — Derivatives 199.4 1,319.3 — (1,307.8 ) 210.9 Commodities leases — 207.8 — (145.7 ) 62.1 Financial instruments sold, not yet purchased 255.1 2,037.8 — (1,453.5 ) 839.4 Total liabilities at fair value $ 2,216.8 $ 2,137.9 $ 0.8 $ (3,511.8 ) $ 843.7 (1) Represents cash collateral and the impact of netting across the levels of the fair value hierarchy. Netting among positions classified within the same level are included in that level. September 30, 2015 (in millions) Level 1 Level 2 Level 3 Netting and Total Assets: Unrestricted cash equivalents - certificates of deposits $ 1.3 $ — $ — $ — $ 1.3 Commodities warehouse receipts 22.1 — — — 22.1 U.S. government obligations — 493.4 — — 493.4 Securities and other assets segregated under federal and other regulations 22.1 493.4 — — 515.5 Money market funds 431.8 — — — 431.8 U.S. government obligations — 501.4 — — 501.4 Derivatives 3,615.9 — — (3,539.7 ) 76.2 Deposits and receivables from exchange-clearing organizations 4,047.7 501.4 — (3,539.7 ) 1,009.4 TBA and forward settling securities — 1.2 — (1.0 ) 0.2 Derivatives 0.1 537.9 — (591.1 ) (53.1 ) Deposits and receivables from broker-dealers, clearing organizations and counterparties - derivatives 0.1 539.1 — (592.1 ) (52.9 ) Common and preferred stock and ADRs 23.7 1.9 0.5 — 26.1 Exchangeable foreign ordinary equities and ADRs 82.9 6.6 — — 89.5 Corporate and municipal bonds 26.1 2.0 3.2 — 31.3 U.S. government obligations — 513.4 — — 513.4 Foreign government obligations — 12.1 — — 12.1 Mortgage-backed securities — 699.5 — — 699.5 Derivatives 278.5 1,702.0 — (1,949.9 ) 30.6 Commodities leases — 64.6 — (57.0 ) 7.6 Commodities warehouse receipts 2.8 — — — 2.8 Exchange firm common stock 5.6 — — — 5.6 Mutual funds and other 3.4 — — — 3.4 Financial instruments owned 423.0 3,002.1 3.7 (2,006.9 ) 1,421.9 Physical commodities inventory 15.2 — — — 15.2 Total assets at fair value $ 4,509.4 $ 4,536.0 $ 3.7 $ (6,138.7 ) $ 2,910.4 Liabilities: Accounts payable and other accrued liabilities - contingent liabilities $ — $ — $ 3.3 $ — $ 3.3 TBA and forward settling securities — 2.6 — (1.0 ) 1.6 Derivatives 3,491.3 528.7 — (4,020.0 ) — Payable to broker-dealers, clearing organizations and counterparties - derivatives 3,491.3 531.3 — (4,021.0 ) 1.6 Common and preferred stock and ADRs 18.0 0.6 — — 18.6 Exchangeable foreign ordinary equities and ADRs 89.0 1.0 — — 90.0 U.S. government obligations — 341.0 — — 341.0 Foreign government obligations — 6.4 — — 6.4 Mortgage-backed securities — 2.8 — — 2.8 Derivatives 264.0 1,723.5 — (1,933.4 ) 54.1 Commodities leases — 99.1 — (43.7 ) 55.4 Financial instruments sold, not yet purchased 371.0 2,174.4 — (1,977.1 ) 568.3 Total liabilities at fair value $ 3,862.3 $ 2,705.7 $ 3.3 $ (5,998.1 ) $ 573.2 (1) Represents cash collateral and the impact of netting across the levels of the fair value hierarchy. Netting among positions classified within the same level are included in that level. Realized and unrealized gains and losses are included in ‘trading gains, net’ in the consolidated income statements. Information on Level 3 Financial Assets and Liabilities The Company’s financial assets at fair value classified within level 3 of the fair value hierarchy as of September 30, 2016 and 2015 are summarized below: (in millions) September 30, 2016 September 30, 2015 Total level 3 assets $ 3.2 $ 3.7 Level 3 assets for which the Company bears economic exposure $ 3.2 $ 3.7 Total assets $ 5,951.3 $ 5,070.0 Total financial assets at fair value $ 3,156.5 $ 2,910.4 Total level 3 assets as a percentage of total assets 0.1 % 0.1 % Level 3 assets for which the Company bears economic exposure as a percentage of total assets 0.1 % 0.1 % Total level 3 assets as a percentage of total financial assets at fair value 0.1 % 0.1 % The following tables set forth a summary of changes in the fair value of the Company’s level 3 financial assets and liabilities during the fiscal years ended September 30, 2016 and 2015 , including a summary of unrealized gains (losses) during the fiscal year ended on the Company’s level 3 financial assets and liabilities still held as of September 30, 2016 . Level 3 Financial Assets and Financial Liabilities (in millions) Balances at Realized gains Unrealized Purchases/ Settlements Transfers in Balances at Assets: Common and preferred stock and ADRs $ 0.5 $ — $ (0.3 ) $ — $ — $ — $ 0.2 Corporate and municipal bonds 3.2 — (0.2 ) — — — 3.0 $ 3.7 $ — $ (0.5 ) $ — $ — $ — $ 3.2 (in millions) Balances at Realized gains Remeasurement Acquisitions Settlements Transfers in Balances at Liabilities: Contingent liabilities $ 3.3 $ — $ 0.4 $ — $ (2.9 ) $ — $ 0.8 Level 3 Financial Assets and Financial Liabilities (in millions) Balances at Realized gains Unrealized Purchases/ Settlements Transfers in Balances at Assets: Common and preferred stock and ADRs $ 0.7 $ — $ (0.2 ) $ — $ — $ — $ 0.5 Corporate and municipal bonds 3.6 — (0.4 ) — — — 3.2 $ 4.3 $ — $ (0.6 ) $ — $ — $ — $ 3.7 (in millions) Balances at Realized gains Remeasurement Acquisitions Settlements Transfers in Balances at Liabilities: Contingent liabilities $ 5.5 $ — $ 1.8 $ 0.1 $ (4.1 ) $ — $ 3.3 In accordance with the Fair Value Measurement Topic of the ASC, the Company has estimated on a recurring basis each period the fair value of debentures issued by a single asset owning company of Suriwongse Hotel located in Chiang Mai, Thailand. As of September 30, 2016 , the Company’s investment in the hotel was $3.0 million , and included within the corporate and municipal bonds classification in the level 3 financial assets and financial liabilities tables. The Company classified its investment in the hotel within level 3 of the fair value hierarchy because the fair value was determined using significant unobservable inputs, which included projected cash flows. These cash flows were discounted employing present value techniques. The Company estimated the fair value of its investment in these debentures by using a management-developed forecast, which was based on the income approach. The Company continued to monitor the hotel renovation process and evaluate the fair value of the debentures. There had been no significant change in the fair value of the debentures, and no additional loss had been recognized during the years ended September 30, 2016, 2015 and 2014. In December 2016, the Company sold the debentures and collected an amount approximating their carrying value. The Company is required to make additional future cash payments based on certain financial performance measures of its acquired businesses. The Company is required to remeasure the fair value of the cash earnout arrangements on a recurring basis in accordance with the guidance in the Business Combinations Topic of the ASC. The Company has classified its liabilities for the contingent earnout arrangements within level 3 of the fair value hierarchy because the fair value is determined using significant unobservable inputs, which include projected cash flows. The estimated fair value of the contingent purchase consideration is based upon management-developed forecasts, a level 3 input in the fair value hierarchy. These cash flows are discounted employing present value techniques in arriving at fair value. The discount rate was developed using market participant company data and there have been no significant changes in the discount rate environment. From the dates of acquisition to September 30, 2016 , certain acquisitions have had changes in the estimates of undiscounted cash flows, based on actual performances fluctuating from estimates. During the fiscal years ended September 30, 2016 and 2015 , the fair value of the contingent consideration increased $0.4 million and decreased $1.8 million , respectively, with the corresponding income or expense classified as ‘other’ in the consolidated income statements. The value of an exchange-traded derivative contract is equal to the unrealized gain or loss on the contract determined by marking the contract to the current settlement price for a like contract on the valuation date of the contract. A settlement price may not be used if the market makes a limit move with respect to a particular derivative contract or if the securities underlying the contract experience significant price fluctuations after the determination of the settlement price. When a settlement price cannot be used, derivative contracts will be valued at their fair value as determined in good faith pursuant to procedures adopted by management of the Company. The Company reports transfers in and out of levels 1, 2 and 3, as applicable, using the fair value of the securities as of the beginning of the reporting period in which the transfer occurred. The Company did not have any additional significant transfers between level 1 and level 2 fair value measurements for the fiscal years ended September 30, 2016 and 2015 . The Company has classified equity investments in exchange firms’ common stock not pledged for clearing purposes as trading. The investments are recorded at fair value, with unrealized gains and losses recorded, net of taxes, included in earnings. As of September 30, 2016 , the cost and fair value of the equity investments in exchange firms is $3.7 million and $6.4 million , respectively. As of September 30, 2015 , the cost and fair value of the equity investments in exchange firms was $3.7 million and $5.6 million , respectively. In June 2015, the Company sold shares of common stock in the Intercontinental Exchange, Inc. (“ICE”). The Company was required to hold these ICE shares for clearing purposes and, as a result, the shares were being held at cost on the consolidated balance sheet. The Company recorded a receivable for the proceeds of $2.1 million , which was received in July 2015, and recognized a gain of $1.2 million before taxes, during the year ended September 30, 2015, in connection with the sale of these shares. For the fiscal year ended September 30, 2015, the Company reclassified the unrealized gain remaining in AOCI of approximately $3.3 million , net of income tax expense of $2.0 million , into earnings. During the year ended September 30, 2014, the Company sold all of its investments in mortgage-backed securities and the U.S. government obligations that were held as of September 30, 2014, matured, and as a result, realized gains of $0.1 million , net of tax, were reclassified from OCI for the year ended September 30, 2014. Except as discussed previously, there were no other sales of AFS Securities during years ended September 30, 2016 and September 30, 2015 , and as a result, no additional realized gains or losses were recorded for the years ended September 30, 2016 and September 30, 2015 .

Financial Instruments with Off-

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk (Notes)	12 Months Ended
	Sep. 30, 2016
Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk [Abstract]
Derivative Instruments and Hedging Activities Disclosure [Text Block]	Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk The Company is party to certain financial instruments with off-balance sheet risk in the normal course of its business. The Company has sold financial instruments that it does not currently own and will therefore be obliged to purchase such financial instruments at a future date. The Company has recorded these obligations in the consolidated financial statements as of September 30, 2016 at the fair values of the related financial instruments. The Company will incur losses if the fair value of the underlying financial instruments increases subsequent to September 30, 2016 . The total of $839.4 million as of September 30, 2016 includes $210.9 million for derivative contracts, which represent a liability to the Company based on their fair values as of September 30, 2016 . Derivatives The Company utilizes derivative products in its trading capacity as a dealer in order to satisfy customer needs and mitigate risk. The Company manages risks from both derivatives and non-derivative cash instruments on a consolidated basis. The risks of derivatives should not be viewed in isolation, but in aggregate with the Company’s other trading activities. The majority of the Company’s derivative positions are included in the consolidating balance sheets in ‘deposits and receivables from exchange-clearing organizations’, ‘financial instruments owned and sold, not yet purchased, at fair value’ and ‘payables to broker-dealers, clearing organizations and counterparties’. The Company employs an interest rate risk management strategy that uses derivative financial instruments in the form of interest rate swaps to manage a portion of the aggregate interest rate position. The Company’s objective is to invest the majority of customer segregated deposits in high quality, short-term investments and swap the resulting variable interest earnings into the medium-term interest stream. The risk mitigation of these interest rate swaps is not within the documented hedging designation requirements of the Derivatives and Hedging Topic of the ASC, and as a result they are recorded at fair value, with changes in the marked-to-market valuation of the financial instruments recorded within ‘trading gains, net’ in the consolidated income statements. At September 30, 2016 , the Company had $375 million in notional principal of interest rate swaps outstanding with a weighted-average life of 15 months. Listed below are the fair values of the Company’s derivative assets and liabilities as of September 30, 2016 and 2015 . Assets represent net unrealized gains and liabilities represent net unrealized losses. September 30, 2016 September 30, 2015 (in millions) Assets (1) Liabilities (1) Assets (1) Liabilities (1) Derivative contracts not accounted for as hedges: Exchange-traded commodity derivatives $ 2,022.1 $ 1,920.5 $ 3,443.6 $ 3,313.8 OTC commodity derivatives 1,217.0 1,188.9 1,621.2 1,650.7 Exchange-traded foreign exchange derivatives 12.2 7.5 27.8 20.6 OTC foreign exchange derivatives 346.5 290.2 892.2 865.4 Exchange-traded interest rate derivatives 78.7 120.5 126.8 136.0 Equity index derivatives 39.1 50.3 22.8 21.0 TBA and forward settling securities 0.3 2.6 1.2 2.6 Gross fair value of derivative contracts 3,715.9 3,580.5 6,135.6 6,010.1 Impact of netting and collateral (3,653.5 ) (3,366.1 ) (6,081.7 ) (5,954.4 ) Total fair value included in ‘Deposits and receivables from exchange-clearing organizations’ $ (116.3 ) $ 76.2 Total fair value included in ‘Deposits and receivables from broker-dealers, clearing organizations and counterparties’ $ (15.2 ) $ (52.9 ) Total fair value included in ‘Financial instruments owned, at fair value’ $ 193.9 $ 30.6 Total fair value included in ‘Payables to broker-dealers, clearing organizations and counterparties $ 3.5 $ 1.6 Fair value included in ‘Financial instruments sold, not yet purchased, at fair value’ $ 210.9 $ 54.1 (1) As of September 30, 2016 and 2015 , the Company’s derivative contract volume for open positions was approximately 4.0 million and 4.1 million contracts, respectively. The Company’s derivative contracts are principally held in its Commodities and Risk Management Services (“Commercial Hedging”) segment. The Company assists its Commercial Hedging segment customers in protecting the value of their future production by entering into option or forward agreements with them on an OTC basis. The Company also provides its Commercial Hedging segment customers with option products, including combinations of buying and selling puts and calls. The Company mitigates its risk by generally offsetting the customer’s transaction simultaneously with one of the Company’s trading counterparties or will offset that transaction with a similar but not identical position on the exchange. The risk mitigation of these offsetting trades is not within the documented hedging designation requirements of the Derivatives and Hedging Topic of the ASC. These derivative contracts are traded along with cash transactions because of the integrated nature of the markets for these products. The Company manages the risks associated with derivatives on an aggregate basis along with the risks associated with its proprietary trading and market-making activities in cash instruments as part of its firm-wide risk management policies. In particular, the risks related to derivative positions may be partially offset by inventory, unrealized gains in inventory or cash collateral paid or received. Through its Rates Division, the Company transacts in derivative instruments, which consist of futures, mortgage-backed TBA securities and forward settling transactions, that are used to manage risk exposures. The fair value of these transactions is recorded in receivables or payables to broker-dealers, clearing organizations and counterparties. Realized and unrealized gains and losses on securities and derivative transactions are reflected in ‘trading gains, net’. The Company enters into TBA securities transactions for the sole purpose of managing risk associated with the purchase of mortgage pass-through securities. TBA securities are included within payables to broker-dealers, clearing organizations and counterparties. Forward settling securities represent non-regular way securities and are included in financial instruments owned and sold. As of September 30, 2016 , these transactions are summarized as follows (in millions): Gain / (Loss) Notional Amounts Unrealized gain on TBA securities purchased within payables to broker-dealers, clearing organizations and counterparties and related notional amounts (1) $ 0.8 $ 289.8 Unrealized loss on TBA securities purchased within payables to broker-dealers, clearing organizations and counterparties and related notional amounts (1) $ (0.8 ) $ 485.5 Unrealized gain on TBA securities sold within payables to broker-dealers, clearing organizations and counterparties and related notional amounts (1) $ 1.3 $ (702.3 ) Unrealized loss on TBA securities sold within payables to broker-dealers, clearing organizations and counterparties and related notional amounts (1) $ (1.7 ) $ (754.3 ) Unrealized gain on forward settling securities purchased within receivables from broker-dealers, clearing organizations and counterparties and related notional amounts $ 0.1 $ 607.9 Unrealized gain on forward settling securities sold within receivables from broker-dealers, clearing organizations and counterparties and related notional amounts $ 0.2 $ (470.4 ) (1) The notional amounts of these instruments reflect the extent of the Company’s involvement in TBA securities and do not represent risk of loss due to counterparty non-performance. The following table sets forth the Company’s net gains (losses) related to derivative financial instruments for the fiscal years ended September 30, 2016, 2015, and 2014 , in accordance with the Derivatives and Hedging Topic of the ASC. The net gains (losses) set forth below are included in ‘trading gains, net’ in the consolidated income statements. Year Ended September 30, (in millions) 2016 2015 2014 Commodities $ 41.8 $ 78.6 $ 65.7 Foreign exchange 9.7 7.5 7.5 Interest rate and equity 0.8 3.2 — TBA and forward settling securities (14.4 ) (5.1 ) — Net gains from derivative contracts $ 37.9 $ 84.2 $ 73.2 Credit Risk In the normal course of business, the Company purchases and sells financial instruments, commodities and foreign currencies as either principal or agent on behalf of its customers. If either the customer or counterparty fails to perform, the Company may be required to discharge the obligations of the nonperforming party. In such circumstances, the Company may sustain a loss if the fair value of the financial instrument or foreign currency is different from the contract value of the transaction. The majority of the Company’s transactions and, consequently, the concentration of its credit exposure are with commodity exchanges, customers, broker-dealers and other financial institutions. These activities primarily involve collateralized and uncollateralized arrangements and may result in credit exposure in the event that a counterparty fails to meet its contractual obligations. The Company’s exposure to credit risk can be directly impacted by volatile financial markets, which may impair the ability of counterparties to satisfy their contractual obligations. The Company seeks to control its credit risk through a variety of reporting and control procedures, including establishing credit limits based upon a review of the counterparties’ financial condition and credit ratings. The Company monitors collateral levels on a daily basis for compliance with regulatory and internal guidelines and requests changes in collateral levels as appropriate. The Company is a party to financial instruments in the normal course of its business through customer and proprietary trading accounts in exchange-traded and OTC derivative instruments. These instruments are primarily the execution of orders for commodity futures, options on futures and forward foreign currency contracts on behalf of its customers, substantially all of which are transacted on a margin basis. Such transactions may expose the Company to significant credit risk in the event margin requirements are not sufficient to fully cover losses which customers may incur. The Company controls the risks associated with these transactions by requiring customers to maintain margin deposits in compliance with individual exchange regulations and internal guidelines. The Company monitors required margin levels daily and, therefore, may require customers to deposit additional collateral or reduce positions when necessary. The Company also establishes credit limits for customers, which are monitored daily. The Company evaluates each customer’s creditworthiness on a case by case basis. Clearing, financing, and settlement activities may require the Company to maintain funds with or pledge securities as collateral with other financial institutions. Generally, these exposures to both customers and exchanges are subject to master netting, or customer agreements, which reduce the exposure to the Company by permitting receivables and payables with such customers to be offset in the event of a customer default. Management believes that the margin deposits held as of September 30, 2016 and September 30, 2015 were adequate to minimize the risk of material loss that could be created by positions held at that time. Additionally, the Company monitors collateral fair value on a daily basis and adjusts collateral levels in the event of excess market exposure. Generally, these exposures to both customers and counterparties are subject to master netting, or customer agreements which reduce the exposure to the Company. Derivative financial instruments involve varying degrees of off-balance sheet market risk whereby changes in the fair values of underlying financial instruments may result in changes in the fair value of the financial instruments in excess of the amounts reflected in the consolidated balance sheets. Exposure to market risk is influenced by a number of factors, including the relationships between the financial instruments and the Company’s positions, as well as the volatility and liquidity in the markets in which the financial instruments are traded. The principal risk components of financial instruments include, among other things, interest rate volatility, the duration of the underlying instruments and changes in commodity pricing and foreign exchange rates. The Company attempts to manage its exposure to market risk through various techniques. Aggregate market limits have been established and market risk measures are routinely monitored against these limits.

Receivables from customers, net

Receivables from customers, net and notes receivable, net (Notes)	12 Months Ended
	Sep. 30, 2016
Receivables from customers and notes receivable, net [Abstract]
Receivables from Customers and Notes Receivable [Text Block]	Receivables From Customers, Net and Notes Receivable, Net Receivables from customers, net and notes receivable, net include an allowance for bad debts, which reflects the Company’s best estimate of probable losses inherent in the receivables from customers and notes receivable. The Company provides for an allowance for doubtful accounts based on a specific-identification basis. The Company continually reviews its allowance for bad debts. The allowance for doubtful accounts related to receivables from customers was $9.5 million and $10.2 million as of September 30, 2016 and 2015 , respectively. The allowance for doubtful accounts related to notes receivable was $0.2 million and $1.0 million as of September 30, 2016 and 2015 , respectively. During the year ended September 30, 2016 , the Company recorded bad debt expense, net of recoveries, of $4.4 million , including provision increases of $4.2 million and direct write-offs of $0.4 million , offset by recoveries of $0.2 million . The increase in bad debts during fiscal 2016 primarily related to $3.6 million of customer deficits in the Commercial Hedging segment, $0.4 million of uncollectible customer receivables in the Physical Commodities segment and $0.4 million of uncollectible service fees and notes in the Securities segment. During the year ended September 30, 2015, the Company recorded bad debt expense, net of recoveries, of $7.3 million , including provision increases of $6.6 million and direct write-offs of $0.7 million , offset by minimal recoveries. The increase in bad debts during fiscal 2015 related to $2.8 million of receivables from a renewable fuels customer in the Physical Commodities segment, $2.3 million of OTC customer deficits and $0.6 million of LME customer deficits in the Commercial Hedging segment, $0.5 million of uncollectible service fees and notes in our Securities segment, and $1.1 million of notes receivable related to loans pertaining to a former acquisition. During the year ended September 30, 2014, the Company recorded bad debt expense, net of recoveries, of $5.5 million , including provision increases of $5.1 million and direct write-offs of $0.6 million , offset by recoveries of $0.2 million . The provision increases during fiscal 2014 was $3.8 million in the Commercial Hedging segment, primarily related to account deficits from a Hong Kong commercial LME customer and Brazilian OTC Financial Ag & Energy customers. Additionally, the Company recorded bad debts of $0.9 million in the Physical Commodities segment, related to renewable fuels activity, and $0.7 million in the Securities segment primarily related to charge-offs of uncollectible service fees. Activity in the allowance for doubtful accounts and notes for the years ended September 30, 2016, 2015, and 2014 was as follows: (in millions) 2016 2015 2014 Balance, beginning of year $ 11.2 $ 5.8 $ 1.2 Provision for bad debts 4.2 6.0 5.3 Deductions: Charge-offs (5.7 ) (0.6 ) (0.7 ) Balance, end of year $ 9.7 $ 11.2 $ 5.8 The Company originates short-term notes receivable from customers with the outstanding balances typically being insured 90% to 98% by a third party, including accrued interest, subject to applicable deductible amounts. The total balance outstanding under insured notes receivable was $5.0 million and $41.4 million as of September 30, 2016 and 2015 , respectively. The Company has sold $4.6 million and $30.7 million of the insured portion of the notes through non-recourse participation agreements with other third parties as of September 30, 2016 and 2015 , respectively. The Company has completed its exit of the majority of this activity during the year ended September 30, 2016. The Company believes the run-off of the remaining activity will have a minimal impact on the Company. See discussion of notes receivable related to commodity repurchase agreements in Note 13 .

Physical Commodities Inventory

Physical Commodities Inventory (Notes)	12 Months Ended
	Sep. 30, 2016
Physical Commodities Inventory [Abstract]
Inventory Disclosure [Text Block]	Physical Commodities Inventory The Company’s inventories consist of finished physical commodities. Inventories by component of the Company’s Physical Commodities segment are shown below. (in millions) September 30, September 30, Physical Ag & Energy (1) $ 65.9 $ 0.4 Precious metals - held by broker-dealer subsidiary (2) 5.3 10.8 Precious metals - held by non-broker-dealer subsidiaries (3) 52.6 21.6 Physical commodities inventory $ 123.8 $ 32.8 (1) Physical Ag & Energy maintains agricultural commodity inventories, including corn, soybeans, wheat, dried distillers grain, canola, sorghum, coffee and others. The agricultural commodity inventories are carried at net realizable value, which approximates fair value less disposal costs, with changes in net realizable value included as a component of ‘cost of sales of physical commodities’ on the consolidated income statement. The agricultural inventories have reliable, readily determinable and realizable market prices, have relatively insignificant costs of disposal and are available for immediate delivery. (2) Precious metals held by the Company’s subsidiary, INTL FCStone Ltd, a United Kingdom based broker-dealer subsidiary, is measured at fair value, with changes in fair value included as a component of ‘trading gains, net’ on the consolidated income statement, in accordance with U.S. GAAP accounting requirements for broker-dealers. (3) Precious metals inventory held by subsidiaries that are not broker-dealers are valued at the lower of cost or market value. The Company has recorded lower of cost or market (“LCM”) adjustments for certain precious metals inventory of $0.6 million and $0.3 million as of September 30, 2016 and 2015 , respectively. The adjustments are included in ‘cost of sales of physical commodities’ in the consolidated income statements.

Property and Equipment, net (No

Property and Equipment, net (Notes)	12 Months Ended
	Sep. 30, 2016
Property and Equipment, net [Abstract]
Property, Plant and Equipment Disclosure [Text Block]	Property and Equipment, net Property and equipment are stated at cost, and reported net of accumulated depreciation on the consolidated balance sheets. Depreciation on plant and equipment is calculated on the straight-line method over the estimated useful lives of the assets. The estimated useful lives of property and equipment range from 3 to 10 years. During the fiscal years ended September 30, 2016, 2015, and 2014 , depreciation expense was $6.6 million , $5.7 million and $5.7 million , respectively. A summary of property and equipment, at cost less accumulated depreciation as of September 30, 2016 and 2015 is as follows: (in millions) September 30, 2016 September 30, 2015 Property and equipment: Furniture and fixtures $ 6.8 $ 5.2 Software 22.8 9.0 Equipment 20.6 16.1 Leasehold improvements 11.9 9.9 Total property and equipment 62.1 40.2 Less accumulated depreciation (32.7 ) (20.5 ) Property and equipment, net $ 29.4 $ 19.7

Goodwill (Notes)

Goodwill (Notes)	12 Months Ended
	Sep. 30, 2016
Goodwill [Abstract]
Goodwill Disclosure [Text Block]	Goodwill Goodwill allocated to the Company’s operating segments as of September 30, 2016 and 2015 is as follows: (in millions) September 30, September 30, Commercial Hedging $ 30.7 $ 30.7 Global Payments 6.3 6.3 Physical Commodities 2.4 2.4 Securities 8.1 8.1 Goodwill $ 47.5 $ 47.5

Intangible Assets (Notes)

Intangible Assets (Notes)	12 Months Ended
	Sep. 30, 2016
Intangible Assets [Abstract]
Intangible Assets Disclosure [Text Block]	Intangible Assets The gross and net carrying values of intangible assets as of the balance sheet dates, by major intangible asset class are as follows: September 30, 2016 September 30, 2015 (in millions) Gross Amount Accumulated Amortization Net Amount Gross Amount Accumulated Amortization Net Amount Intangible assets subject to amortization: Trade name $ 1.1 $ (0.6 ) $ 0.5 $ — $ — $ — Software programs/platforms 2.7 (2.4 ) 0.3 2.7 (2.3 ) 0.4 Customer base 14.0 (5.7 ) 8.3 14.0 (4.9 ) 9.1 17.8 (8.7 ) 9.1 16.7 (7.2 ) 9.5 Intangible assets not subject to amortization: Trade name — — — 1.1 — 1.1 Total intangible assets $ 17.8 $ (8.7 ) $ 9.1 $ 17.8 $ (7.2 ) $ 10.6 During the year ended September 30, 2016, as part of the periodic assessment of useful lives of the intangible assets, the Company determined the indefinite-lived trade names, related to the Risk Management Incorporated and RMI Consulting, Inc. (the “RMI Companies”) acquisitions, were no longer considered to be indefinite. The Company is intending to phase out the use of those trade names in the future. The value of the RMI Companies’ trade names of $1.1 million was recorded in the Commercial Hedging segment. The RMI Companies’ trade names were determined to have a remaining finite useful life of approximately two years. The trade names were not deemed to be impaired, however, the value of the trade names was transferred from the indefinite-lived category to intangible assets subject to amortization over the estimated two year useful life. The Company recorded amortization for the trade names of $0.6 million , within ‘depreciation and amortization’ on the consolidated income statements, during the year ended September 30, 2016. Amortization expense related to intangible assets was $1.6 million , $1.5 million , and $1.6 million for the fiscal years ended September 30, 2016, 2015, and 2014 , respectively. The estimated future amortization expense as of September 30, 2016 is as follows (in millions): Year ending September 30, 2017 $ 1.6 2018 1.0 2019 1.0 2020 0.8 2021 and thereafter 4.7 $ 9.1

Credit Facilities (Notes)

Credit Facilities (Notes)	12 Months Ended
	Sep. 30, 2016
Credit Facilities [Abstract]
Debt Disclosure [Text Block]	Credit Facilities Variable-Rate Credit Facilities The Company has four committed credit facilities under which the Company and its subsidiaries may borrow up to $447.0 million , subject to the terms and conditions for these facilities. The amounts outstanding under these credit facilities are short term borrowings and carry variable rates of interest, thus approximating fair value. The Company’s credit facilities are as follows: A three-year syndicated committed loan facility established on September 30, 2013 and amended on March 18, 2016 and September 15, 2016, under which $247 million is available to the Company for general working capital requirements. The line of credit is secured by a pledge of shares held in certain of the Company’s subsidiaries. Unused portions of the loan facility require a commitment fee of 0.625% on the unused commitment. Borrowings under the facility bear interest at the Eurodollar Rate, as defined, plus 3.00% or Base Rate, as defined, plus 2.00% , and averaged 5.25% as of September 30, 2016. The agreement contains financial covenants related to consolidated tangible net worth, consolidated funded debt to net worth ratio, consolidated fixed charge coverage ratio and consolidated net unencumbered liquid assets, as defined. The Company was in compliance with these financial covenants as of September 30, 2016 . The agreement also includes a non-financial covenant limiting the amount of annual consolidated capital expenditures to $15.0 million. The Company’s annual consolidated expenditures were in excess of this amount during fiscal 2016. The Company requested and was granted a waiver from the lenders, dated December 8, 2016, for the excess amount acquired during fiscal 2016. The Company paid debt issuance costs of $1.8 million in connection with the issuance of this credit facility, which are being amortized over the thirty-six month term of the facility. An unsecured syndicated committed line of credit, established on June 21, 2010 and renewed by amendment on March 16, 2016, under which $75 million is available to the Company’s subsidiary, INTL FCStone Financial to provide short term funding of margin to commodity exchanges as necessary. This line of credit is subject to annual review, and the continued availability of this line of credit is subject to INTL FCStone Financial’s financial condition and operating results continuing to be satisfactory as set forth in the agreement. Unused portions of the margin line require a commitment fee of 0.50% on the unused commitment. Borrowings under the margin line are on a demand basis and bear interest at the Base Rate, as defined, plus 2.00% , which was 5.50% as of September 30, 2016 . The agreement contains financial covenants related to INTL FCStone Financial’s tangible net worth, excess net capital and maximum net loss over a trailing twelve month period, as defined. INTL FCStone Financial was in compliance with these covenants as of September 30, 2016 . The facility is guaranteed by the Company. A syndicated committed borrowing facility established on March 15, 2016, and amended on November 14, 2016, under which $100.0 million is available to the Company’s subsidiary, FCStone Merchant Services, LLC (“FCStone Merchants”) for financing traditional commodity financing arrangements and commodity repurchase agreements. The facility is secured by the assets of FCStone Merchants, and guaranteed by the Company. Unused portions of the borrowing facility require a commitment fee of 0.50% on the unused commitment. The borrowings outstanding under the facility bear interest at a rate per annum equal to the Base Rate plus Applicable Margin, as defined, which averaged 4.25% as of September 30, 2016 . The agreement contains financial covenants related to tangible net worth, as defined. FCStone Merchants was in compliance with this covenant as of September 30, 2016 . FCStone Merchants paid minimal debt issuance costs in connection with this credit facility. A syndicated committed borrowing facility established on November 15, 2013, and renewed by amendment on October 27, 2016, under which $25.0 million is available to the Company’s subsidiary, INTL FCStone Ltd for short term funding of margin to commodity exchanges. The borrowings outstanding under the facility bear interest at a rate per annum equal to 2.50% plus the Federal Funds Rate, as defined. The agreement contains financial covenants related to consolidated tangible net worth, as defined. INTL FCStone Ltd was in compliance with this covenant as of September 30, 2016 . INTL FCStone Ltd paid minimal debt issuance costs in connection with this credit facility. The facility is guaranteed by the Company. The Company also has a secured, uncommitted loan facility, under which the Company’s wholly owned subsidiary, INTL FCStone Financial may borrow up to $50.0 million , collateralized by commodity warehouse receipts, to facilitate U.S. commodity exchange deliveries of its customers, subject to certain terms and conditions of the credit agreement. The Company also has a secured, uncommitted loan facility, under which the Company’s wholly owned subsidiary, INTL FCStone Ltd may borrow up to approximately $25.0 million , collateralized by commodity warehouse receipts, to facilitate financing of commodities under repurchase agreement services to its customers, subject to certain terms and conditions of the credit agreement. In connection with the acquisition of the Sterne businesses discussed in Note 18, the Company assumed two uncommitted secured lines of credit under which the Company may borrow for short term funding of firm and customer margin requirements. The facilities bear interest at a rate per annum equal to such rate in respect of such day as determined by the bank in its sole discretion. In the event that the Company fails to pay the principal and interest on the scheduled due date, the facilities bear penalty interest at a rate equal to the Federal Funds rate plus 2% . The amounts borrowed under the facilities are payable on demand. As of September 30, 2016 , the Company had no borrowings against these lines. Note Payable to Bank In April 2015, the Company obtained a $4.0 million loan from a commercial bank, secured by equipment purchased with the proceeds. The note is payable in monthly installments, ending in March 2020. The note bears interest at a rate per annum equal to LIBOR plus 2.00%. Senior Unsecured Notes In July 2013, the Company completed the offering of $45.5 million aggregate principal amount of the Company’s 8.5% Senior Notes due 2020 (the “Notes”). The net proceeds of the sale of the Notes were being used for general corporate purposes. The Notes bore interest at a rate of 8.5% per year (payable quarterly on January 30, April 30, July 30 and October 30 of each year). The Notes were scheduled to mature on July 30, 2020. The Company could redeem the Notes, in whole or in part, at any time on and after July 30, 2016, at a redemption price equal to 100% of the principal amount redeemed plus accrued and unpaid interest to, but not including, the redemption date. The Company incurred debt issuance costs of $1.7 million in connection with the issuance of the Notes, which were being amortized over the term of the Notes. On September 15, 2016, the Company provided notice, through the trustee of the Notes, to the record holders of the Notes that the Company would redeem the outstanding $45.5 million aggregate principal amount of the Notes in full. Pursuant to the terms of the Indenture, the Company redeemed the Notes at a price equal to 100% of the principal amount redeemed plus accrued and unpaid interest to, but not including, the redemption date on October 15, 2016. The following table sets forth a listing of credit facilities, the current committed amounts, as of the report date, on the facilities, and outstanding borrowings on the facilities as well as indebtedness on a promissory note an on senior notes as of September 30, 2016 and 2015 : (in millions) Credit Facilities Amounts Outstanding Borrower Security Renewal / Expiration Date Total Commitment September 30, September 30, INTL FCStone Inc. Certain pledged shares of certain subsidiaries March 18, 2019 $ 247.0 $ 136.5 $ 28.0 INTL FCStone Financial None April 6, 2017 75.0 — — INTL FCStone Financial Commodity warehouse receipts n/a — — — FCStone Merchants Certain commodities assets May 1, 2018 100.0 43.5 10.0 INTL FCStone Ltd None October 27, 2017 25.0 — — $ 447.0 180.0 38.0 Note Payable to Bank Monthly installments, due March 2020 and secured by certain equipment 2.8 3.6 Senior Unsecured Notes 8.50% senior notes, redeemed October 15, 2016 45.5 45.5 Total indebtedness $ 228.3 $ 87.1 As reflected above, $75 million of the Company’s committed credit facilities are scheduled to expire during the fiscal year ended September 30, 2017. The Company intends to renew or replace these facilities as they expire, and based on the Company’s liquidity position and capital structure, the Company believes it will be able to do so.

Commitments and Contingencies (

Commitments and Contingencies (Notes)	12 Months Ended
	Sep. 30, 2016
Commitments and Contingencies [Abstract]
Commitments and Contingencies Disclosure [Text Block]	Commitments and Contingencies Legal Proceedings Certain conditions may exist as of the date the financial statements are issued, which may result in a loss to the Company but which will only be resolved when one or more future events occur or fail to occur. The Company assesses such contingent liabilities, and such assessment inherently involves an exercise of judgment. In assessing loss contingencies related to legal proceedings that are pending against the Company or unasserted claims that may result in such proceedings, the Company’s legal counsel evaluates the perceived merits of any legal proceedings or unasserted claims as well as the perceived merits of the amount of relief sought or expected to be sought therein. If the assessment of a contingency indicates that it is probable that a material loss had been incurred at the date of the financial statements and the amount of the liability can be estimated, then the estimated liability would be accrued in the Company’s financial statements. If the assessment indicates that a potentially material loss contingency is not probable, but is reasonably possible, or is probable but cannot be estimated, then the nature of the contingent liability, together with an estimate of the range of possible loss if determinable and material, would be disclosed. Neither accrual nor disclosure is required for loss contingencies that are deemed remote. The Company accrues legal fees related to contingent liabilities as they are incurred. In addition to the matters discussed below, from time to time and in the ordinary course of business, the Company is involved in various legal actions and proceedings, including tort claims, contractual disputes, employment matters, workers’ compensation claims and collections. The Company carries insurance that provides protection against certain types of claims, up to the policy limits of the insurance. As of September 30, 2016 and 2015 , the consolidated balance sheets include loss contingency accruals, recorded during and prior to these fiscal years then ended, which are not material, individually or in the aggregate, to the Company’s financial position or liquidity. In the opinion of management, possible exposure from loss contingencies in excess of the amounts accrued, and in addition to the possible losses discussed below, is not material to the Company’s earnings, financial position or liquidity. The following is a summary of a significant legal matter involving the Company. Sentinel Litigation Prior to its July 1, 2015 merger into INTL FCStone Financial, the Company’s subsidiary FCStone, LLC, had a portion of its excess segregated funds invested with Sentinel Management Group Inc. (“Sentinel”), a registered FCM and an Illinois-based money manager that provided cash management services to other FCMs. In August 2007, Sentinel halted redemptions to customers and sold certain of the assets it managed to an unaffiliated third party at a significant discount. On August 17, 2007, subsequent to Sentinel’s sale of certain assets, Sentinel filed for bankruptcy protection. In aggregate, $15.5 million of FCStone, LLC’s $21.9 million in invested funds were returned to it before and after Sentinel’s bankruptcy petition. In August 2008, the bankruptcy trustee of Sentinel filed adversary proceedings against FCStone, LLC, and a number of other FCMs in the Bankruptcy Court for the Northern District of Illinois. The case was subsequently reassigned to the U.S. District Court, for the Northern District of Illinois. In the complaint, the trustee sought avoidance of alleged transfers or withdrawals of funds received by FCStone, LLC and other FCMs within 90 days prior to the filing of the Sentinel bankruptcy petition, as well as avoidance of post-petition distributions and disallowance of the proof of claim filed by FCStone, LLC. The trustee sought recovery of pre- and post-petition transfers totaling approximately $15.5 million . The trial of this matter took place, as a test case, during October 2012. The trial court entered a judgment against FCStone, LLC on January 4, 2013. On January 17, 2013, the trial court entered an agreed order, staying execution and enforcement, pending an appeal of the judgment. On March 19, 2014, the appeal court ruled in favor of FCStone, LLC. On April 16, 2014, the trustee filed a petition for rehearing of the appeal. On May 19, 2014, the U.S. Court of Appeals for the Seventh Circuit denied the petition. The trustee did not file a writ for certiorari with the U.S. Supreme Court during the time allotted to do so. On February 10, 2015, based on a new theory, the trustee filed a motion for judgment against FCStone, LLC in the U.S. District Court, for the Northern District of Illinois, seeking to claw back the post-petition transfer of $14.5 million and to recover the funds held in reserve in the name of FCStone, LLC. FCStone, LLC filed its opposition brief and an associated motion for judgment on March 17, 2015. The trustee filed its reply briefs on April 7, 2015 and the Company filed its reply briefs on April 22, 2015. On March 28, 2016 the U.S. District Court for the Northern District of Illinois entered an order in favor of FCStone, LLC (now INTL FCStone Financial Inc.) and against the trustee on the trustee’s post-petition claim, in light of the Seventh Circuit’s opinion. The same court ruled against INTL FCStone Financial and in favor of the trustee with respect to the funds held in reserve accounts. On April 25, 2016, INTL FCStone Financial filed a notice of appeal to the U.S. Court of Appeals for the Seventh Circuit relating to the portion of the final judgment dated March 28, 2016 of the district court and INTL FCStone Financial’s claim to funds in reserve accounts. On April 26, 2016, the trustee filed a notice of appeal from the March 28, 2016 final judgment of the district court. On April 27, 2016, the court consolidated the two appeals and directed the trustee to file an opening brief. On June 27, 2016 the trustee filed his appellate brief. On August 31, 2016, the Futures Industry Association, Inc. filed a voluntary brief in support of INTL FCStone Financial’s cross-appeal. The Company has determined that losses related to this matter are neither probable nor reasonably possible. The Company believes the case is without merit and intends to defend itself vigorously. Our assessments are based on estimates and assumptions that have been deemed reasonable by management, but that may later prove to be incomplete or inaccurate, and unanticipated events and circumstances may occur that might cause us to change those estimates and assumptions. Contractual Commitments Contingent Liabilities - Acquisitions Under the terms of the purchase agreement, related to the acquisitions listed below, the Company has an obligation to pay additional consideration if specific conditions and earnings targets are met. In accordance with the Business Combinations Topic of the ASC, the fair value of the additional consideration is recognized as a contingent liability as of the acquisition date. The contingent liability for these estimated additional purchase price considerations of $0.8 million and $3.3 million are included in ‘accounts payable and other accrued liabilities’ in the consolidated balance sheets as of September 30, 2016 and 2015 , respectively. The acquisition date fair value of additional consideration is remeasured to its fair value each reporting period, with changes in fair value recorded in current earnings. The change in fair value during the years ended September 30, 2016, 2015, and 2014 were an increase of $0.4 million , increase of $1.8 million and decrease of $2.3 million , respectively, and are included in ‘other’ in the consolidated income statements. The Company has a contingent liability relating to the January 2015 acquisition of G.X. Clarke, which may result in the payment of additional purchase price consideration. The contingent consideration in no event shall exceed $1.5 million . The estimated total purchase price, including contingent consideration, is $27.5 million as of September 30, 2016 , of which $0.8 million remains outstanding and is included in ‘accounts payable and other accrued liabilities’ in the consolidated balance sheet. Operating Leases The Company is obligated under various noncancelable operating leases for the rental of office facilities, automobiles, service obligations and certain office equipment, and accounts for these lease obligations on a straight line basis. The expense associated with operating leases amounted to $9.9 million , $10.1 million and $9.5 million , for fiscal years ended September 30, 2016, 2015, and 2014 , respectively. The expenses associated with the operating leases and service obligations are reported in the consolidated income statements in ‘occupancy and equipment rental’, ‘transaction-based clearing expenses’ and ‘other’ expenses. Future aggregate minimum lease payments under noncancelable operating leases as of September 30, 2016 are as follows: (in millions) Year ending September 30, 2017 $ 8.8 2018 7.1 2019 6.6 2020 6.3 2021 5.5 Thereafter 10.5 $ 44.8 Purchase Commitments The Company determines an estimate of contractual purchase commitments in the ordinary course of business primarily for the purchase of precious metals and agricultural and energy commodities. Unpriced contract commitments have been estimated using September 30, 2016 fair values. The purchase commitments and other obligations as of September 30, 2016 for less than one year, one to three years and three to five years were $603.5 million , $2.4 million and $1.7 million , respectively. There were $2.0 million in purchase commitments and other obligations after five years as of September 30, 2016 . The purchase commitments for less than one year will be partially offset by corresponding sales commitments of $475.9 million . Exchange Member Guarantees The Company is a member of various exchanges that trade and clear futures and option contracts. In connection with the Sterne acquisition, the Company is also a member of and provides guarantees to securities clearinghouses and exchanges in connection with customer trading activities. Associated with its memberships, the Company may be required to pay a proportionate share of the financial obligations of another member who may default on its obligations to the exchanges. While the rules governing different exchange memberships vary, in general the Company’s guarantee obligations would arise only if the exchange had previously exhausted its resources. In addition, any such guarantee obligation would be apportioned among the other non-defaulting members of the exchange. Any potential contingent liability under these arrangements is not quantifiable and could exceed the cash and securities it has posted to the clearinghouse as collateral. The Company has not recorded any contingent liability in the consolidated financial statements for these agreements and believes that any potential requirement to make payments under these agreements is remote. Self-Insurance The Company self-insures its costs related to medical and dental claims. The Company is self-insured, up to a stop loss amount, for eligible participating employees and retirees, and for qualified dependent medical and dental claims, subject to deductibles and limitations. Liabilities are recognized based on claims filed and an estimate of claims incurred but not reported. The Company has purchased stop-loss coverage to limit its exposure on a per claim basis and in aggregate in the event that aggregated actual claims would exceed 120% of actuarially estimated claims. The Company is insured for covered costs in excess of these limits. Although the ultimate outcome of these matters may exceed the amounts recorded and additional losses may be incurred, the Company does not believe that any additional potential exposure for such liabilities will have a material adverse effect on the Company’s consolidated financial position or results of operations. As of September 30, 2016 and 2015 , the Company had $1.0 million and $0.8 million , respectively, accrued for self-insured medical and dental claims included in ‘accounts payable and other liabilities’ in the consolidated balance sheets.

Regulatory Requirements and Sub

Regulatory Requirements and Subsidiary Dividend Restrictions (Notes)	12 Months Ended
	Sep. 30, 2016
Capital and Other Regulatory Requirements [Abstract]
Regulatory Capital Requirements under Banking Regulations [Text Block]	Regulatory Requirements and Subsidiary Dividend Restrictions The Company’s subsidiary INTL FCStone Financial is registered as a broker dealer and member of the Financial Industry Regulatory Authority (“FINRA”) subject to the SEC Uniform Net Capital Rule 15c3-1, which requires the maintenance of minimum net capital. INTL FCStone Financial is also a commodity futures commission merchant registered with the CFTC and subject to the net capital requirements of the CFTC Regulation 1.17. Under the more restrictive of these rules, INTL FCStone Financial is required to maintain “adjusted net capital”, equivalent to the greater of $1,000,000 or 8 percent of customer and noncustomer risk maintenance margin requirements on all positions, as defined in such rules, regulations, and requirements. Net capital and the related net capital requirement may fluctuate on a daily basis. INTL FCStone Financial also has restriction on dividends, which restricts the withdrawal of equity capital if the planned withdrawal would reduce net capital, subsequent to haircuts and charges, to an amount less than 120% of the greatest minimum requirement. Pursuant to the requirements of the Commodity Exchange Act, funds deposited by customers of INTL FCStone Financial relating to their trading of futures and options on futures on a U.S. commodities exchange must be carried in separate accounts which are designated as segregated customers’ accounts. Pursuant to the requirements of the CFTC, funds deposited by customers of INTL FCStone Financial relating to their trading of futures and options on futures traded on, or subject to the rules of, a foreign board of trade must be carried in separate accounts in an amount sufficient to satisfy all of INTL FCStone Financial’s current obligations to customers trading foreign futures and foreign options on foreign commodity exchanges or boards of trade, which are designated as secured customers’ accounts. See Additional Information of INTL FCStone Financial Related to Customer Segregated and Secured Funds further below for additional information regarding INTL FCStone Financial’s calculation of segregated and secured customer funds. The Company’s subsidiaries Sterne, Agee & Leach, Inc., Sterne Agee Clearing, Inc. and Sterne Agee Financial Services, Inc. are subject to the SEC Uniform Net Capital Rule 15c3-1 under the Securities Exchange Act of 1934. The Company’s subsidiary INTL FCStone Ltd is regulated by the Financial Conduct Authority (“FCA”), the regulator of the financial services industry in the United Kingdom, as a Financial Services Firm under part IV of the Financial Services and Markets Act 2000. The regulations impose regulatory capital, as well as conduct of business, governance, and other requirements. The conduct of business rules include those that govern the treatment of customer money and other assets which under certain circumstances for certain classes of customer must be segregated from the firm’s own assets. The Company’s subsidiary INTL FCStone Pty Ltd is regulated by the Australian Securities and Investment Commission and is subject to a net tangible asset capital requirement. INTL FCStone Pty Ltd is also regulated by New Zealand Clearing Limited, and is subject to a capital adequacy requirement. FCStone Commodity Services (Europe), Ltd. is domiciled in Ireland and subject to regulation by the Central Bank of Ireland, and is subject to a net capital requirement. INTL FCStone DTVM Ltda. (“INTL FCStone DTVM”) is a registered broker-dealer and regulated by the Brazilian Central Bank and Securities and Exchange Commission of Brazil, and is subject to a capital adequacy requirement. All subsidiaries of the Company are in compliance with all of their regulatory requirements as of September 30, 2016 , as follows: (in millions) As of September 30, 2016 Subsidiary Regulatory Authority Requirement Type Actual Minimum Requirement INTL FCStone Financial Inc. SEC and CFTC Net capital $ 140.8 $ 81.7 INTL FCStone Financial Inc. CFTC Segregated funds $ 2,177.9 $ 2,126.4 INTL FCStone Financial Inc. CFTC Secured funds $ 107.7 $ 91.3 Sterne Agee Clearing Inc. SEC Net capital $ 1.0 $ 0.1 Sterne, Agee & Leach, Inc. SEC Net capital $ 29.0 $ 2.0 Sterne Agee Financial Services, Inc. SEC Net capital $ 3.3 $ 0.3 INTL FCStone Ltd FCA (United Kingdom) Net capital $ 136.9 $ 84.9 INTL FCStone Ltd FCA (United Kingdom) Segregated funds $ 54.8 $ 49.5 INTL Netherlands BV FCA (United Kingdom) Net capital $ 136.1 $ 85.0 INTL FCStone DTVM Ltda. Brazilian Central Bank and Securities and Exchange Commission of Brazil Capital adequacy $ 2.5 $ 0.5 INTL Gainvest S.A. National Securities Commission ("CNV") Capital adequacy $ 7.7 $ 0.1 INTL Gainvest S.A. CNV Net capital $ 3.6 $ 0.1 INTL Capital S.A. General Inspector of Justice (Argentina) Net capital $ 15.3 $ 12.6 INTL CIBSA S.A. CNV Capital adequacy $ 7.1 $ 1.1 INTL CIBSA S.A. CNV Net capital $ 10.9 $ 0.6 Certain other non-U.S. subsidiaries of the Company are also subject to capital adequacy requirements promulgated by authorities of the countries in which they operate. As of September 30, 2016 , these subsidiaries were in compliance with their local capital adequacy requirements. Additional Information of INTL FCStone Financial Related to Customer Segregated and Secured Funds Pursuant to the requirements of the Commodity Exchange Act, funds deposited by customers of INTL FCStone Financial relating to futures and options on futures positions in regulated commodities must be carried in separate accounts which are designated as segregated customers’ accounts. Certain amounts in the accompanying table reflect reclassifications and eliminations required for regulatory filing. Funds deposited by customers and other assets, which have been segregated as belonging to the commodity customers as of September 30, 2016 and 2015 , are as follows: (in millions) September 30, 2016 September 30, 2015 Cash, at banks - segregated $ 383.6 $ 126.9 Securities representing investments of customers' funds, at banks 595.4 492.5 Securities held for customers in lieu of cash, at banks 1.8 0.9 Deposits with and receivables from: Exchange-clearing organizations, including securities, net of omnibus eliminations 1,173.9 1,237.8 Securities held for customers in lieu of cash 23.2 22.1 Total customer-segregated funds 2,177.9 1,880.2 Amount required to be segregated 2,126.4 1,830.9 Excess funds in segregation $ 51.5 $ 49.3 Funds deposited by customers and other assets, which are held in separate accounts for customers trading foreign futures and foreign options customers, as of September 30, 2016 and 2015 are as follows: (in millions) September 30, 2016 September 30, 2015 Cash - secured $ 70.5 $ 64.7 Securities — — Equities with registered futures commission merchants 3.6 2.6 Amounts held by clearing organizations of foreign boards of trade 6.7 — Amounts held by members of foreign boards of trade 26.9 18.3 Total customer-secured funds 107.7 85.6 Amount required to be secured 91.3 65.2 Excess secured funds $ 16.4 $ 20.4

Commodity and Other Repurchase

Commodity and Other Repurchase Agreements (Notes)	12 Months Ended
	Sep. 30, 2016
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, 2016 and 2015 was $1.5 million and $26.7 million , respectively. The obligations outstanding related to commodities sold under repurchase agreements that are recorded in ‘lenders under loans’ as of September 30, 2016 and 2015 were $43.5 million and $10.0 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, 2016 , on a settlement date basis, financial instruments owned of $47.2 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, 2016 , the Company pledged settlement date securities owned of $1,037.6 million and securities received under reverse repurchase agreements of $108.4 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, 2016 , 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, 2016 , was $607.3 million of which $504.4 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, 2016 , substantially all of the above collateral had been delivered against financial instruments sold, not yet purchased or repledged by the Company to obtain financing. Through its acquisition of Sterne Agee, as discussed in Note 18, in the normal course of business the Company has margin securities, securities borrowed and securities held on behalf of correspondent brokers, on terms which permit it to repledge the securities to others. At September 30, 2016, the Company had obtained and had available securities, on a settlement date basis, with a fair value of $148.4 million on such terms, of which $22.5 million have either been pledged or otherwise transferred to others in connection with the Company’s financing activities or to satisfy commitments under short sales.

Share-Based Compensation (Notes

Share-Based Compensation (Notes)	12 Months Ended
	Sep. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]	Share-Based Compensation Share-based compensation expense is included in ‘compensation and benefits’ in the consolidated income statements and totaled $5.1 million , $3.6 million and $4.3 million for the fiscal years ended September 30, 2016, 2015, and 2014 , respectively. Stock Option Plans The Company sponsors a stock option plan for its directors, officers, employees and consultants. The 2013 Stock Option Plan, which was approved by the Company’s Board of Directors and shareholders, authorizes the Company to issue stock options covering up to 1.0 million shares of the Company’s common stock. As of September 30, 2016 , there were 0.8 million shares authorized for future grant under this plan. Awards that expire or are canceled generally become available for issuance again under the plan. The Company settles stock option exercises with newly issued shares of common stock. Fair value is estimated at the grant date based on a Black-Scholes-Merton option-pricing model using the following weighted-average assumptions: Year Ended September 30, 2016 2015 2014 Expected stock price volatility 28 % 28 % 34 % Expected dividend yield — % — % — % Risk free interest rate 0.83 % 0.66 % 0.80 % Average expected life (in years) 3.06 3.22 2.88 Expected stock price volatility rates are primarily based on the historical volatility. The Company has not paid dividends in the past and does not currently expect to do so in the future. Risk free interest rates are based on the U.S. Treasury yield curve in effect at the time of grant for periods corresponding with the expected life of the option or award. The average expected life represents the estimated period of time that options or awards granted are expected to be outstanding, based on the Company’s historical share option exercise experience for similar option grants. The weighted average fair value of options issued during fiscal years ended September 30, 2016, 2015, and 2014 was $6.40 , $4.31 and $4.48 , respectively. The following is a summary of stock option activity for the year ended September 30, 2016 : Shares Available for Grant Number of Options Outstanding Weighted Average Exercise Price Weighted Average Grant Date Fair Value Weighted Average Remaining Term (in years) Aggregate Intrinsic Value ($ millions) Balances at September 30, 2015 828,665 1,297,984 $ 28.28 $ 12.37 4.24 $ 1.8 Granted (90,500 ) 90,500 $ 31.37 $ 6.40 Exercised (147,205 ) $ 18.52 $ 1.50 Forfeited 15,998 (16,498 ) $ 25.23 $ 5.28 Expired (8,960 ) $ 54.23 $ 20.04 Balances at September 30, 2016 754,163 1,215,821 $ 29.55 $ 12.88 3.80 $ 14.1 Exercisable at September 30, 2016 306,520 $ 40.58 $ 15.09 0.92 $ 2.2 The total compensation cost not yet recognized for non-vested awards of $5.3 million as of September 30, 2016 has a weighted-average period of 4.76 years over which the compensation expense is expected to be recognized. The total intrinsic value of options exercised during fiscal years 2016, 2015 and 2014 was $1.9 million , $3.6 million and $1.8 million , respectively. The options outstanding as of September 30, 2016 broken down by exercise price are as follows: Exercise Price Number of Options Outstanding Weighted Average Exercise Price Weighted Average Remaining Term $ — - $ 5.00 — n/a n/a $ 5.00 - $ 10.00 — n/a n/a $ 10.00 - $ 15.00 — n/a n/a $ 15.00 - $ 20.00 75,325 $ 18.77 1.00 $ 20.00 - $ 25.00 156,997 $ 22.07 1.73 $ 25.00 - $ 30.00 720,000 $ 25.91 5.38 $ 30.00 - $ 35.00 83,000 $ 31.37 3.28 $ 35.00 - $ 40.00 — n/a n/a $ 40.00 - $ 45.00 — n/a n/a $ 45.00 - $ 50.00 — n/a n/a $ 50.00 - $ 55.00 180,499 $ 54.23 0.68 1,215,821 $ 29.55 3.80 Restricted Stock Plan The Company sponsors a restricted stock plan for its directors, officers and employees. The Company’s 2012 restricted stock plan, which was approved by the Company’s Board of Directors and shareholders, authorizes up to 1.5 million shares to be issued. As of September 30, 2016 , 0.7 million shares were authorized for future grant under the restricted stock plan. Awards that expire or are canceled generally become available for issuance again under the plan. The Company utilizes newly issued shares of common stock to make restricted stock grants. The following is a summary of restricted stock activity through September 30, 2016 : Shares Available for Grant Number of Shares Outstanding Weighted Average Grant Date Fair Value Weighted Average Remaining Term (in years) Aggregate Intrinsic Value ($ millions) Balances at September 30, 2015 974,919 230,043 $ 20.10 2.17 $ 5.7 Granted (229,886 ) 229,886 $ 31.40 Vested (99,428 ) $ 19.84 Forfeited 2,749 (2,749 ) $ 21.89 Balances at September 30, 2016 747,782 357,752 $ 27.39 1.39 $ 13.9 The total compensation cost not yet recognized of $7.1 million as of September 30, 2016 has a weighted-average period of 1.39 years over which the compensation expense is expected to be recognized. Compensation expense is amortized on a straight-line basis over the vesting period. Restricted stock grants are included in the Company’s total issued and outstanding common shares.

Retirement Plans (Notes)

Retirement Plans (Notes)	12 Months Ended
	Sep. 30, 2016
Compensation and Retirement Disclosure [Abstract]
Pension and Other Postretirement Benefits Disclosure [Text Block]	Retirement Plans Defined Benefit Retirement Plans The Company has a frozen defined benefit pension plan (the “Plan”) and recognizes its funded status, measured as the difference between the fair value of the plan assets and the projected benefit obligation, in “accounts payable and other accrued liabilities” in the consolidated balance sheets. Plan assets, which are managed in a third-party trust, primarily consist of a diversified blend of approximately 70% debt securities and 30% equity investments and had a total fair value of $33.7 million and $30.2 million as of September 30, 2016 and 2015, respectively. All plan assets fall within Level 2 of the fair value hierarchy. The benefit obligation associated with the Plan will vary over time only as a result of changes in market interest rates, the life expectancy of the plan participants, and benefit payments, since the accrual of benefits was suspended when the Plan was frozen in 2006. The benefit obligation was $38.5 million and $37.1 million and the discount rate assumption used in the measurement of this obligation was 3.60% and 4.25% as of September 30, 2016 and 2015, respectively. The Company’s unfunded pension obligation was $4.8 million and $6.9 million as of September 30, 2016 and 2015, respectively. The net periodic benefit cost associated with the Plan was $0.2 million for the year ended September 30, 2016 and less than $0.1 million for the year ended September 30, 2015. The Company recognized a net periodic benefit of $0.1 million for the year ended September 30, 2014. The expected long-term return on plan assets assumption is 6.00% for 2016. The Company made contributions of $1.8 million and $2.2 million to the Plan in the years ended September 30, 2016 and 2015, respectively. The Company complies with minimum funding requirements. The estimated undiscounted future benefit payments are expected to be $3.0 million in 2017, $2.1 million in 2018, $2.1 million in 2019, $2.0 million in 2020, $1.9 million in 2021 and $9.3 million in 2022 through 2026. Defined Contribution Retirement Plans The Company offers participation in the INTL FCStone Inc. 401(k) Plan (“401(k) Plan”), a defined contribution plan providing retirement benefits, to all domestic employees who have reached 21 years of age, and provided four months of service to the Company. Employees may contribute from 1% to 80% of their annual compensation to the 401(k) Plan, limited to a maximum annual amount as set periodically by the Internal Revenue Service. The Company makes matching contributions to the 401(k) Plan in an amount equal to 62.5% of each participant’s eligible elective deferral contribution to the 401(k) Plan, up to 8% of employee compensation. Matching contributions vest, by participant, based on the following years of service schedule: less than two years – none, after two years – 33% , after three years – 66% , and after four years – 100% . U.K. based employees of INTL FCStone are eligible to participate in a defined contribution pension plan. The Company contributes double the employee’s contribution up to 10% of total base salary for this plan. For this plan, employees are 100% vested in both the employee and employer contributions at all times. For fiscal years ended September 30, 2016, 2015, and 2014 , the Company’s contribution to these defined contribution plans were $5.3 million , $5.1 million and $4.1 million , respectively.

Other Expenses (Notes)

Other Expenses (Notes)	12 Months Ended
	Sep. 30, 2016
Other Expenses [Abstract]
Other Expenses [Text Block]	Other Expenses Other expenses for the years ended September 30, 2016, 2015, and 2014 are comprised of the following: Year Ended September 30, (in millions) 2016 2015 2014 Contingent consideration, net (1) 0.4 1.8 (2.0 ) Insurance 2.1 1.7 1.6 Advertising, meetings and conferences 5.1 2.7 3.1 Non-trading hardware and software maintenance and software licensing 7.1 4.7 3.8 Office supplies and printing 1.1 1.2 1.1 Other clearing related expenses 1.3 1.1 1.2 Other non-income taxes 4.3 3.7 3.9 Other 8.0 6.6 5.7 Total other expenses $ 29.4 $ 23.5 $ 18.4 (1) Contingent consideration includes remeasurement of contingent liabilities related to business combinations accounted for in accordance with the provisions of the Business Combinations Topic of the ASC (see Note 3 ).

Income Taxes (Notes)

Income Taxes (Notes)	12 Months Ended
	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	Income Taxes Income tax expense (benefit) for the years ended September 30, 2016, 2015, and 2014 was allocated as follows: Year Ended September 30, (in millions) 2016 2015 2014 Income tax expense attributable to income from continuing operations $ 18.0 $ 22.4 $ 6.4 Income tax (benefit) expense attributable to loss from discontinued operations — — (0.2 ) Taxes allocated to stockholders’ equity, related to unrealized gains (losses) on available-for-sale securities — (0.4 ) 0.1 Taxes allocated to stockholders’ equity, related to pension liabilities 0.2 (0.8 ) (0.5 ) Taxes allocated to additional paid-in capital, related to share-based compensation (0.8 ) (0.5 ) 0.1 Total income tax expense $ 17.4 $ 20.7 $ 5.9 The components of the provision for income taxes attributable to income from continuing operations were as follows: Year Ended September 30, (in millions) 2016 2015 2014 Current taxes: U.S. federal $ 1.3 $ 0.8 $ 0.5 U.S. State and local 0.8 1.2 — International 16.8 15.4 11.6 Total current taxes 18.9 17.4 12.1 Deferred taxes (0.8 ) 5.0 (5.7 ) Income tax benefit attributable to interest income $ (0.1 ) $ — $ — Income tax expense $ 18.0 $ 22.4 $ 6.4 U.S. and international components of (loss) income from continuing operations, before income taxes, was as follows: Year Ended September 30, (in millions) 2016 2015 2014 U.S. $ 4.9 $ 14.5 $ (13.0 ) International 67.9 63.7 39.0 Income from continuing operations, before tax $ 72.8 $ 78.2 $ 26.0 Items accounting for the difference between income taxes computed at the federal statutory rate and the provision for income taxes were as follows: Year Ended September 30, 2016 2015 2014 Federal statutory rate effect of: 35.0 % 35.0 % 35.0 % U.S. State and local income taxes 1.3 % 1.8 % — % Foreign earnings taxed at lower rates (9.3 )% (10.1 )% (14.7 )% Change in foreign valuation allowance (0.3 )% (0.1 )% 1.9 % Change in state valuation allowance — % 0.6 % (0.2 )% Uncertain tax positions — % — % (0.5 )% U.S. permanent items 0.8 % 0.5 % 1.9 % Foreign permanent items 0.2 % 1.1 % 7.0 % U.S. bargain purchase gain (3.0 )% — % — % Other reconciling items 0.3 % (0.1 )% (5.7 )% Effective rate 25.0 % 28.7 % 24.7 % The components of deferred income tax assets and liabilities were as follows: (in millions) September 30, 2016 September 30, 2015 Deferred tax assets: Share-based compensation $ 4.3 $ 3.2 Pension liability 1.9 2.7 Deferred compensation 2.0 2.3 Foreign net operating loss carryforwards 2.0 2.3 U.S. State and local net operating loss carryforwards 4.9 4.3 U.S. federal net operating loss carryforwards 12.4 8.6 Intangible assets 8.3 4.6 Capital loss carryforwards — 0.2 Bad debt reserve 1.6 2.4 Tax Credit Carryforwards 1.4 1.0 Other compensation 3.3 1.9 Other 1.8 1.3 Total gross deferred tax assets 43.9 34.8 Less valuation allowance (3.6 ) (3.2 ) Deferred tax assets 40.3 31.6 Deferred income tax liabilities: Unrealized gain on securities 1.3 1.0 Prepaid expenses 1.9 1.1 Fixed assets 2.6 1.3 Deferred income tax liabilities 5.8 3.4 Deferred income taxes, net $ 34.5 $ 28.2 Deferred income tax balances reflect the effects of temporary differences between the carrying amounts of assets and liabilities and their tax bases and are stated at enacted tax rates expected to be in effect when taxes are actually paid or recovered. As of September 30, 2016 and 2015 , the Company has net operating loss carryforwards for U.S. federal, state, local, and foreign income tax purposes of $15.7 million and $12.0 million , net of valuation allowances, respectively, which are available to offset future taxable income in these jurisdictions. The U.S. federal net operating loss carryforward of $12.4 million begins to expire after September 2033. The state and local net operating loss carryforwards of $3.3 million , net of valuation allowance, begin to expire after September 2020. The Company has an Alternative Minimum Tax credit carryforward of $1.3 million , which has an indefinite life, and an R&D credit carryforward of $0.1 million that begins to expire after September 2031. The valuation allowance for deferred tax assets as of September 30, 2016 was $3.6 million . The net change in the total valuation allowance for the year ended September 30, 2016 was an increase of $0.4 million . The valuation allowances as of September 30, 2016 and 2015 were primarily related to U.S. state and local and foreign net operating loss carryforwards that, in the judgment of management, are not more likely than not to be realized. In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some or all of the deferred tax assets will not be realized. The Company incurred U.S. federal, state, and local taxable income/(losses) for the years ended September 30, 2016, 2015, and 2014 of $(9.7) million , $16.5 million , and $(18.4) million , respectively. There are no significant differences between actual levels of past taxable income and the results of continuing operations, before income taxes in these jurisdictions. When evaluating if U.S. federal, state, and local deferred taxes are realizable, the Company considered deferred tax liabilities of $4.5 million that are scheduled to reverse from 2017 to 2019 and $1.3 million of deferred tax liabilities associated with unrealized gains in securities which the Company could sell, if necessary. Furthermore, the Company considered its ability to implement business and tax planning strategies that would allow the remaining U.S. federal, state, and local deferred tax assets, net of valuation allowances, to be realized within 11 years. Based on the tax planning strategies that can be implemented, management believes that it is more likely than not that the Company will realize the tax benefit of the deferred tax assets, net of the existing valuation allowance, in the future. The total amount of undistributed earnings in the Company’s foreign subsidiaries, for income tax purposes, was $294.3 million and $227.2 million as of September 30, 2016 and 2015 , respectively. It is the Company’s current intention to reinvest undistributed earnings of its foreign subsidiaries in the foreign jurisdictions, resulting in the indefinite postponement of the remittance of those earnings. Accordingly, no provision has been made for foreign withholding taxes or U.S. federal income taxes which may become payable if undistributed earnings of foreign subsidiaries were paid as dividends to the Company. The Company recognizes the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by the taxing authority, based upon the technical merits of the position. The tax benefit recognized in the consolidated financial statements from such a position is measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: Year Ended September 30, (in millions) 2016 2015 2014 Balance, beginning of year $ — $ — $ 0.1 Gross increases for tax positions related to current year — — — Gross increases for tax positions related to prior years 0.1 — — Gross decreases for tax positions of prior years — — (0.1 ) Settlements — — — Lapse of statute of limitations — — — Balance, end of year $ 0.1 $ — $ — The Company has a minimal balance of uncertain tax benefits as of September 30, 2016 , that, if recognized, would affect the effective tax rate. While it is expected that the amount of unrecognized tax benefits will change in the next twelve months, the Company does not expect this change to have a material impact on the results of operations or the financial position of the Company. Accrued interest and penalties are included in the related tax liability line in the consolidated balance sheets. The Company had no accrued interest, net of federal benefit, and penalties included in the consolidated balance sheets as of September 30, 2016 and 2015 . The Company recognizes accrued interest and penalties related to income taxes as a component of income tax expense. The Company had no amount of interest, net of federal benefit, and penalties recognized as a component of income tax expense during the years ended September 30, 2016, 2015, and 2014 . The Company and its subsidiaries file income tax returns with the U.S. federal jurisdiction and various U.S. state and local and foreign jurisdictions. The Company has open tax years ranging from September 30, 2008 through September 30, 2016 with U.S. federal and state and local taxing authorities. In the U.K., the Company has open tax years ending September 30, 2015 to September 30, 2016. In Brazil, the Company has open tax years ranging from December 31, 2011 through December 31, 2015. In Argentina, the Company has open tax years ranging from September 30, 2009 to September 30, 2016. During the year ended September 30, 2016, the Company’s U.S. net operating loss carryback claim was reviewed by the Joint Committee of Taxation, and the Company received a full refund.

Acquisitions and Disposals (Not

Acquisitions and Disposals (Notes)	12 Months Ended
	Sep. 30, 2016
Business Combinations [Abstract]
Business Combination Disclosure [Text Block]	Acquisitions and Disposals Acquisition in Fiscal 2016 Sterne Agee Effective July 1, 2016 , the Company acquired all of the equity interests of Sterne Agee, LLC’s (a wholly-owned subsidiary of Stifel Financial Corp.) legacy independent brokerage and clearing businesses, Sterne Agee & Leach, Inc.; Sterne Agee Clearing, Inc.; Sterne Agee Financial Services, Inc. Effective August 1, 2016 , the Company acquired all of the equity interests of Sterne Agee, LLC’s legacy Registered Investment Advisor (“RIA”) business, Sterne Agee Asset Management, Inc. and Sterne Agee Investment Advisor Services, Inc. - collectively (“Sterne Agee”) for cash consideration. The acquisition-date fair value of the consideration transferred totaled $45.0 million . The preliminary purchase price allocation resulted in $24.9 million in cash, $151.6 million in receivables, $5.7 million in deferred tax assets, $4.8 million in other assets and $136.0 million in liabilities assumed. The fair value of identifiable assets acquired and liabilities assumed exceeded the fair value of the consideration transferred. Consequently, the Company reassessed the recognition and measurement of identifiable assets acquired and liabilities assumed and concluded that all acquired assets and assumed liabilities were recognized and that the valuation procedures and resulting measures were appropriate. As a result, the Company recognized a gain of $6.2 million , which is included in the line item ‘gain on acquisition’ in the consolidated income statement. The Company believes the transaction resulted in a gain primarily due to the Company’s ability to incorporate these business activities into its existing business structure, and its ability to utilize certain deferred tax assets and other assets while operating the business that may not have been likely to be realized by the seller. The allocation of the consideration to the fair value of the assets acquired and liabilities assumed is preliminary and subject to further adjustment as additional information is obtained. These allocations are subject to change within the measurement period (up to one year from the acquisition date) as final information is obtained. The businesses have been included within the Company’s Clearing and Execution Services Segment. The Company’s consolidated income statement for the year ended September 30, 2016 includes the post acquisition results of the Sterne Agee businesses, which were immaterial. The acquired businesses contributed net operating revenues of $8.6 million and net loss of $0.1 million to the Company for the period from July 1, 2016 to September 30, 2016. Acquisition in Fiscal 2015 The Company’s consolidated financial statements include the operating results of the acquired businesses from the dates of acquisition. G.X. Clarke & Co. Effective January 1, 2015, the Company acquired all of the partnership interests of G.X. Clarke & Co., an SEC registered institutional dealer in fixed income securities. G.X. Clarke was based in New Jersey, transacted in U.S. Treasury, U.S. government agency and agency mortgage-backed securities, and was a FINRA member with an institutional customer base consisting of asset managers, commercial bank trust and investment departments, broker-dealers, and insurance companies. The purchase price payable by the Company was equal to G.X. Clarke’s net tangible book value at closing of approximately $25.9 million plus a premium of $1.5 million , and up to an additional $1.5 million over the next three years, subject to the achievement of certain profitability thresholds. In conjunction with the acquisition, the name of G.X. Clarke was changed to INTL FCStone Partners L.P. The acquisition agreement includes the purchase of certain tangible assets and assumption of certain liabilities. For the acquisition, management made an initial fair value estimate of the assets acquired and liabilities assumed as of January 1, 2015. The Company believes that due to the short-term nature of many of the tangible assets acquired and liabilities assumed, that their carrying values, as included in the historical financial statements of G.X. Clarke, approximate their fair values. The Company finalized its purchase accounting estimates with the assistance of a third-party valuation expert. The portion of the purchase price representing the initial premium of $1.5 million and the contingent consideration of $0.1 million has been assigned to the customer base and software programs/platforms intangible assets (see Note 9 ). The Company assigned useful lives of 5 years for the customer base and software programs/platforms intangible assets. As part of the net cash paid, the Company and G.X. Clarke established two escrow accounts totaling $10.0 million , related to an Adjustment Escrow and Indemnity Escrow. The Adjustment Escrow, of $5.0 million , related to potential purchase price adjustment obligations was released, during year ended September 30, 2015, upon determination of the final tangible book value of net assets of G.X. Clarke. The Indemnity Escrow, of $5.0 million , relates to potential claims made by the Company for indemnification in accordance with the terms of the acquisition agreement and is to be released immediately following the twenty-four month anniversary of the closing date of the acquisition. The remaining escrow balance is included in ‘other assets’ in the consolidated balance sheet. In addition, as part of the net cash paid for the acquisition, the Company has deferred payment of $5.0 million , in accordance with the terms of the acquisition agreement. The deferred payment shall be equal to $5.0 million less the aggregate net loss, if any, incurred for the twelve full fiscal quarters commencing after the closing date. The deferred payment amount shall be due and payable shortly after the twelfth full fiscal quarter commencing after the closing date. The deferred payment is included in ‘accounts payable and other accrued liabilities’ in the consolidated balance sheet. As discussed above, the terms of the acquisition agreement include a contingent payment of an additional purchase price of up to $1.5 million , based on the performance of the acquired business. The contingent consideration, which in no event shall exceed $1.5 million , is expected to be paid in two payments. The first payment was made after the first four full fiscal quarters commencing after the closing date, and totaled $0.5 million , as the acquired business generated more than $5.0 million in after-tax net income over the first four full fiscal quarters after the closing date. The second and final payment is expected to occur after the twelfth full fiscal quarter commencing after the closing date. This payment is estimated to be $1.0 million , if the acquired business has generated accumulated after-tax net income of greater than $30.0 million over the twelve full fiscal quarters commencing after the closing date. Acquisition in Fiscal 2014 The Company’s consolidated financial statements include the operating results of the acquired businesses from the dates of acquisition. Forward Insight Commodities LLC In April 2014, the Company’s wholly owned subsidiary, FCStone Group, Inc. (“FCG”), acquired all of the outstanding member interests of Forward Insight Commodities, LLC (“FIC”). FIC was a brokerage firm focused on the structuring and execution of transactions in the energy derivative space. The consideration paid for the acquisition consisted of contingent payments based on the pre-tax earnings of the business for the twelve month period following the acquisition and was estimated to be $0.5 million as of the acquisition date. The purchase price for the acquisition was not material to the consolidated financial statements. The intangible assets recognized in this transaction of $0.5 million were assigned to the Clearing and Execution Services segment and were amortized over a 12 month useful life.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss) (Notes)	12 Months Ended
	Sep. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Abstract]
Comprehensive Income (Loss) Note [Text Block]	Accumulated Other Comprehensive Income (Loss) Comprehensive income consists of net income and other gains and losses affecting stockholders’ equity that, under U.S. GAAP, are excluded from net income. Other comprehensive income (loss) includes net actuarial losses from defined benefit pension plans and gains and losses on foreign currency translations. The following table summarizes the changes in accumulated other comprehensive income (loss) for the year ended September 30, 2016 . (in millions) Foreign Currency Translation Adjustment Pension Benefits Adjustment Accumulated Other Comprehensive Loss Balances as of September 30, 2015 $ (12.7 ) $ (4.8 ) $ (17.5 ) Other comprehensive income (loss), net of tax before reclassifications (7.4 ) (0.2 ) (7.6 ) Amounts reclassified from AOCI, net of tax — 0.5 0.5 Other comprehensive income (loss), net of tax (7.4 ) 0.3 (7.1 ) Balances as of September 30, 2016 $ (20.1 ) $ (4.5 ) $ (24.6 )

Discontinued Operations (Notes)

Discontinued Operations (Notes)	12 Months Ended
	Sep. 30, 2016
Discontinued Operations and Disposal Groups [Abstract]
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	Discontinued Operations Exit of Physical Base Metals Business During fiscal 2014, the Company completed its exit of the physical base metals business, that began in fiscal 2013, through the sale and orderly liquidation of then-current open positions. Under existing accounting guidance, before the implementation of ASU 2014-08, the Company reclassified the physical base metals activities in the financial statements as discontinued operations for all periods presented. The Company continues to operate the portion of its base metals business related to non-physical assets, conducted primarily through the London Metals Exchange. Summarized below are the components of the Company’s loss from discontinued operations for the years ended September 30, 2016, 2015, and 2014 : Year Ended September 30, (in millions) 2016 2015 2014 Revenues from discontinued operations $ — $ — $ 40.9 Cost of sales of physical commodities from discontinued operations — — 40.2 Operating revenues $ — $ — $ 0.7 Loss from discontinued operations before income taxes $ — $ — $ (0.5 ) Income tax benefit — — 0.2 Loss from discontinued operations, net of tax $ — $ — $ (0.3 )

Quarterly Financial Information

Quarterly Financial Information (Unaudited) (Notes)	12 Months Ended
	Sep. 30, 2016
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information [Text Block]	Quarterly Financial Information (Unaudited) The Company has set forth certain quarterly unaudited financial data for the past two years in the tables below: For the 2016 Fiscal Quarter Ended (in millions, except per share amounts) September 30 June 30 March 31 December 31 Total revenues $ 2,777.6 $ 4,868.5 $ 3,708.9 $ 3,399.9 Cost of sales of physical commodities 2,599.0 4,693.5 3,542.8 3,248.6 Operating revenues 178.6 175.0 166.1 151.3 Transaction-based clearing expenses 32.0 35.2 32.9 29.8 Introducing broker commissions 28.1 14.8 13.2 12.8 Interest expense 7.5 7.7 7.1 6.0 Net operating revenues 111.0 117.3 112.9 102.7 Compensation and other expenses 98.0 95.9 92.9 90.6 Gain on acquisition 6.2 — — — Income before tax 19.2 21.4 20.0 12.1 Income tax expense 2.4 6.8 5.5 3.3 Net income $ 16.8 $ 14.6 $ 14.5 $ 8.8 Net basic earnings per share $ 0.91 $ 0.79 $ 0.77 $ 0.47 Net diluted earnings per share $ 0.90 $ 0.78 $ 0.76 $ 0.46 For the 2015 Fiscal Quarter Ended (in millions, except per share amounts) September 30 June 30 March 31 December 31 Total revenues $ 2,628.4 $ 3,995.1 $ 14,442.0 $ 13,627.7 Cost of sales of physical commodities 2,449.7 3,843.5 14,285.5 13,490.2 Operating revenues 178.7 151.6 156.5 137.5 Transaction-based clearing expenses 31.3 30.2 31.8 29.4 Introducing broker commissions 15.1 13.1 12.3 12.2 Interest expense 5.0 4.9 4.5 2.7 Net operating revenues 127.3 103.4 107.9 93.2 Compensation and other expenses 98.1 86.2 89.8 79.6 Income before tax 29.2 17.2 18.1 13.6 Income tax expense 8.1 5.0 5.1 4.2 Net income $ 21.1 $ 12.2 $ 13.0 $ 9.4 Net basic earnings per share $ 1.12 $ 0.64 $ 0.68 $ 0.50 Net diluted earnings per share $ 1.09 $ 0.62 $ 0.67 $ 0.49 As discussed further in Note 22, during fiscal year 2015, the Company transitioned the portion of its precious metals business conducted through its unregulated domestic subsidiary, INTL Commodities Inc., to its U.K. based broker-dealer subsidiary, INTL FCStone Ltd. Prior to the transfer, INTL Commodities Inc.’s precious metals sales and costs of sales were recorded on a gross basis in accordance with the Revenue Recognition Topic of the ASC. Subsequent to the transfer, INTL FCStone Ltd’s precious metals sales and cost of sales are presented on a net basis and included as a component of ‘trading gains, net’ on the consolidated income statements, in accordance with U.S GAAP accounting requirements for broker-dealers. Precious metals sales and cost of sales for subsidiaries that are not broker-dealers continue to be recorded on a gross basis.

Segment and Geographic Informat

Segment and Geographic Information (Notes)	12 Months Ended
	Sep. 30, 2016
Segment Analysis [Abstract]
Segment Reporting Disclosure [Text Block]	Segment and Geographic Information The Company reports its operating segments based on services provided to customers. The Company’s business activities are managed as operating segments and organized into reportable segments as follows: • Commercial Hedging ( includes components Financial Agricultural (Ag) & Energy and LME Metals) • Global Payments • Securities (includes components Equity Market-Making, Debt Trading, Investment Banking, and Asset Management) • Physical Commodities (includes components Precious Metals and Physical Ag & Energy) • Clearing and Execution Services (includes components Exchange-traded Futures and Options, FX Prime Brokerage, Correspondent Clearing and Independent Wealth Management) Commercial Hedging The Company serves its commercial customers through its team of risk management consultants, providing a high-value-added service that we believe differentiates it from its competitors and maximizes the opportunity to retain customers. The Company’s risk management consulting services are designed to quantify and monitor commercial entities’ exposure to commodity and financial risk. Upon assessing this exposure the Company develops a plan to control and hedge these risks with post-trade reporting against specific ccustomer objectives. Customers are assisted in the execution of their hedging strategies through a wide range of products from listed exchange-traded futures and options, to basic OTC instruments that offer greater flexibility, to structured OTC products designed for customized solutions. The Company’s services span virtually all traded commodity markets, with the largest concentrations in agricultural and energy commodities (consisting primarily of grains, energy and renewable fuels, coffee, sugar, cotton, and food service) and base metals. The Company’s base metals business includes a position as a Category One ring dealing member of the LME, providing execution, clearing and advisory services in exchange-traded futures and OTC products. The Company also provides execution of foreign currency forwards and options and interest rate swaps as well as a wide range of structured product solutions to commercial customers who are seeking cost-effective hedging strategies. Generally, customers direct their own trading activity and the Company’s risk management consultants do not have discretionary authority to transact trades on behalf of customers. Global Payments The Company provides global payment solutions to banks and commercial businesses as well as charities and non-governmental organizations and government organizations. The Company offers payments services in over 175 countries and 140 currencies, which it believes is more than any other payments solution provider, and provides competitive and transparent pricing. Its proprietary FXecute global payments platform is integrated with a financial information exchange (“FIX”) protocol. This FIX protocol is an electronic communication method for the real-time exchange of information, and the Company believes it represents one of the first FIX offerings for cross-border payments in exotic currencies. FIX functionality allows customers to view real time market rates for various currencies, execute and manage orders in real-time, and view the status of their payments through the easy-to-use portal. Additionally, as a member of SWIFT (Society for Worldwide Interbank Financial Telecommunication), the Company is able to offer its services to large money center and global banks seeking more competitive international payments services. Through this single comprehensive platform and our commitment to customer service, the Company believes it is able to provide simple and fast execution, ensuring delivery of funds in any of these countries quickly through its global network of approximately 300 correspondent banks. In this business, the Company primarily acts as a principal in buying and selling foreign currencies on a spot basis. The Company derives revenue from the difference between the purchase and sale prices. The Company believes its customers value its ability to provide exchange rates that are significantly more competitive than those offered by large international banks, a competitive advantage that stems from its years of foreign exchange expertise focused on smaller, less liquid currencies. Securities The Company provides value-added solutions that facilitate cross-border trading and believes its customers value the Company’s ability to manage complex transactions, including foreign exchange, utilizing its local understanding of market convention, liquidity and settlement protocols around the world. The Company’s customers include U.S.-based regional and national broker-dealers and institutions investing or executing customer transactions in international markets and foreign institutions seeking access to the U.S. securities markets. The Company is one of the leading market makers in foreign securities, including unlisted ADRs, GDRs and foreign ordinary shares. The Company makes markets in over 3,600 ADRs, GDRs and foreign ordinary shares , of which over 2,000 trade in the OTC market. In addition, it will, on request, make prices in more than 10,000 unlisted foreign securities. The Company is a broker-dealer in Argentina where we are active in providing institutional executions in the local capital markets. The Company acts as an institutional dealer in fixed income securities, including U.S. Treasury, U.S. government agency, agency mortgage-backed and asset-backed securities to a customer base including asset managers, commercial bank trust and investment departments, broker-dealers and insurance companies. The Company also originates, structures and places debt instruments in the international and domestic capital markets. These instruments include complex asset-backed securities (primarily in Argentina) and domestic municipal securities. On occasion, the Company may invest its own capital in debt instruments before selling them. The Company also actively trades in a variety of international debt instruments and operates an asset management business in which it earns fees, commissions and other revenues for management of third party assets and investment gains or losses on its investments in funds and proprietary accounts managed either by its investment managers or by independent investment managers. Physical Commodities This segment consists of the Company’s physical Precious Metals trading and Physical Agricultural and Energy commodity businesses. In Precious Metals, the Company provides a full range of trading and hedging capabilities, including OTC products, to select producers, consumers, and investors. In the Company’s trading activities, it acts as a principal, committing its own capital to buy and sell precious metals on a spot and forward basis. The Company’s Physical Ag & Energy commodity business provides financing to commercial commodity-related companies against physical inventories, including grain, lumber, meats, energy products and renewable fuels. The Company uses sale and repurchase agreements to purchase commodities evidenced by warehouse receipts, subject to a simultaneous agreement to sell such commodities back to the original seller at a later date. Transactions where the sale and repurchase price are fixed upon execution are accounted for as product financing arrangements, and accordingly no commodity inventory, purchases or sales are recorded. Transactions where the repurchase price is not fixed upon execution do not meet all of the criteria to be accounted for as product financing arrangements and, thus, are recorded as commodity inventory, purchases, and sales. Additionally, the Company engages as a principal in physical purchase and sale transactions related to inputs to the renewable fuels and feed ingredient industries. On April 10, 2015 (the “transfer date”), the Company transitioned the portion of its Precious Metals business conducted through its unregulated domestic subsidiary, INTL Commodities Inc., to its U.K. based broker-dealer subsidiary, INTL FCStone Ltd. INTL FCStone Ltd is regulated by the Financial Conduct Authority (“FCA”), the regulator of the financial services industry in the U.K. Subsequent to the transfer, precious metals inventory held by INTL FCStone Ltd is measured at fair value, with changes in fair value included as a component of ‘trading gains, net’ on the consolidated income statement, in accordance with U.S. GAAP accounting requirements for broker-dealers. Precious metals inventory held by subsidiaries that are not broker-dealers continues to be valued at the lower of cost or market value. Prior to the transfer, INTL Commodities Inc.’s precious metals sales and costs of sales were recorded on a gross basis in accordance with the Revenue Recognition Topic of the ASC. Subsequent to the transfer, INTL FCStone Ltd’s precious metals sales and cost of sales are presented on a net basis and included as a component of ‘trading gains, net’ on the consolidated income statements, in accordance with U.S GAAP accounting requirements for broker-dealers. Precious metals sales and cost of sales for subsidiaries that are not broker-dealers continue to be recorded on a gross basis. The Company records its Physical Ag & Energy commodities revenues on a gross basis. Operating revenues and losses from its precious metals commodities derivatives activities are included in ‘trading gains, net’ in the consolidated income statements. Operating revenues and losses from its agricultural and energy commodities derivative activities are included in ‘cost of sales of physical commodities’ in the consolidated income statements. The agricultural commodity inventories are carried at net realizable value, which approximates fair value less disposal costs. The agricultural inventories have reliable, readily determinable and realizable market prices, have relatively insignificant costs of disposal and are available for immediate delivery. The Company generally mitigates the price risk associated with commodities held in inventory through the use of derivatives. The Company does not elect hedge accounting under U.S. GAAP in accounting for this price risk mitigation. Clearing and Execution Services (CES) The Company provides competitive and efficient clearing and execution in all major futures and securities exchanges globally as well as prime brokerage in all major foreign currency pairs and swap transactions. Through its platform, customer orders are accepted and directed to the appropriate exchange for execution. The Company then facilitates the clearing of customers’ transactions. Clearing involves the matching of customers’ trades with the exchange, the collection and management of customer margin deposits to support the transactions, and the accounting and reporting of the transactions to customers. As of September 30, 2016, the Company held $2.1 billion in required customer segregated assets, which it believes makes it the third largest independent futures commission merchant (“FCM”) in the United States not affiliated with a major financial institution or commodity intermediary, end-user or producer, as measured by required customer segregated assets. The Company seeks to leverage its capabilities and capacity by offering facilities management or outsourcing solutions to other FCM’s. Following the Company’s acquisition of the Sterne Agee correspondent securities clearing business, it is an independent full-service provider to introducing broker-dealers (“IBD’s”) of clearing, custody, research, syndicated and security-based lending products and services, including a proprietary technology platform which offers seamless connectivity to ensure a positive customer experience through the clearing and settlement process. Also as part of this transaction, the Company acquired Sterne Agee’s independent wealth management business which offers a comprehensive product suite to retail customers nationwide. As a result it is one of the leading mid-market clearer’s in the securities industry, clearing for 50 correspondent clearing customers and in aggregate over 120,000 underlying individual retail securities accounts with over $12 billion in assets under management (“AUM”) as of September 30, 2016. In addition, the Company believes it is one of the largest non-bank prime brokers and swap dealers in the world. Through this offering, it provides prime brokerage foreign exchange services to financial institutions and professional traders. The Company provides its customers with the full range of OTC products, including 24-hour a day execution of spot, forwards and options as well as non-deliverable forwards in both liquid and exotic currencies. The Company also operates a proprietary foreign exchange desk that arbitrages the exchange-traded foreign exchange markets with the cash markets. ******** The total revenues reported combine gross revenues for the physical commodities business and net revenues for all other businesses. In order to reflect the way that the Company’s management views the results, the tables below also reflect the segment contribution to ‘operating revenues’, which is shown on the face of the consolidated income statements and which is calculated by deducting physical commodities cost of sales from total revenues. Segment data includes the profitability measure of net contribution by segment. Net contribution is one of the key measures used by management to assess the performance of each segment and for decisions regarding the allocation of the Company’s resources. Net contribution is calculated as revenue less direct cost of sales, transaction-based clearing expenses, variable compensation, introducing broker commissions, and interest expense. Variable compensation paid to risk management consultants/traders generally represents a fixed percentage of an amount equal to revenues generated, and in some cases, revenues produced less transaction-based clearing charges, base salaries and an overhead allocation. Segment data also includes segment income which is calculated as net contribution less non-variable direct expenses of the segment. These non-variable direct expenses include trader base compensation and benefits, operational employee compensation and benefits, communication and data services, business development, professional fees, bad debts and other direct expenses. Inter-segment revenues, charges, receivables and payables are eliminated upon consolidation, except revenues and costs related to foreign currency transactions undertaken on an arm’s length basis by the foreign exchange trading business for the securities business. The foreign exchange trading business competes for this business as it does for any other business. If its rates are not competitive, the securities businesses buy or sell their foreign currency through other market counterparties. On a recurring basis, the Company sweeps excess cash from certain operating segments to a centralized corporate treasury function in exchange for an intercompany receivable asset. The intercompany receivable asset is eliminated during consolidation, and therefore this practice may impact reported total assets between segments. Information concerning operations in these segments of business is shown in accordance with the Segment Reporting Topic of the ASC as follows: Year Ended September 30, (in millions) 2016 2015 2014 Total revenues: Commercial Hedging $ 236.1 $ 262.4 $ 224.0 Global Payments 73.2 77.1 55.4 Securities 175.2 129.8 80.3 Physical Commodities 14,120.5 34,092.0 33,552.1 Clearing and Execution Services 151.1 123.4 113.7 Corporate unallocated (1.2 ) 8.5 (3.1 ) Total $ 14,754.9 $ 34,693.2 $ 34,022.4 Operating revenues (loss): Commercial Hedging $ 236.1 $ 262.4 $ 224.0 Global Payments 73.2 77.1 55.4 Securities 175.2 129.8 80.3 Physical Commodities 36.6 23.1 20.6 Clearing and Execution Services 151.1 123.4 113.7 Corporate unallocated (1.2 ) 8.5 (3.1 ) Total $ 671.0 $ 624.3 $ 490.9 Net operating revenues (loss): Commercial Hedging $ 188.2 $ 214.7 $ 180.5 Global Payments 65.3 68.5 48.2 Securities 121.9 88.6 54.6 Physical Commodities 31.5 21.2 17.9 Clearing and Execution Services 48.8 38.3 29.7 Corporate unallocated (11.8 ) 0.5 (8.9 ) Total $ 443.9 $ 431.8 $ 322.0 Net contribution: (Revenues less cost of sales, transaction-based clearing expenses, variable bonus compensation, introducing broker commissions and interest expense): Commercial Hedging $ 134.4 $ 151.7 $ 132.6 Global Payments 52.2 54.5 37.6 Securities 97.5 67.4 40.9 Physical Commodities 23.4 16.9 14.1 Clearing and Execution Services 39.5 30.1 24.0 Total $ 347.0 $ 320.6 $ 249.2 Segment income: (Net contribution less non-variable direct segment costs): Commercial Hedging $ 68.7 $ 85.6 $ 67.3 Global Payments 39.8 43.3 28.3 Securities 69.4 40.5 21.0 Physical Commodities 13.3 5.8 5.9 Clearing and Execution Services 14.8 12.9 6.3 Total $ 206.0 $ 188.1 $ 128.8 Reconciliation of segment income to income from continuing operations, before tax: Segment income $ 206.0 $ 188.1 $ 128.8 Costs not allocated to operating segments 133.3 110.0 102.8 Income from continuing operations, before tax $ 72.7 $ 78.1 $ 26.0 (in millions) As of September 30, 2016 As of September 30, 2015 As of September 30, 2014 Total assets: Commercial Hedging $ 1,637.5 $ 1,548.1 $ 1,400.9 Global Payments 191.4 207.3 51.9 Securities 2,130.7 1,861.0 235.5 Physical Commodities 258.0 190.9 116.8 Clearing and Execution Services 1,617.4 1,163.8 1,136.2 Corporate unallocated 116.3 98.9 98.4 Total $ 5,951.3 $ 5,070.0 $ 3,039.7 Information regarding revenues and operating revenues for the years ended September 30, 2016, 2015, and 2014 , and information regarding long-lived assets (defined as property, equipment, leasehold improvements and software) as of September 30, 2016, 2015, and 2014 in geographic areas were as follows: Year Ended September 30, (in millions) 2016 2015 2014 Total revenues: United States $ 817.1 $ 25,959.0 $ 19,055.3 Europe 463.5 121.2 86.0 South America 64.8 49.0 53.2 Asia 13,405.1 8,560.0 14,822.4 Other 4.4 4.0 5.5 Total $ 14,754.9 $ 34,693.2 $ 34,022.4 Operating revenues: United States $ 457.0 $ 424.3 $ 330.4 Europe 120.2 125.0 86.0 South America 64.8 49.0 53.2 Asia 24.6 21.9 15.8 Other 4.4 4.1 5.5 Total $ 671.0 $ 624.3 $ 490.9 (in millions) As of September 30, 2016 As of September 30, 2015 As of September 30, 2014 Long-lived assets, as defined: United States $ 23.3 $ 13.8 $ 8.5 Europe 4.8 4.0 5.0 South America 1.2 1.7 2.0 Asia 0.1 0.2 0.3 Other — — 0.1 Total $ 29.4 $ 19.7 $ 15.9

Condensed Parent Only Financial

Condensed Parent Only Financial Statements (Notes)	12 Months Ended
	Sep. 30, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Financial Information of Parent Company Only Disclosure [Text Block]	Schedule I INTL FCStone Inc. Condensed Balance Sheets Parent Company Only (in millions) September 30, September 30, ASSETS Cash and cash equivalents $ 1.3 $ 2.5 Deposits and receivables from broker-dealers, clearing organizations and counterparties 2.9 — Receivable from subsidiaries, net 3.6 0.4 Notes receivable, net 6.9 46.4 Income taxes receivable 14.0 24.3 Investment in subsidiaries (1) 316.3 286.0 Financial instruments owned, at fair value 1.3 3.0 Deferred income taxes, net 15.7 12.0 Property and equipment, net 12.7 9.2 Other assets 17.2 13.1 Total assets $ 391.9 $ 396.9 LIABILITIES AND EQUITY Liabilities: Accounts payable and other accrued liabilities $ 27.7 $ 29.3 Payable to customers 4.6 30.7 Payable to lenders under loans 139.3 31.6 Payable to subsidiaries, net 17.1 123.7 Senior unsecured notes 45.5 45.5 Financial instruments sold, not yet purchased, at fair value 35.9 — Total liabilities 270.1 260.8 Equity: INTL FCStone Inc. (Parent Company Only) stockholders’ equity: Preferred stock, $0.01 par value. Authorized 1,000,000 shares; no shares issued or outstanding — — Common stock, $0.01 par value. Authorized 30,000,000 shares; 20,557,175 issued and 18,435,218 outstanding at September 30, 2016 and 20,184,556 issued and 18,812,803 outstanding at September 30, 2015 0.2 0.2 Common stock in treasury, at cost - 2,121,957 shares at September 30, 2016 and 1,371,753 shares at September 30, 2015 (46.3 ) (26.8 ) Additional paid-in capital 249.4 240.8 Retained earnings (1) (81.5 ) (78.1 ) Total INTL FCStone Inc. (Parent Company Only) stockholders’ equity 121.8 136.1 Total liabilities and equity $ 391.9 $ 396.9 (1) Within the Condensed Balance Sheets and Condensed Statements of Operations of INTL FCStone Inc. - Parent Company Only, the Company has accounted for its investment in wholly owned subsidiaries using the cost method of accounting. Under this method, the Company’s share of the earnings or losses of such subsidiaries are not included in the Condensed Balance Sheet or Condensed Statements of Operations. If the accounting for its investment in wholly owned subsidiaries were presented under the equity method of accounting, investment in subsidiaries and retained earnings would each increase by $336.6 million as of September 30, 2016, respectively, and $278.5 million , as of September 30, 2015, respectively. Schedule I INTL FCStone Inc. Condensed Statements of Operations Parent Company Only Year Ended September 30, (in millions) 2016 2015 2014 Revenues: Management fees from affiliates $ 30.1 $ 26.6 $ 9.5 Trading gains, net 0.7 3.2 — Consulting fees 2.2 2.1 1.6 Interest income 1.8 4.6 4.3 Dividend income from subsidiaries (2) 31.0 6.0 — 65.8 42.5 15.4 Interest expense 13.4 12.7 10.6 Net revenues 52.4 29.8 4.8 Non-interest expenses: Compensation and benefits 52.8 43.5 29.8 Clearing and related expenses 1.7 1.2 0.3 Introducing broker commissions 0.6 0.5 0.3 Communication and data services 6.7 5.7 1.3 Occupancy and equipment rental 2.8 2.1 2.0 Professional fees 4.8 4.6 5.0 Travel and business development 1.7 1.4 1.1 Depreciation and amortization 2.5 1.8 1.8 Bad debts and impairments 0.2 1.6 0.1 Management services fees to affiliates 1.2 4.3 2.9 Other 11.7 10.2 3.5 Total non-interest expenses 86.7 76.9 48.1 Gain on acquisition 6.2 — — Loss from continuing operations, before tax (28.1 ) (47.1 ) (43.3 ) Income tax benefit 24.7 19.4 17.1 Net loss $ (3.4 ) $ (27.7 ) $ (26.2 ) (2) W ithin the Condensed Balance Sheets and Condensed Statements of Operations of INTL FCStone Inc. - Parent Company Only, the Company has accounted for its investment in wholly owned subsidiaries using the cost method of accounting. Under this method, the Company’s share of the earnings or losses of such subsidiaries are not included in the Condensed Balance Sheet or Condensed Statements of Operations. If the accounting for its investment in wholly owned subsidiaries were presented under the equity method of accounting, revenues would include income from investment in subsidiaries of $58.1 million , $83.4 million , and $45.5 million , for the years ended September 30, 2016, 2015, and 2014, respectively. Schedule I INTL FCStone Inc. Condensed Statements of Cash Flows Parent Company Only Year Ended September 30, (in millions) 2016 2015 2014 Cash flows from operating activities: Net loss $ (3.4 ) $ (27.7 ) $ (26.2 ) Adjustments to reconcile net loss to net cash (used in) provided by operating activities: Depreciation and amortization 2.5 1.8 1.8 Provision for impairments 0.2 1.6 0.1 Deferred income taxes (3.3 ) 4.6 (9.6 ) Amortization of debt issuance costs and debt discount 1.0 0.8 0.8 Amortization of share-based compensation expense 5.1 3.6 4.3 Gain on acquisition (6.2 ) — — Changes in operating assets and liabilities: Deposits and receivables from broker-dealers, clearing organizations, and counterparties (2.8 ) — — Receivables from subsidiaries, net (3.1 ) — — Due to/from subsidiaries (86.6 ) 33.2 84.6 Notes receivable, net 39.1 (7.8 ) (12.8 ) Income taxes receivable 10.3 (11.4 ) 4.6 Financial instruments owned, at fair value 1.7 (3.0 ) — Other assets 0.3 (3.9 ) (1.1 ) Accounts payable and other accrued liabilities 0.4 12.6 (1.1 ) Payable to customers (26.1 ) 4.9 7.1 Financial instruments sold, not yet purchased, at fair value 35.9 — (0.6 ) Net cash (used in) provided by operating activities (35.0 ) 9.3 51.9 Cash flows from investing activities: Capital contribution in affiliates (48.4 ) (22.4 ) (0.5 ) Capital withdrawals from affiliates — 7.8 — Purchase of property and equipment (5.5 ) (7.8 ) (1.8 ) Net cash used in investing activities (53.9 ) (22.4 ) (2.3 ) Cash flows from financing activities: Payable to lenders under loans 108.5 13.0 (40.0 ) Proceeds from note payable — 4.0 — Payments of notes payable (0.8 ) (0.4 ) — Payments related to earn-outs on acquisitions (2.9 ) (2.2 ) (1.1 ) Share repurchase (19.5 ) (4.7 ) (9.7 ) Debt issuance costs (1.9 ) (0.1 ) (0.2 ) Exercise of stock options 3.5 2.5 1.4 Income tax benefit on stock options and awards 0.8 0.5 (0.1 ) Net cash provided by (used in) financing activities 87.7 12.6 (49.7 ) Net (decrease) increase in cash and cash equivalents (1.2 ) (0.5 ) (0.1 ) Cash and cash equivalents at beginning of period 2.5 3.0 3.1 Cash and cash equivalents at end of period $ 1.3 $ 2.5 $ 3.0 Supplemental disclosure of cash flow information: Cash paid for interest $ 9.0 $ 11.9 $ 6.9 Income taxes (received) paid, net of cash refunds $ (33.8 ) $ (12.9 ) $ (5.3 ) Supplemental disclosure of non-cash investing and financing activities: Additional consideration payable related to acquisitions $ (0.4 ) $ 1.9 $ (3.0 )

Subsequent Events Subsequent Ev

Subsequent Events Subsequent Events (Notes)	12 Months Ended
	Sep. 30, 2016
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Subsequent Events Acquisition of ICAP’s EMEA Oils Broking Business In September 2016, the Company’s subsidiary, INTL FCStone Ltd, reached an agreement to acquire the London-based EMEA oils business of ICAP plc. INTL FCStone Ltd received approval from the U.K. Competition and Markets Authority, and acquisition is effective October 1, 2016. The business includes over 30 front office employees across the fuel, crude, middle distillates, futures and options desks with deep-rooted relationships with over 200 well known commercial and institutional customers throughout Europe, the Middle East and Africa. The terms of the agreement include a purchase price of $6.0 million as well as amounts payable to employees acquired based upon their continued employment. Redemption of Senior Notes On September 15, 2016, the Company instructed The Bank of New York Mellon, as trustee (the “Trustee”) under the Company’s Indenture dated as of July 22, 2013 for the Company’s 8.5% Senior Notes (the “Senior Notes”) to provide notice (the “Notice”) to the holders of the Senior Notes that the Company will redeem the aggregate outstanding $45.5 million principal amount of the Senior Notes in full. Pursuant to the terms of the Indenture, the Company will redeem the outstanding Senior Notes at a price equal to 100% of the principal amount redeemed plus accrued and unpaid interest to, but not including, the redemption date. The redemption date is October 15, 2016. The Notice was provided on September 15, 2016 to record holders of the Senior Notes by the Trustee.

Description of Business and S32

Description of Business and Significant Accounting Policies (Policies)	12 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Basis of Presentation, Policy [Policy Text Block]	Basis of Presentation The accompanying consolidated financial statements include the accounts of INTL FCStone Inc. and all other entities in which the Company has a controlling financial interest. All material intercompany transactions and balances have been eliminated in consolidation. Unless otherwise stated herein, all references to fiscal 2016 , fiscal 2015 , and fiscal 2014 refer to the Company’s fiscal years ended September 30. In the consolidated income statements, the total revenues reported combine gross revenues for the physical commodities business and net revenues for all other businesses. The subtotal ‘operating revenues’ in the consolidated income statements is calculated by deducting physical commodities cost of sales from total revenues. The subtotal ‘net operating revenues’ in the consolidated income statements is calculated as operating revenues less transaction based clearing expenses, introducing broker commissions and interest expense. Transaction-based clearing expenses represent variable expenses paid to executing brokers, exchanges, clearing organizations and banks in relation to our transactional volumes. Introducing broker commissions include commission paid to non-employee third parties that have introduced customers to the Company. Net operating revenues represent revenues available to pay variable compensation to risk management consultants and traders and direct non-variable expenses, as well as variable and non-variable expenses of operational and administrative employees.
Consolidation, Policy [Policy Text Block]	The accompanying consolidated financial statements include the accounts of INTL FCStone Inc. and all other entities in which the Company has a controlling financial interest. All material intercompany transactions and balances have been eliminated in consolidation.
Fiscal Period, Policy [Policy Text Block]	Unless otherwise stated herein, all references to fiscal 2016 , fiscal 2015 , and fiscal 2014 refer to the Company’s fiscal years ended September 30.
Use of Estimates, Policy [Policy Text Block]	Use of Estimates The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent liabilities as of the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. The most significant of these estimates and assumptions relate to fair value measurements for financial instruments and investments, revenue recognition, the provision for potential losses from bad debts, valuation of inventories, valuation of goodwill and intangible assets, self-insurance liabilities, incomes taxes and contingencies. These estimates are based on management’s best knowledge of current events and actions the Company may undertake in the future. The Company reviews all significant estimates affecting the financial statements on a recurring basis and records the effect of any necessary adjustments prior to their issuance. Although these and other estimates and assumptions are based on the best available information, actual results could be materially different from these estimates.
Foreign Currency Translations Policy [Policy Text Block]	Foreign Currency Translation Assets and liabilities recorded in foreign currencies are translated at the exchange rates prevailing on the balance sheet date. Revenue and expenses are translated at average rates of exchange prevailing during the period. Gains or losses on translation of the financial statements of a non-U.S. operation, when the functional currency is other than the U.S. dollar, are recorded in other comprehensive income (“OCI”), net of tax, a component of stockholders’ equity. Foreign currency remeasurement gains or losses on transactions denominated in nonfunctional currencies are included in ‘trading gains, net’ in the consolidated income statements.
Cash and Cash Equivalents, Unrestricted Cash and Cash Equivalents, Policy [Policy Text Block]	Cash and Cash Equivalents The Company considers cash held at banks and all highly liquid investments, including certificates of deposit, which may be withdrawn at any time at the discretion of the Company without penalty, to be cash and cash equivalents. Cash and cash equivalents consist of cash, foreign currency, money market funds and certificates of deposit not deposited with or pledged to exchange-clearing organizations, broker-dealers, clearing organizations or counterparties. The money market funds are valued at period-end at the net asset value provided by the fund’s administrator, which approximates fair value. Certificates of deposit are stated at cost plus accrued interest, which approximates fair value. The Company has an investment policy, which limits the maximum amount placed in any one fund and with any one institution in order to reduce credit risk. The Company does not believe that it is exposed to significant risk on cash and cash equivalents.
Cash, Securities and Other Assets Segregated, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]	Cash, Securities and Other Assets Segregated under Federal and other Regulations Pursuant to requirements of the Commodity Exchange Act in the U.S. and similarly in the United Kingdom (“U.K.”), pursuant to the Markets in Financial Instruments Implementing Directive 2006/73/EC underpinning the Client Asset or ‘CASS’ rules in the Financial Services Authority (“FSA”) handbook, funds deposited by customers relating to futures and options on futures contracts in regulated commodities must be carried in separate accounts which are designated as segregated customer accounts. The deposits in segregated customer accounts are not commingled with the funds of the Company. Under the FSA’s rules, certain categories of customers may choose to opt-out of segregation. As of September 30, 2016 and 2015 , cash, securities and other assets segregated under federal and other regulations consisted of cash held at banks and money market funds of approximately $515.2 million and $240.0 million , respectively, U.S. government securities and U.S. government agency obligations of approximately $595.5 million and $493.4 million , respectively, and commodities warehouse receipts of approximately $23.3 million and $22.1 million , respectively (see fair value measurements discussion in Note 3 ).
Deposits and Receivables from Exchange-Clearing Organizations, Broker-dealers, Clearing Organizations and Counterparties, and Payables to Broker-dealers, Clearing Organizations and Counterparties Disclosure [Text Block]	Deposits and Receivables from Exchange-Clearing Organizations, Broker-dealers, Clearing Organizations and Counterparties, and Payables to Broker-dealers, Clearing Organizations and Counterparties As required by the regulations of the U.S. Commodity Futures Trading Commission (“CFTC”) and the aforementioned FSA handbook, customer funds received to margin, guarantee, and/or secure commodity futures transactions are segregated and accounted for separately from the general assets of the Company. Deposits with exchange-clearing organizations, broker-dealers and counterparties pertain primarily to deposits made to satisfy margin requirements on customer and proprietary open futures and options on futures positions and to satisfy the requirements set by clearing exchanges for clearing membership. The Company also pledges margin deposit with various counterparties for OTC derivative contracts, and these deposits are also included in deposits and receivables from broker-dealers and counterparties. Deposits with and receivables from exchange-clearing organizations and broker-dealers and counterparties are reported gross, except where a right of offset exists. As of September 30, 2016 and 2015 , the Company had cash and cash equivalents on deposit with or pledged to exchange-clearing organizations, broker-dealers and counterparties of $0.9 billion . These balances also include securities pledged by the Company on behalf of customers and customer-owned securities that are pledged. It is the Company’s practice to include customer owned securities on its consolidated balance sheets, as the rights to those securities have been transferred to the Company under the terms of the futures trading agreement. Securities pledged include U.S. Treasury bills and instruments backed by U.S. government sponsored entities and government-sponsored enterprise backed mortgage-backed securities (“mortgage-backed securities”). Securities that are not customer-owned are adjusted to fair value with associated changes in unrealized gains or losses recorded through current period earnings. For customer owned securities, the change in fair value is offset against the payable to customers with no impact recognized in the consolidated income statements. The securities, primarily U.S. government obligations and mortgage-backed securities, held by INTL FCStone Financial, a subsidiary of the Company, as collateral or as margin have been deposited with exchange-clearing organizations, broker-dealers or other counterparties. The fair value of these securities was approximately $0.5 billion as of September 30, 2016 and 2015 . Management has considered guidance required by the Transfers and Servicing Topic of the ASC as it relates to securities pledged by customers to margin their accounts within the FCM Division of INTL FCStone Financial. Based on a review of the agreements with the customer, management believes the transferor surrenders control over those assets because: (a) the transferred assets have been isolated from the transferor—put presumptively beyond the reach of the transferor and its creditors, even in bankruptcy or other receivership, (b) each transferee has the right to pledge or exchange the assets (or beneficial interests) it received, and no condition both constrains the transferee (or holder) from taking advantage of its right to pledge or exchange and provides more than a trivial benefit to the transferor and (c) the transferor does not maintain effective control over the transferred assets through either (1) an agreement that both entitles and obligates the transferor to repurchase or redeem them before their maturity or (2) the ability to unilaterally cause the holder to return specific assets, other than through a cleanup call. Under this guidance, the Company reflects the customer collateral assets and corresponding liabilities in the Company’s consolidated balance sheets as of September 30, 2016 and 2015 . In addition to margin, deposits with exchange-clearing organizations include guaranty deposits. The guaranty deposits are held by the clearing organization for use in potential default situations by one or more members of the clearing organization. The guaranty deposits may be applied to the Company’s obligations to the clearing organization, or to the clearing organization’s obligations to other clearing members or third parties. The Company maintains customer omnibus and proprietary accounts with other counterparties, and the equity balances in those accounts along with any margin cash or securities deposited with the carrying broker are included in deposits and receivables from broker-dealers and counterparties. Receivables from and payables to exchange-clearing organizations are also comprised of amounts due from or due to exchange-clearing organizations for daily variation settlements on open futures and options on futures positions. The variation settlements due from or due to exchange-clearing organizations are paid in cash on the following business day. Deposits and receivables from broker-dealers, clearing organizations and counterparties, and payables to broker-dealers, clearing organizations and counterparties also include amounts related to the value of customers cross-currency payment transactions related to the Global Payments segment. These amounts arise due to a clearing period before the funds are received and payments are made, which usually is one to two business days. Deposits and receivables with exchange-clearing organizations also includes the unrealized gains and losses associated with the customers’ options on futures contracts. See discussion in the Financial Instruments and Derivatives section below for additional information on the treatment of derivative contracts. For customer owned derivative contracts, the fair value is offset against the payable to customers with no impact recognized on the consolidated income statements.
Receivable from and Payable to Customers, Policy [Policy Text Block]	Receivable from and Payable to Customers Receivable from customers, net of the allowance for doubtful accounts, include the total of net deficits in individual exchange-traded and OTC trading accounts carried by the Company. Customer deficits arise from realized and unrealized trading losses on futures, options on futures, swaps and forwards and amounts due on cash and margin transactions. Customer deficit accounts are reported gross of customer accounts that contain net credit or positive balances, except where a right of offset exists. Net deficits in individual exchange-traded and OTC trading accounts include both secured and unsecured deficit balances due from customers as of the balance sheet date. Secured deficit amounts are backed by U.S. Treasury bills and notes and commodity warehouse receipts. These U.S Treasury bills and notes and commodity warehouse receipts are not netted against the secured deficit amounts, as the conditions for right of setoff have not been met. Payable to customers represent the total of customer accounts with credit or positive balances. Customer accounts are used primarily in connection with commodity transactions and include gains and losses on open commodity trades as well as securities and other deposits made as required by the Company, the exchange-clearing organizations or other clearing organizations. Customer accounts with credit or positive balances are reported gross of customer deficit accounts, except where a right of offset exists. Receivables from and payables to customers also include amounts related to the value of customers cross-currency payment transactions related to the Global Payments segment. These amounts arise due to a clearing period before the funds are received and payments are made, which usually is one to two business days. The future collectability of the receivable from customers can be impacted by the Company’s collection efforts, the financial stability of its customers, and the general economic climate in which it operates. The Company evaluates accounts that it believes may become uncollectible on a specific identification basis, through reviewing daily margin deficit reports, the historical daily aging of the receivables, and by monitoring the financial strength of its customers. The Company may unilaterally close customer trading positions in certain circumstances. In addition, to evaluate customer margining and collateral requirements, customer positions are stress tested regularly and monitored for excessive concentration levels relative to the overall market size. The Company generally charges off an outstanding receivable balance when all economically sensible means of recovery have been exhausted. That determination considers information such as the occurrence of significant changes in the customer’s financial position such that the customer can no longer pay the obligation, or that the proceeds from collateral will not be sufficient to pay the balance.
Notes Receivable, Policy [Policy Text Block]	Notes Receivable The Company originates short-term notes receivable from customers with the outstanding balances typically being insured 90% to 98% by a third party, including accrued interest, subject to applicable deductible amounts. The Company may sell the insured portion of the notes through non-recourse participation agreements with other third parties. See discussion of notes receivable related to commodity repurchase agreements below. Accrual of commodity financing income on any note is discontinued when, in the opinion of management, there is reasonable doubt as to the timely collectability of interest or principal. Nonaccrual notes are returned to an accrual status when, in the opinion of management, the financial position of the borrower indicates there is no longer any reasonable doubt as to the timely payment of principal and interest. The Company records a charge against earnings for notes receivable losses when management believes that collectability of the principal is unlikely.
Physcial Commodities Inventory, Policy [Policy Text Block]	Physical Commodities Inventory Inventories of certain agricultural commodities are carried at net realizable value, which approximates fair value less disposal costs. The agricultural commodities inventories have reliable, readily determinable and realizable market prices, have relatively predictable and insignificant costs of disposal and are available for immediate delivery. Changes in the fair values of these agricultural commodities inventories are included as a component of ‘cost of physical commodities sold’ in the consolidated income statements. Inventories of precious metals, except as described below, are stated at the lower of cost or market (“LCM”), using the weighted-average price and first-in first-out costing method. Prior to the transfer of the Company’s precious metals business (see following discussion), precious metals inventory held by INTL Commodities Inc. was valued at LCM under the provisions of the Inventory Topic of the Accounting Standards Codification (“ASC”), using the weighted-average price and first-in first-out costing method. Subsequent to the transfer, precious metals inventory held by INTL FCStone Ltd is measured at fair value, with changes in fair value included as a component of ‘trading gains, net’ in the consolidated income statements. Change in Precious Metals Accounting The Company engages in trading activities in a variety of physical commodities, including actively trading precious metals whereby the Company provides a full range of trading and hedging capabilities, including OTC products, to select producers, consumers, and investors. In the Company’s precious metals trading activities, it acts as a principal, committing its own capital to buy and sell precious metals on a spot and forward basis. On April 10, 2015 (the “transfer date”), the Company transitioned the portion of its precious metals business conducted through its unregulated domestic subsidiary, INTL Commodities Inc., to its United Kingdom based broker-dealer subsidiary, INTL FCStone Ltd INTL FCStone Ltd is regulated by the Financial Conduct Authority (“FCA”), the regulator of the financial services industry in the United Kingdom. In anticipation of the transfer of the precious metals business, INTL Commodities Inc. liquidated all of its precious metals inventory as of the transfer date. Subsequent to the transfer, precious metals inventory held by INTL FCStone Ltd is measured at fair value, with changes in fair value included as a component of ‘trading gains, net’ in the consolidated income statement, in accordance with U.S. GAAP accounting requirements for broker-dealers. Precious metals inventory held by subsidiaries that are not broker-dealers continues to be valued at the lower of cost or market value.
Property and Equipment, Policy [Policy Text Block]	Property and Equipment Property and equipment is stated at cost, net of accumulated depreciation and amortization and depreciated using the straight-line method over the estimated useful lives of the assets. Leasehold improvements are amortized on a straight-line basis over the estimated useful life of the improvement or the term of the lease, whichever is shorter. Certain costs of software developed or obtained for internal use are capitalized and amortized over the estimated useful life of the software. Expenditures for maintenance, repairs, and minor replacements are charged against earnings, as incurred. Expenditures that increase the value or productive capacity of assets are capitalized. When property and equipment are retired, sold, or otherwise disposed of, the asset’s carrying amount and related accumulated depreciation are removed from the accounts and any gain or loss is included in earnings.
Goodwill and Intangible Assets, Policy [Policy Text Block]	Goodwill and Identifiable Intangible Assets Goodwill is the cost of acquired companies in excess of the fair value of identifiable net assets at acquisition date. In accordance with the Intangibles – Goodwill and Other Topic of the ASC, goodwill is tested for impairment on an annual basis at the fiscal year-end, and between annual tests if indicators of potential impairment exist, using a fair-value-based approach. No impairment of goodwill has been identified during any of the periods presented. Identifiable intangible assets subject to amortization are amortized using the straight-line method over their estimated period of benefit, ranging from two to twenty years. Identifiable intangible assets are tested for impairment whenever events or changes in circumstances suggest that an asset’s or asset group’s carrying value may not be fully recoverable in accordance with the Intangibles – Goodwill and Other Topic of the ASC. Residual value is presumed to be zero. Identifiable intangible assets not subject to amortization are reviewed at each reporting period to re-evaluate if the intangible asset’s useful life remains indefinite. Additionally, intangible assets not subject to amortization are tested annually for impairment at the fiscal year-end, and between annual tests if indicators of potential impairment exist, using a fair-value-based approach.
Financial Instruments and Derivatives, Policy [Policy Text Block]	Financial Instruments and Derivatives Financial instruments owned and sold, not yet purchased, at fair value consist of financial instruments carried at fair value or amounts that approximate fair value, with related unrealized changes in gains or losses recognized in earnings. The fair value of a financial instrument is the amount at which the instrument could be exchanged in a current transaction between willing parties, other than in a forced or liquidation sale. The Company accounts for its securities pledged on behalf of customers and proprietary securities as trading securities in accordance with U.S. GAAP accounting requirements for broker-dealers. Investment in managed funds, at fair value represents investments in funds managed by the Company’s fund managers. The investments are valued at period-end at the net asset value provided by the fund’s administrator. Commodities warehouse receipts are valued at the cash price, or the nearby futures prices in the absence of a cash price, for the commodity based on published market quotes. For commodities warehouse receipts, the change in fair value is offset against the payable to customers with no impact on the consolidated income statements. The Company utilizes derivative instruments to manage exposures to foreign currency, commodity price and interest rate risks for the Company and its customers. The Company’s objectives for holding derivatives include reducing, eliminating, and efficiently managing the economic impact of these exposures as effectively as possible. Derivative instruments are recognized as either assets or liabilities and are measured at fair value. The accounting for changes in the fair value of a derivative depends on the intended use of the derivative and the resulting designation. For a derivative instrument designated as a cash flow hedge, the effective portion of the derivative’s gain or loss is initially recorded in OCI, net of tax, and is subsequently recognized in earnings when the hedged exposure affects earnings. The ineffective portion of the gain or loss is recognized in earnings. Gains and losses from changes in fair values of derivatives that are not designated as cash flow hedges for accounting purposes are recognized in earnings. The Company’s derivative contracts consist of exchange-traded and OTC derivatives. Fair values of exchange-traded derivatives are generally determined from quoted market prices. OTC derivatives are valued using valuation models. The valuation models used to derive the fair values of OTC derivatives require inputs including contractual terms, market prices, yield curves and measurements of volatility. The Company uses similar models to value similar instruments. Where possible, the Company verifies the values produced by pricing models by comparing them to market transactions. Inputs may involve judgment where market prices are not readily available. The Company does not elect hedge accounting under the Derivatives and Hedging Topic of the ASC in accounting for derivatives used as economic hedges on its commodities. The Company’s derivative contracts also include forward purchase and sale contracts for physical delivery of the agricultural commodities in a future period. Contracts to purchase agricultural commodities generally relate to the current or future crop year. Contracts for the sale of agricultural commodities generally do not extend beyond one year. Forward purchase and sale contracts are valued at market prices when available or other market quotes adjusted for differences, primarily in transportation, between the exchange-traded market and local markets where the terms of the contracts are based. Changes in the fair value of agricultural commodity inventories held for sale, forward purchase and sale contracts and exchange-traded futures and options contracts are recognized as a component of cost of sales of physical commodities. The Company provides clearing and execution of exchange-traded futures and options on futures for middle-market intermediaries, end-users, producers of commodities and the institutional and professional trader market segments. The Company has a subsidiary that is a registered broker-dealer/FCM, clearing on various exchanges. A primary source of revenues for the Company’s broker-dealer/FCM are commissions and clearing fees derived from executing and clearing orders for commodity futures contracts and options on futures on behalf of its customers. The Company also brokers foreign exchange forwards, options and cash, or spot, transactions between customers and external counterparties. A portion of the contracts are arranged on an offsetting basis, limiting the Company’s risk to performance of the two offsetting parties. The offsetting nature of the contracts eliminates the effects of market fluctuations on the Company’s operating results. Due to the Company’s role as a principal participating in both sides of these contracts, the amounts are presented gross on the consolidated balance sheets at their respective fair values, net of offsetting assets and liabilities. The Company holds proprietary positions in its foreign exchange line of business. On a limited basis, the Company’s foreign exchange trade desk will accept a customer transaction and will offset that transaction with a similar but not identical position with a counterparty. These unmatched transactions are intended to be short-term in nature and are often conducted to facilitate the most effective transaction for the Company’s customer. These spot and forward contracts are accounted for as free-standing derivatives and reported in the consolidated balance sheets at their fair values. The Company does not seek hedge accounting treatment for these derivatives, and accordingly, the changes in fair value during the period are recorded in the consolidated income statements in ‘trading gains, net’ (see Note 4 ). In applying the guidance in the Balance Sheet-Offsetting Topic of the ASC, the Company’s accounting policy is such that open contracts with the same customer are netted at the account level, in accordance with netting arrangements in place with each party, as applicable and rights to reclaim cash collateral or obligations to return cash collateral are netted against fair value amounts recognized for derivative instruments with the same customer in accordance with the master netting arrangements in place with each customer. The Company may lease commodities to or from customers or counterparties, or advance commodities to customers on an unpriced basis, receiving payment when they become priced. These are valued at fair value utilizing the fair value option based on guidance in the Financial Instruments Topic of the ASC. As permitted by the fair value option election, the entire instrument is recorded at fair value in the consolidated balance sheets as a component of ‘financial instruments owned and sold, not yet purchased’. Due to the short term nature of the instruments, the balance of the agreements is not materially different than the recorded fair value. The corresponding change in fair value of the instrument is recognized in the consolidated income statements as a component of ‘trading gains, net’ for the fiscal years ended September 30, 2016, 2015, and 2014 . The Company does elect to value all of their commodities lease agreements at fair value using the fair value option. See fair value measurements in Note 3 .
Exchange Memberships and Stock, Policy [Policy Text Block]	Exchange Memberships and Stock The Company is required to hold certain exchange membership seats and exchange firm common stock and pledge them for clearing purposes, in order to provide the Company the right to process trades directly with the various exchanges. Exchange memberships include seats on the Chicago Board of Trade (“CBOT”), the Minneapolis Grain Exchange, the New York Mercantile Exchange (“NYMEX”), the Commodity Exchange, Inc. (“COMEX”) Division of the New York Mercantile Exchange, Mercado de Valores de Buenos Aires S.A. (“MERVAL”), the Chicago Mercantile Exchange (“CME”) Growth and Emerging Markets, InterContinental Exchange, Inc. (“ICE”) Futures US, ICE Europe Ltd and London Metal Exchange (“LME”), and the Deposit Trust and Clearing Corporation (“DTCC”). Exchange firm common stock include shares of CME Group, Inc., ICE and LME. Exchange memberships and firm common stocks pledged for clearing purposes are recorded at cost and are included in ‘other assets’ on the consolidated balance sheets. Equity investments in exchange firm common stock not pledged for clearing purposes are classified as trading securities and recorded at fair value, with unrealized gains and losses recorded as a component of “trading gains, net” on the consolidated income statements. Equity investments in exchange firm common stock not pledged for clearing purposes are included in ‘financial instruments owned’ on the consolidated balance sheets. The cost basis for exchange memberships and firm common stock pledged for clearing purposes was $12.1 million and $9.9 million as of September 30, 2016 and 2015 , respectively. The fair value of exchange memberships and firm common stock pledged for clearing purposes was $9.1 million and $7.6 million as of September 30, 2016 and 2015 , respectively. The fair value of exchange firm common stock is determined by quoted market prices, and the fair value of exchange memberships is determined by recent sale transactions. The Company monitors the fair value of exchange membership seats and firm common stock on a quarterly basis, and does not consider any current unrealized losses on individual exchange memberships to be anything other than a temporary impairment.
Commodity Repurchase and Other Repurchase Agreements Policy [Policy Text Block]	Commodity and Other Repurchase Agreements and Collateralized Transactions
Business Combinations and Contingent Consideration Policy [Policy Text Block]	Business Combinations Acquisitions are accounted for as business combinations in accordance with the provisions of the Business Combinations Topic of the ASC. Under this accounting guidance most of the assets and liabilities acquired and assumed are measured at fair value as of the acquisition date. Certain contingent liabilities acquired require remeasurement at fair value in each subsequent reporting period. Noncontrolling interests are initially measured at fair value and classified as a separate component of equity. Acquisition related costs, such as fees for attorneys, accountants, and investment bankers, are expensed as incurred and are not capitalized as part of the purchase price. For all acquisitions, regardless of the consummation date, deferred tax assets, valuation allowances, and uncertain tax position adjustments occurring after the measurement period are recorded as a component of income, rather than adjusted through goodwill. Determining the fair value of certain assets and liabilities acquired is subjective in nature and often involves the use of significant estimates and assumptions. Estimating the fair value of the assets and liabilities acquired requires significant judgment. Contingent Consideration The Company estimates and records the acquisition date estimated fair value of contingent consideration as part of purchase price consideration for acquisitions. Additionally, each reporting period, the Company estimates changes in the fair value of contingent consideration, and any change in fair value is recognized in the consolidated income statement. An increase in the earn-out expected to be paid will result in a charge to operations in the period that the anticipated fair value of contingent consideration increases, while a decrease in the earn-out expected to be paid will result in a credit to operations in the period that the anticipated fair value of contingent consideration decreases. The estimate of the fair value of contingent consideration requires subjective assumptions to be made of future operating results, discount rates, and probabilities assigned to various potential operating result scenarios. Future revisions to these assumptions could materially change the estimate of the fair value of contingent consideration and, therefore, materially affect the Company’s future financial results.
Additional Paid-In Capital, Policy [Policy Text Block]	Additional Paid-In Capital The Company’s additional paid-in capital (“APIC”) consists of stockholder contributions that are in excess of par value of common stock. Included in APIC are amounts related to the exercise of stock options, share-based compensation and shares held in escrow. In September 2010, the Company acquired certain assets of Provident Group (“Provident”). The purchase price for the assets and services of the sellers was $5.0 million . Subsequent to closing, the individual sellers placed the entire purchase price into an escrow account and the funds were used to purchase outstanding shares of the Company on the open market. There were 214,325 shares purchased and placed into escrow as a result of this agreement. The entire purchase price was recorded as a reduction in additional paid in capital as shares held in escrow for business combinations. The shares held in escrow for business combinations were to be released to the individual sellers, over a five year period from the date of closing based on net profits, in accordance with the provisions of the acquisition agreement. At September 30, 2015, the end of the five year period, the terms of the agreement were not met and 204,271 shares were forfeited to the Company and recorded as treasury stock. In accordance with the acquisition agreement, there were no shares earned or released during the year ended September 30, 2015, while 10,054 shares were earned and subsequently released to the sellers prior to fiscal 2015.
Revenue Recognition, Policy [Policy Text Block]	Revenue Recognition Sales of physical commodities revenue are recognized when persuasive evidence of an arrangement exists, delivery has occurred, the fee is fixed or determinable, and collectability is reasonably assured. The Company reports its physical commodities revenues, except as described below, on a gross basis, with the corresponding cost of sales shown separately, in accordance with the guidelines provided in the Revenue Recognition Topic of the ASC. Change in Precious Metals Accounting Prior to the transfer, INTL Commodities Inc. precious metals sales and costs of sales were recorded on a gross basis in accordance with the Revenue Recognition Topic of the ASC. Subsequent to the transfer, INTL FCStone Ltd precious metals sales and cost of sales are presented on a net basis and included as a component of ‘trading gains, net’ in the consolidated income statements, in accordance with U.S GAAP accounting requirements for broker-dealers. Precious metals sales and cost of sales for subsidiaries that are not broker-dealers continue to be recorded on a gross basis. The change has no effect on the Company’s operating revenues, income from continuing operations, or net income. Management has historically assessed the performance of the physical commodities businesses on an operating revenue basis, and continues to do so. Trading gains, net include brokerage fees and margins generated from OTC derivative trades executed with customers and other counterparties and are recognized when trades are executed. Trading gains, net also include activities where the Company acts as principal in the purchase and sale of individual securities, currencies, commodities or derivative instruments with customers. These transactions may be offset simultaneously with another customer or counterparty, offset with similar but not identical positions on an exchange, made from inventory, or may be aggregated with other purchases to provide liquidity intraday, for a number of days, or in some cases, particularly the base metals business, even longer periods (during which fair value may fluctuate). In addition, trading gains, net includes activities from the Company’s operations of a proprietary foreign exchange desk which arbitrages the futures and cash markets (see additional discussion in the Financial Instruments and Derivatives policy note for revenue recognition on proprietary trading activities). Net dealer inventory and investment gains are recognized on a trade-date basis and include realized gains or losses and changes in unrealized gains or losses on investments at fair value. Dividend income and dividend expense, on short equity positions, are recognized net, in ‘trading gain, net’ on the ex-dividend date. Commissions on futures contracts are recognized on a half-turn basis in two equal parts. The first half is recognized when the contract is opened and the second half is recognized when the transaction is closed. Commissions on options on futures contracts are generally recognized on a half-turn basis, except that full commissions are recognized on options expected to expire without being exercised or offset. Commissions and fees are charged at various rates based on the type of account, the products traded, and the method of trade. Clearing and transaction fees are charged to customers on a per exchange contract basis based on the trade date. Such fees are for clearing customers’ exchange trades and include fees charged to the Company by the various futures exchanges. See discussion of transaction-based clearing expenses below. Consulting and management fees include risk management consulting fees which are billed and recognized as revenue on a monthly basis when risk management services are provided. Such agreements are generally for one year periods, but are cancelable by either party upon providing thirty days written notice to the other party and the amounts are not variable based on customer trading activities. Asset management fees are recognized as they are earned based on fees due at each period-end date. These include performance fees based on the amount that is due under the formula for exceeding performance targets as of the period-end date. Fee income for structuring and arrangement of debt transactions and management and investment advisory income is recorded when the services related to the underlying transactions are provided and success fees are recorded when complete, as determined under the terms of the assignment or engagement. Interest income, generated primarily from investments and customer inventory financing, is recognized on an accrual basis. Interest from investments is generated from securities purchased using customer funds deposited with the Company to satisfy margin requirements, net of interest returned to customers, and from securities acquired through internally-generated company funds. Interest also includes unrealized gains and losses on securities owned and those deposited with other parties. Revenue generally is recognized net of any taxes collected from customers and subsequently remitted to governmental authorities.
Cost of of Sales Physical Commodities, Policy [Policy Text Block]	Cost of Sales of Physical Commodities Cost of sales of physical commodities include finished commodity or raw material and processing costs along with operating costs relating to the receipt, storage and delivery of the physical commodities.
Compensation and Benefits, Policy [Policy Text Block]	Compensation and Benefits Compensation and benefits consists primarily of salaries, incentive compensation, variable compensation, including commissions, related payroll taxes and employee benefits. The Company classifies employees as either risk management consultants / traders, operational or administrative personnel, which includes the executive officers. Variable compensation paid to risk management consultants and traders generally represents a fixed percentage of revenues generated, and in some cases, revenues produced less direct costs and an overhead allocation. The Company accrues commission expense on a trade date basis.
Share-based Compensation Policy [Policy Text Block]	Share-Based Compensation The Company accounts for share-based compensation in accordance with the guidance of the Compensation-Stock Compensation Topic of the ASC. The cost of employee services received in exchange for a share-based award is generally measured based on the grant-date fair value of the award. Share-based employee awards that require future service are amortized over the relevant service period. Expected forfeitures are included in determining share-based employee compensation expense. For option awards granted, compensation cost is recognized on a straight-line basis over the vesting period for the entire award.
Transaction-Based Clearing Expenses, Policy [Policy Text Block]	Transaction-Based Clearing Expenses Clearing fees and related expenses include primarily variable expenses for clearing and settlement services, including fees the Company pays to executing brokers, exchanges, clearing organizations and banks. These fees are based on transaction volume, and recorded as expense on the trade date. Clearing fees are passed on to customers and are presented gross in the consolidated statements of income under the Revenue Recognition Topic of the ASC, as the Company acts as a principal for these transactions.
Introducing Broker Commissions, Policy [Policy Text Block]	Introducing Broker Commissions Introducing broker commissions include commissions paid to non-employee third parties that have introduced customers to the Company. Introducing brokers are individuals or organizations that maintain relationships with customers and accept futures and options orders from those customers. The Company directly provides all account, transaction and margining services to introducing brokers, including accepting money, securities and property from the customers. The commissions are determined and settled monthly.
Income Tax, Policy [Policy Text Block]	Income Taxes Income tax expense includes U.S. federal, state and local and foreign income taxes. Certain items of income and expense are not reported in tax returns and financial statements in the same year. The tax effect of such temporary differences is reported as deferred income taxes. Tax provisions are computed in accordance with the Income Taxes Topic of the ASC.
Comprehensive Income, Policy [Policy Text Block]	Comprehensive Income Comprehensive income consists of net income and other gains and losses affecting stockholders’ equity that, under U.S. GAAP, are excluded from net income. Other comprehensive income (loss) includes net actuarial losses from defined benefit pension plans and gains and losses on foreign currency translations.
Noncontrolling Interest and Variable Interest Entity, Policy [Policy Text Block]	Noncontrolling Interest and Variable Interest Entities In accordance with the Consolidation Topic of the ASC, the Company consolidates any variable interest entities for which it is the primary beneficiary, as defined. The Company applies the equity method of accounting when the Company does not have a controlling interest in an entity, but exerts significant influence over the entity.
Preferred Stock [Text Block]	Preferred Stock The Company is authorized to issue one million shares of preferred stock, par value of $0.01 per share, in one or more classes or series to be established by the Company’s board of directors. As of September 30, 2016 and 2015 , no preferred shares were outstanding and the Company’s board of directors had not yet established any class or series of shares.
Recent Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements I n August 2016, the FASB issued Accounting Standards Update (“ASU”) 2016-15, Classification of Certain Cash Receipts and Cash Payments (Topic 230), which addresses eight classification issues related to the statement of cash flows. This ASU is effective for public business entities for annual and interim periods in fiscal years beginning after December 15, 2017. For all other entities, the ASU is effective for annual periods in fiscal years beginning after December 15, 2018, and interim periods in fiscal years beginning after December 15, 2019. Entities should apply this ASU using a retrospective transition method to each period presented. Early adoption is permitted, including adoption in an interim period. The Company expects to adopt this guidance starting with the first quarter of fiscal year 2019. The Company is currently evaluating the impact the new guidance will have on its statement of cash flows. In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments, which significantly changes the ways entities recognize credit losses on financial instruments. The guidance is effective for public business entities for annual and interim periods in fiscal years beginning after December 15, 2019, with early adoption permitted in annual and interim periods in fiscal years beginning after December 15, 2018. The Company expects to adopt this guidance starting with the first quarter of fiscal year 2021. The guidance introduces a new credit reserving model known as the Current Expected Credit Loss (“CECL”) model, which is based on expected losses, and differs significantly from the incurred loss approach used today. The CECL model requires measurement of expected credit losses not only based on historical experience and current conditions, but also by including reasonable and supportable forecasts incorporating forward-looking information and will likely result in earlier recognition of credit reserves. The Company is currently evaluating the impact the new guidance will have on its financial position, results of operations and cash flows. In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606). ASU 2014-09 completes the joint effort by the FASB and International Accounting Standards Board (IASB) to improve financial reporting by creating common revenue recognition guidance for GAAP and International Financial Reporting Standards (IFRS). In March 2016, the FASB issued ASU 2016-08, “Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net).” ASU 2016-08 clarifies the implementation guidance on principal versus agent considerations. In April 2016, the FASB issued ASU 2016-10, “Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing.” ASU 2016-10 clarifies the implementation guidance on identifying performance obligations. These ASUs apply to all companies that enter into contracts with customers to transfer goods or services. These ASUs are effective for public entities for interim and annual reporting periods beginning after December 15, 2017. Early adoption is permitted only as of annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period. The Company expects to adopt this guidance starting with the first quarter of fiscal year 2019. Entities have the choice to apply these ASUs either retrospectively to each reporting period presented or by recognizing the cumulative effect of applying these standards at the date of initial application and not adjusting comparative information. The Company is currently evaluating the requirements of these standards and has not yet determined the impact on its financial position, results of operations and cash flows. In March 2016, the FASB issued ASU 2016-09, Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. ASU 2016-09 simplifies the accounting for share-based payment award transactions including: income tax consequences, classification of awards as either equity or liabilities and classification on the statement of cash flows. ASU 2016-09 is effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. Early adoption is permitted. The Company expects to adopt this guidance starting with the first quarter of fiscal year 2018. The Company is currently evaluating the requirements of ASU 2016-09 and has not yet determined the impact on its financial position, results of operations and cash flows. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which supersedes ASC 840, Leases. This ASU is based on the principle that entities should recognize assets and liabilities arising from leases. The ASU does not significantly change the lessees’ recognition, measurement and presentation of expenses and cash flows from the previous accounting standard. The ASU’s primary change is the requirement for entities to recognize a lease liability for payments and a right of use asset representing the right to use the leased asset during the term on operating lease arrangements. Lessees are permitted to make an accounting policy election to not recognize the asset and liability for leases with a term of twelve months or less. Lessors’ accounting under the ASC is largely unchanged from the previous accounting standard. In addition, the ASU expands the disclosure requirements of lease arrangements. Lessees and lessors will use a modified retrospective transition approach, which includes a number of practical expedients. This guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The Company expects to adopt this guidance starting with the first quarter of fiscal year 2020. The Company has not yet determined the impact on its financial position, results of operations and cash flows. In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments--Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. ASU No. 2016-01 addresses the recognition, measurement, presentation and disclosure of financial assets and liabilities. The guidance primarily affects the accounting for equity investments, financial liabilities under the fair value option and the presentation and disclosure requirements for financial instruments. In addition, the guidance clarifies the valuation allowance assessment when recognizing deferred tax assets resulting from unrealized losses on available-for-sale debt securities. This guidance is effective for the Company in the first quarter of fiscal 2019, and early adoption is not permitted, with certain exceptions. The amendments are required to be applied by means of a cumulative-effect adjustment on the balance sheet as of the beginning of the fiscal year of adoption. The Company is currently assessing the impact, if any, the guidance may have upon adoption. In April 2015, the FASB issued ASU No. 2015-03, Interest – Imputation of Interest (Subtopic 835-30). ASU 2015-03 requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability. In June 2015, the FASB issued ASU 2015-15 as an amendment to this guidance to address the absence of authoritative guidance for debt issuance costs related to line-of-credit arrangements. The SEC staff stated that they would not object to an entity deferring and presenting debt issuance costs as an asset and subsequently amortizing the deferred debt issuance costs ratably over the term of the line-of-credit arrangement, regardless of whether there are any outstanding borrowings on the line-of-credit arrangement. The ASU is effective for public entities for annual periods beginning after December 15, 2015, and interim periods within those annual reporting periods. Early adoption is permitted for financial statements that have not been previously issued. The guidance will be applied on a retrospective basis. The Company expects to adopt this guidance starting with the first quarter of fiscal year 2017. The adoption of this standard is not expected to have a material impact on the financial statements.

Earnings per Share (Tables)

Earnings per Share (Tables)	12 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Schedule of Calculation of Numerator and Denominator in Earnings Per Share [Table Text Block]	The following is a reconciliation of the numerator and denominator of the diluted net income per share computations for the periods presented below. Year Ended September 30, (in millions, except share amounts) 2016 2015 2014 Numerator: Income from continuing operations $ 54.7 $ 55.7 $ 19.6 Less: Allocation to participating securities (1.0 ) (1.3 ) (0.5 ) Income from continuing operations allocated to common stockholders $ 53.7 $ 54.4 $ 19.1 Loss from discontinued operations $ — $ — $ (0.3 ) Less: Allocation to participating securities — — — Loss from discontinued operations allocated to common stockholders $ — $ — $ (0.3 ) Diluted net income $ 54.7 $ 55.7 $ 19.3 Less: Allocation to participating securities (1.0 ) (1.3 ) (0.5 ) Diluted net income allocated to common stockholders $ 53.7 $ 54.4 $ 18.8 Denominator: Weighted average number of: Common shares outstanding 18,410,561 18,525,374 18,528,302 Dilutive potential common shares outstanding: Share-based awards 214,811 406,861 604,000 Diluted shares outstanding 18,625,372 18,932,235 19,132,302

Assets and Liabilities, at Fa34

Assets and Liabilities, at Fair Value (Tables)	12 Months Ended
	Sep. 30, 2016
Assets and Liabilities, at Fair Value [Abstract]
Fair Value, Assets Measured on Recurring Basis [Table Text Block]	The following tables set forth the Company’s financial and nonfinancial assets and liabilities accounted for at fair value, on a recurring basis, as of September 30, 2016 and September 30, 2015 by level in the fair value hierarchy. There were no assets or liabilities that were measured at fair value on a nonrecurring basis as of September 30, 2016 and 2015 . September 30, 2016 (in millions) Level 1 Level 2 Level 3 Netting and Total Assets: Unrestricted cash equivalents - certificates of deposits $ 7.1 $ — $ — $ — $ 7.1 Commodities warehouse receipts 23.3 — — — 23.3 U.S. government obligations — 595.5 — — 595.5 Securities and other assets segregated under federal and other regulations 23.3 595.5 — — 618.8 Money market funds 512.7 — — — 512.7 U.S. government obligations — 472.1 — — 472.1 Derivatives 2,149.9 — — (2,266.2 ) (116.3 ) Deposits and receivables from exchange-clearing organizations 2,662.6 472.1 — (2,266.2 ) 868.5 “To be announced” (TBA) and forward settling securities — 0.3 — — 0.3 Derivatives — 8.0 — (23.5 ) (15.5 ) Deposits and receivables from broker-dealers, clearing organizations and counterparties — 8.3 — (23.5 ) (15.2 ) Common and preferred stock and ADRs 34.6 1.7 0.2 — 36.5 Exchangeable foreign ordinary equities and ADRs 25.2 0.5 — — 25.7 Corporate and municipal bonds 36.9 0.9 3.0 — 40.8 U.S. government obligations — 514.9 — — 514.9 Foreign government obligations — 14.6 — — 14.6 Mortgage-backed securities — 747.5 — — 747.5 Derivatives 206.9 1,350.8 — (1,363.8 ) 193.9 Commodities leases — 137.2 — (129.1 ) 8.1 Commodities warehouse receipts 8.9 — — — 8.9 Exchange firm common stock 6.4 — — — 6.4 Mutual funds and other 8.8 — — — 8.8 Financial instruments owned 327.7 2,768.1 3.2 (1,492.9 ) 1,606.1 Physical commodities inventory 71.2 — — — 71.2 Total assets at fair value $ 3,091.9 $ 3,844.0 $ 3.2 $ (3,782.6 ) $ 3,156.5 Liabilities: Accounts payable and other accrued liabilities - contingent liabilities $ — $ — $ 0.8 $ — $ 0.8 TBA and forward settling securities — 2.6 — 0.9 3.5 Derivatives 1,961.7 97.5 — (2,059.2 ) — Payables to broker-dealers, clearing organizations and counterparties 1,961.7 100.1 — (2,058.3 ) 3.5 Common and preferred stock and ADRs 23.5 0.4 — — 23.9 Exchangeable foreign ordinary equities and ADRs 25.3 0.5 — — 25.8 Corporate and municipal bonds 6.9 — — — 6.9 U.S. government obligations — 509.8 — — 509.8 Foreign government obligations — — — — — Mortgage-backed securities — — — — — Derivatives 199.4 1,319.3 — (1,307.8 ) 210.9 Commodities leases — 207.8 — (145.7 ) 62.1 Financial instruments sold, not yet purchased 255.1 2,037.8 — (1,453.5 ) 839.4 Total liabilities at fair value $ 2,216.8 $ 2,137.9 $ 0.8 $ (3,511.8 ) $ 843.7 (1) Represents cash collateral and the impact of netting across the levels of the fair value hierarchy. Netting among positions classified within the same level are included in that level. September 30, 2015 (in millions) Level 1 Level 2 Level 3 Netting and Total Assets: Unrestricted cash equivalents - certificates of deposits $ 1.3 $ — $ — $ — $ 1.3 Commodities warehouse receipts 22.1 — — — 22.1 U.S. government obligations — 493.4 — — 493.4 Securities and other assets segregated under federal and other regulations 22.1 493.4 — — 515.5 Money market funds 431.8 — — — 431.8 U.S. government obligations — 501.4 — — 501.4 Derivatives 3,615.9 — — (3,539.7 ) 76.2 Deposits and receivables from exchange-clearing organizations 4,047.7 501.4 — (3,539.7 ) 1,009.4 TBA and forward settling securities — 1.2 — (1.0 ) 0.2 Derivatives 0.1 537.9 — (591.1 ) (53.1 ) Deposits and receivables from broker-dealers, clearing organizations and counterparties - derivatives 0.1 539.1 — (592.1 ) (52.9 ) Common and preferred stock and ADRs 23.7 1.9 0.5 — 26.1 Exchangeable foreign ordinary equities and ADRs 82.9 6.6 — — 89.5 Corporate and municipal bonds 26.1 2.0 3.2 — 31.3 U.S. government obligations — 513.4 — — 513.4 Foreign government obligations — 12.1 — — 12.1 Mortgage-backed securities — 699.5 — — 699.5 Derivatives 278.5 1,702.0 — (1,949.9 ) 30.6 Commodities leases — 64.6 — (57.0 ) 7.6 Commodities warehouse receipts 2.8 — — — 2.8 Exchange firm common stock 5.6 — — — 5.6 Mutual funds and other 3.4 — — — 3.4 Financial instruments owned 423.0 3,002.1 3.7 (2,006.9 ) 1,421.9 Physical commodities inventory 15.2 — — — 15.2 Total assets at fair value $ 4,509.4 $ 4,536.0 $ 3.7 $ (6,138.7 ) $ 2,910.4 Liabilities: Accounts payable and other accrued liabilities - contingent liabilities $ — $ — $ 3.3 $ — $ 3.3 TBA and forward settling securities — 2.6 — (1.0 ) 1.6 Derivatives 3,491.3 528.7 — (4,020.0 ) — Payable to broker-dealers, clearing organizations and counterparties - derivatives 3,491.3 531.3 — (4,021.0 ) 1.6 Common and preferred stock and ADRs 18.0 0.6 — — 18.6 Exchangeable foreign ordinary equities and ADRs 89.0 1.0 — — 90.0 U.S. government obligations — 341.0 — — 341.0 Foreign government obligations — 6.4 — — 6.4 Mortgage-backed securities — 2.8 — — 2.8 Derivatives 264.0 1,723.5 — (1,933.4 ) 54.1 Commodities leases — 99.1 — (43.7 ) 55.4 Financial instruments sold, not yet purchased 371.0 2,174.4 — (1,977.1 ) 568.3 Total liabilities at fair value $ 3,862.3 $ 2,705.7 $ 3.3 $ (5,998.1 ) $ 573.2 (1) Represents cash collateral and the impact of netting across the levels of the fair value hierarchy. Netting among positions classified within the same level are included in that level.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	The Company’s financial assets at fair value classified within level 3 of the fair value hierarchy as of September 30, 2016 and 2015 are summarized below: (in millions) September 30, 2016 September 30, 2015 Total level 3 assets $ 3.2 $ 3.7 Level 3 assets for which the Company bears economic exposure $ 3.2 $ 3.7 Total assets $ 5,951.3 $ 5,070.0 Total financial assets at fair value $ 3,156.5 $ 2,910.4 Total level 3 assets as a percentage of total assets 0.1 % 0.1 % Level 3 assets for which the Company bears economic exposure as a percentage of total assets 0.1 % 0.1 % Total level 3 assets as a percentage of total financial assets at fair value 0.1 % 0.1 % The following tables set forth a summary of changes in the fair value of the Company’s level 3 financial assets and liabilities during the fiscal years ended September 30, 2016 and 2015 , including a summary of unrealized gains (losses) during the fiscal year ended on the Company’s level 3 financial assets and liabilities still held as of September 30, 2016 . Level 3 Financial Assets and Financial Liabilities (in millions) Balances at Realized gains Unrealized Purchases/ Settlements Transfers in Balances at Assets: Common and preferred stock and ADRs $ 0.5 $ — $ (0.3 ) $ — $ — $ — $ 0.2 Corporate and municipal bonds 3.2 — (0.2 ) — — — 3.0 $ 3.7 $ — $ (0.5 ) $ — $ — $ — $ 3.2 (in millions) Balances at Realized gains Remeasurement Acquisitions Settlements Transfers in Balances at Liabilities: Contingent liabilities $ 3.3 $ — $ 0.4 $ — $ (2.9 ) $ — $ 0.8 Level 3 Financial Assets and Financial Liabilities (in millions) Balances at Realized gains Unrealized Purchases/ Settlements Transfers in Balances at Assets: Common and preferred stock and ADRs $ 0.7 $ — $ (0.2 ) $ — $ — $ — $ 0.5 Corporate and municipal bonds 3.6 — (0.4 ) — — — 3.2 $ 4.3 $ — $ (0.6 ) $ — $ — $ — $ 3.7 (in millions) Balances at Realized gains Remeasurement Acquisitions Settlements Transfers in Balances at Liabilities: Contingent liabilities $ 5.5 $ — $ 1.8 $ 0.1 $ (4.1 ) $ — $ 3.3

Financial Instruments with Of35

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk (Tables)	12 Months Ended
	Sep. 30, 2016
Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk [Abstract]
Schedule of Derivative Instruments Included in Trading Activities [Table Text Block]	As of September 30, 2016 , these transactions are summarized as follows (in millions): Gain / (Loss) Notional Amounts Unrealized gain on TBA securities purchased within payables to broker-dealers, clearing organizations and counterparties and related notional amounts (1) $ 0.8 $ 289.8 Unrealized loss on TBA securities purchased within payables to broker-dealers, clearing organizations and counterparties and related notional amounts (1) $ (0.8 ) $ 485.5 Unrealized gain on TBA securities sold within payables to broker-dealers, clearing organizations and counterparties and related notional amounts (1) $ 1.3 $ (702.3 ) Unrealized loss on TBA securities sold within payables to broker-dealers, clearing organizations and counterparties and related notional amounts (1) $ (1.7 ) $ (754.3 ) Unrealized gain on forward settling securities purchased within receivables from broker-dealers, clearing organizations and counterparties and related notional amounts $ 0.1 $ 607.9 Unrealized gain on forward settling securities sold within receivables from broker-dealers, clearing organizations and counterparties and related notional amounts $ 0.2 $ (470.4 ) (1) The notional amounts of these instruments reflect the extent of the Company’s involvement in TBA securities and do not represent risk of loss due to counterparty non-performance.
Schedule of Derivative Instruments [Table Text Block]	Listed below are the fair values of the Company’s derivative assets and liabilities as of September 30, 2016 and 2015 . Assets represent net unrealized gains and liabilities represent net unrealized losses. September 30, 2016 September 30, 2015 (in millions) Assets (1) Liabilities (1) Assets (1) Liabilities (1) Derivative contracts not accounted for as hedges: Exchange-traded commodity derivatives $ 2,022.1 $ 1,920.5 $ 3,443.6 $ 3,313.8 OTC commodity derivatives 1,217.0 1,188.9 1,621.2 1,650.7 Exchange-traded foreign exchange derivatives 12.2 7.5 27.8 20.6 OTC foreign exchange derivatives 346.5 290.2 892.2 865.4 Exchange-traded interest rate derivatives 78.7 120.5 126.8 136.0 Equity index derivatives 39.1 50.3 22.8 21.0 TBA and forward settling securities 0.3 2.6 1.2 2.6 Gross fair value of derivative contracts 3,715.9 3,580.5 6,135.6 6,010.1 Impact of netting and collateral (3,653.5 ) (3,366.1 ) (6,081.7 ) (5,954.4 ) Total fair value included in ‘Deposits and receivables from exchange-clearing organizations’ $ (116.3 ) $ 76.2 Total fair value included in ‘Deposits and receivables from broker-dealers, clearing organizations and counterparties’ $ (15.2 ) $ (52.9 ) Total fair value included in ‘Financial instruments owned, at fair value’ $ 193.9 $ 30.6 Total fair value included in ‘Payables to broker-dealers, clearing organizations and counterparties $ 3.5 $ 1.6 Fair value included in ‘Financial instruments sold, not yet purchased, at fair value’ $ 210.9 $ 54.1 (1) As of September 30, 2016 and 2015 , the Company’s derivative contract volume for open positions was approximately 4.0 million and 4.1 million contracts, respectively.
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance [Table Text Block]	The following table sets forth the Company’s net gains (losses) related to derivative financial instruments for the fiscal years ended September 30, 2016, 2015, and 2014 , in accordance with the Derivatives and Hedging Topic of the ASC. The net gains (losses) set forth below are included in ‘trading gains, net’ in the consolidated income statements. Year Ended September 30, (in millions) 2016 2015 2014 Commodities $ 41.8 $ 78.6 $ 65.7 Foreign exchange 9.7 7.5 7.5 Interest rate and equity 0.8 3.2 — TBA and forward settling securities (14.4 ) (5.1 ) — Net gains from derivative contracts $ 37.9 $ 84.2 $ 73.2

Receivables from customers, n36

Receivables from customers, net and notes receivable, net (Tables)	12 Months Ended
	Sep. 30, 2016
Receivables from customers and notes receivable, net [Abstract]
Allowance for Doubtful Accounts and Notes Receivables [Table Text Block]	Activity in the allowance for doubtful accounts and notes for the years ended September 30, 2016, 2015, and 2014 was as follows: (in millions) 2016 2015 2014 Balance, beginning of year $ 11.2 $ 5.8 $ 1.2 Provision for bad debts 4.2 6.0 5.3 Deductions: Charge-offs (5.7 ) (0.6 ) (0.7 ) Balance, end of year $ 9.7 $ 11.2 $ 5.8

Physical Commodities Inventor37

Physical Commodities Inventory Physical Commodities Inventory (Tables)	12 Months Ended
	Sep. 30, 2016
Inventory [Line Items]
Schedule of Inventory, Current [Table Text Block]	(in millions) September 30, September 30, Physical Ag & Energy (1) $ 65.9 $ 0.4 Precious metals - held by broker-dealer subsidiary (2) 5.3 10.8 Precious metals - held by non-broker-dealer subsidiaries (3) 52.6 21.6 Physical commodities inventory $ 123.8 $ 32.8

Property and Equipment, net (Ta

Property and Equipment, net (Tables)	12 Months Ended
	Sep. 30, 2016
Property and Equipment, net [Abstract]
Property, Plant and Equipment [Table Text Block]	A summary of property and equipment, at cost less accumulated depreciation as of September 30, 2016 and 2015 is as follows: (in millions) September 30, 2016 September 30, 2015 Property and equipment: Furniture and fixtures $ 6.8 $ 5.2 Software 22.8 9.0 Equipment 20.6 16.1 Leasehold improvements 11.9 9.9 Total property and equipment 62.1 40.2 Less accumulated depreciation (32.7 ) (20.5 ) Property and equipment, net $ 29.4 $ 19.7

Goodwill (Tables)

Goodwill (Tables)	12 Months Ended
	Sep. 30, 2016
Goodwill [Abstract]
Schedule of Goodwill [Table Text Block]	Goodwill allocated to the Company’s operating segments as of September 30, 2016 and 2015 is as follows: (in millions) September 30, September 30, Commercial Hedging $ 30.7 $ 30.7 Global Payments 6.3 6.3 Physical Commodities 2.4 2.4 Securities 8.1 8.1 Goodwill $ 47.5 $ 47.5

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Sep. 30, 2016
Intangible Assets [Abstract]
Schedule of Finite and Indefinite-Lived Intangible Assets [Table Text Block]	The gross and net carrying values of intangible assets as of the balance sheet dates, by major intangible asset class are as follows: September 30, 2016 September 30, 2015 (in millions) Gross Amount Accumulated Amortization Net Amount Gross Amount Accumulated Amortization Net Amount Intangible assets subject to amortization: Trade name $ 1.1 $ (0.6 ) $ 0.5 $ — $ — $ — Software programs/platforms 2.7 (2.4 ) 0.3 2.7 (2.3 ) 0.4 Customer base 14.0 (5.7 ) 8.3 14.0 (4.9 ) 9.1 17.8 (8.7 ) 9.1 16.7 (7.2 ) 9.5 Intangible assets not subject to amortization: Trade name — — — 1.1 — 1.1 Total intangible assets $ 17.8 $ (8.7 ) $ 9.1 $ 17.8 $ (7.2 ) $ 10.6
Schedule of Expected Amortization Expense [Table Text Block]	Amortization expense related to intangible assets was $1.6 million , $1.5 million , and $1.6 million for the fiscal years ended September 30, 2016, 2015, and 2014 , respectively. The estimated future amortization expense as of September 30, 2016 is as follows (in millions): Year ending September 30, 2017 $ 1.6 2018 1.0 2019 1.0 2020 0.8 2021 and thereafter 4.7 $ 9.1

Credit Facilities (Tables)

Credit Facilities (Tables)	12 Months Ended
	Sep. 30, 2016
Credit Facilities [Abstract]
Schedule of Debt [Table Text Block]	The following table sets forth a listing of credit facilities, the current committed amounts, as of the report date, on the facilities, and outstanding borrowings on the facilities as well as indebtedness on a promissory note an on senior notes as of September 30, 2016 and 2015 : (in millions) Credit Facilities Amounts Outstanding Borrower Security Renewal / Expiration Date Total Commitment September 30, September 30, INTL FCStone Inc. Certain pledged shares of certain subsidiaries March 18, 2019 $ 247.0 $ 136.5 $ 28.0 INTL FCStone Financial None April 6, 2017 75.0 — — INTL FCStone Financial Commodity warehouse receipts n/a — — — FCStone Merchants Certain commodities assets May 1, 2018 100.0 43.5 10.0 INTL FCStone Ltd None October 27, 2017 25.0 — — $ 447.0 180.0 38.0 Note Payable to Bank Monthly installments, due March 2020 and secured by certain equipment 2.8 3.6 Senior Unsecured Notes 8.50% senior notes, redeemed October 15, 2016 45.5 45.5 Total indebtedness $ 228.3 $ 87.1

Commitments and Contingencies F

Commitments and Contingencies Future Minimum Lease Commitments (Tables)	12 Months Ended
	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	Future aggregate minimum lease payments under noncancelable operating leases as of September 30, 2016 are as follows: (in millions) Year ending September 30, 2017 $ 8.8 2018 7.1 2019 6.6 2020 6.3 2021 5.5 Thereafter 10.5 $ 44.8

Regulatory Requirements and S43

Regulatory Requirements and Subsidiary Dividend Restrictions (Tables)	12 Months Ended
	Sep. 30, 2016
Capital and Other Regulatory Requirements [Abstract]
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block]	All subsidiaries of the Company are in compliance with all of their regulatory requirements as of September 30, 2016 , as follows: (in millions) As of September 30, 2016 Subsidiary Regulatory Authority Requirement Type Actual Minimum Requirement INTL FCStone Financial Inc. SEC and CFTC Net capital $ 140.8 $ 81.7 INTL FCStone Financial Inc. CFTC Segregated funds $ 2,177.9 $ 2,126.4 INTL FCStone Financial Inc. CFTC Secured funds $ 107.7 $ 91.3 Sterne Agee Clearing Inc. SEC Net capital $ 1.0 $ 0.1 Sterne, Agee & Leach, Inc. SEC Net capital $ 29.0 $ 2.0 Sterne Agee Financial Services, Inc. SEC Net capital $ 3.3 $ 0.3 INTL FCStone Ltd FCA (United Kingdom) Net capital $ 136.9 $ 84.9 INTL FCStone Ltd FCA (United Kingdom) Segregated funds $ 54.8 $ 49.5 INTL Netherlands BV FCA (United Kingdom) Net capital $ 136.1 $ 85.0 INTL FCStone DTVM Ltda. Brazilian Central Bank and Securities and Exchange Commission of Brazil Capital adequacy $ 2.5 $ 0.5 INTL Gainvest S.A. National Securities Commission ("CNV") Capital adequacy $ 7.7 $ 0.1 INTL Gainvest S.A. CNV Net capital $ 3.6 $ 0.1 INTL Capital S.A. General Inspector of Justice (Argentina) Net capital $ 15.3 $ 12.6 INTL CIBSA S.A. CNV Capital adequacy $ 7.1 $ 1.1 INTL CIBSA S.A. CNV Net capital $ 10.9 $ 0.6
Schedule of Regulatory Assets [Table Text Block]	Funds deposited by customers and other assets, which have been segregated as belonging to the commodity customers as of September 30, 2016 and 2015 , are as follows: (in millions) September 30, 2016 September 30, 2015 Cash, at banks - segregated $ 383.6 $ 126.9 Securities representing investments of customers' funds, at banks 595.4 492.5 Securities held for customers in lieu of cash, at banks 1.8 0.9 Deposits with and receivables from: Exchange-clearing organizations, including securities, net of omnibus eliminations 1,173.9 1,237.8 Securities held for customers in lieu of cash 23.2 22.1 Total customer-segregated funds 2,177.9 1,880.2 Amount required to be segregated 2,126.4 1,830.9 Excess funds in segregation $ 51.5 $ 49.3 Funds deposited by customers and other assets, which are held in separate accounts for customers trading foreign futures and foreign options customers, as of September 30, 2016 and 2015 are as follows: (in millions) September 30, 2016 September 30, 2015 Cash - secured $ 70.5 $ 64.7 Securities — — Equities with registered futures commission merchants 3.6 2.6 Amounts held by clearing organizations of foreign boards of trade 6.7 — Amounts held by members of foreign boards of trade 26.9 18.3 Total customer-secured funds 107.7 85.6 Amount required to be secured 91.3 65.2 Excess secured funds $ 16.4 $ 20.4

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Sep. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	Fair value is estimated at the grant date based on a Black-Scholes-Merton option-pricing model using the following weighted-average assumptions: Year Ended September 30, 2016 2015 2014 Expected stock price volatility 28 % 28 % 34 % Expected dividend yield — % — % — % Risk free interest rate 0.83 % 0.66 % 0.80 % Average expected life (in years) 3.06 3.22 2.88
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]	The following is a summary of stock option activity for the year ended September 30, 2016 : Shares Available for Grant Number of Options Outstanding Weighted Average Exercise Price Weighted Average Grant Date Fair Value Weighted Average Remaining Term (in years) Aggregate Intrinsic Value ($ millions) Balances at September 30, 2015 828,665 1,297,984 $ 28.28 $ 12.37 4.24 $ 1.8 Granted (90,500 ) 90,500 $ 31.37 $ 6.40 Exercised (147,205 ) $ 18.52 $ 1.50 Forfeited 15,998 (16,498 ) $ 25.23 $ 5.28 Expired (8,960 ) $ 54.23 $ 20.04 Balances at September 30, 2016 754,163 1,215,821 $ 29.55 $ 12.88 3.80 $ 14.1 Exercisable at September 30, 2016 306,520 $ 40.58 $ 15.09 0.92 $ 2.2
Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]	The options outstanding as of September 30, 2016 broken down by exercise price are as follows: Exercise Price Number of Options Outstanding Weighted Average Exercise Price Weighted Average Remaining Term $ — - $ 5.00 — n/a n/a $ 5.00 - $ 10.00 — n/a n/a $ 10.00 - $ 15.00 — n/a n/a $ 15.00 - $ 20.00 75,325 $ 18.77 1.00 $ 20.00 - $ 25.00 156,997 $ 22.07 1.73 $ 25.00 - $ 30.00 720,000 $ 25.91 5.38 $ 30.00 - $ 35.00 83,000 $ 31.37 3.28 $ 35.00 - $ 40.00 — n/a n/a $ 40.00 - $ 45.00 — n/a n/a $ 45.00 - $ 50.00 — n/a n/a $ 50.00 - $ 55.00 180,499 $ 54.23 0.68 1,215,821 $ 29.55 3.80
Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block]	The following is a summary of restricted stock activity through September 30, 2016 : Shares Available for Grant Number of Shares Outstanding Weighted Average Grant Date Fair Value Weighted Average Remaining Term (in years) Aggregate Intrinsic Value ($ millions) Balances at September 30, 2015 974,919 230,043 $ 20.10 2.17 $ 5.7 Granted (229,886 ) 229,886 $ 31.40 Vested (99,428 ) $ 19.84 Forfeited 2,749 (2,749 ) $ 21.89 Balances at September 30, 2016 747,782 357,752 $ 27.39 1.39 $ 13.9

Other Expenses (Tables)

Other Expenses (Tables)	12 Months Ended
	Sep. 30, 2016
Other Expenses [Abstract]
Schedule of Other Operating Cost and Expense, by Component [Table Text Block]	Other expenses for the years ended September 30, 2016, 2015, and 2014 are comprised of the following: Year Ended September 30, (in millions) 2016 2015 2014 Contingent consideration, net (1) 0.4 1.8 (2.0 ) Insurance 2.1 1.7 1.6 Advertising, meetings and conferences 5.1 2.7 3.1 Non-trading hardware and software maintenance and software licensing 7.1 4.7 3.8 Office supplies and printing 1.1 1.2 1.1 Other clearing related expenses 1.3 1.1 1.2 Other non-income taxes 4.3 3.7 3.9 Other 8.0 6.6 5.7 Total other expenses $ 29.4 $ 23.5 $ 18.4 (1) Contingent consideration includes remeasurement of contingent liabilities related to business combinations accounted for in accordance with the provisions of the Business Combinations Topic of the ASC (see Note 3 ).

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	Income tax expense (benefit) for the years ended September 30, 2016, 2015, and 2014 was allocated as follows: Year Ended September 30, (in millions) 2016 2015 2014 Income tax expense attributable to income from continuing operations $ 18.0 $ 22.4 $ 6.4 Income tax (benefit) expense attributable to loss from discontinued operations — — (0.2 ) Taxes allocated to stockholders’ equity, related to unrealized gains (losses) on available-for-sale securities — (0.4 ) 0.1 Taxes allocated to stockholders’ equity, related to pension liabilities 0.2 (0.8 ) (0.5 ) Taxes allocated to additional paid-in capital, related to share-based compensation (0.8 ) (0.5 ) 0.1 Total income tax expense $ 17.4 $ 20.7 $ 5.9 The components of the provision for income taxes attributable to income from continuing operations were as follows: Year Ended September 30, (in millions) 2016 2015 2014 Current taxes: U.S. federal $ 1.3 $ 0.8 $ 0.5 U.S. State and local 0.8 1.2 — International 16.8 15.4 11.6 Total current taxes 18.9 17.4 12.1 Deferred taxes (0.8 ) 5.0 (5.7 ) Income tax benefit attributable to interest income $ (0.1 ) $ — $ — Income tax expense $ 18.0 $ 22.4 $ 6.4
Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]	U.S. and international components of (loss) income from continuing operations, before income taxes, was as follows: Year Ended September 30, (in millions) 2016 2015 2014 U.S. $ 4.9 $ 14.5 $ (13.0 ) International 67.9 63.7 39.0 Income from continuing operations, before tax $ 72.8 $ 78.2 $ 26.0
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	Items accounting for the difference between income taxes computed at the federal statutory rate and the provision for income taxes were as follows: Year Ended September 30, 2016 2015 2014 Federal statutory rate effect of: 35.0 % 35.0 % 35.0 % U.S. State and local income taxes 1.3 % 1.8 % — % Foreign earnings taxed at lower rates (9.3 )% (10.1 )% (14.7 )% Change in foreign valuation allowance (0.3 )% (0.1 )% 1.9 % Change in state valuation allowance — % 0.6 % (0.2 )% Uncertain tax positions — % — % (0.5 )% U.S. permanent items 0.8 % 0.5 % 1.9 % Foreign permanent items 0.2 % 1.1 % 7.0 % U.S. bargain purchase gain (3.0 )% — % — % Other reconciling items 0.3 % (0.1 )% (5.7 )% Effective rate 25.0 % 28.7 % 24.7 %
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	The components of deferred income tax assets and liabilities were as follows: (in millions) September 30, 2016 September 30, 2015 Deferred tax assets: Share-based compensation $ 4.3 $ 3.2 Pension liability 1.9 2.7 Deferred compensation 2.0 2.3 Foreign net operating loss carryforwards 2.0 2.3 U.S. State and local net operating loss carryforwards 4.9 4.3 U.S. federal net operating loss carryforwards 12.4 8.6 Intangible assets 8.3 4.6 Capital loss carryforwards — 0.2 Bad debt reserve 1.6 2.4 Tax Credit Carryforwards 1.4 1.0 Other compensation 3.3 1.9 Other 1.8 1.3 Total gross deferred tax assets 43.9 34.8 Less valuation allowance (3.6 ) (3.2 ) Deferred tax assets 40.3 31.6 Deferred income tax liabilities: Unrealized gain on securities 1.3 1.0 Prepaid expenses 1.9 1.1 Fixed assets 2.6 1.3 Deferred income tax liabilities 5.8 3.4 Deferred income taxes, net $ 34.5 $ 28.2
Summary of Income Tax Contingencies [Table Text Block]	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: Year Ended September 30, (in millions) 2016 2015 2014 Balance, beginning of year $ — $ — $ 0.1 Gross increases for tax positions related to current year — — — Gross increases for tax positions related to prior years 0.1 — — Gross decreases for tax positions of prior years — — (0.1 ) Settlements — — — Lapse of statute of limitations — — — Balance, end of year $ 0.1 $ — $ —

Accumulated Other Comprehensi47

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Sep. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following table summarizes the changes in accumulated other comprehensive income (loss) for the year ended September 30, 2016 . (in millions) Foreign Currency Translation Adjustment Pension Benefits Adjustment Accumulated Other Comprehensive Loss Balances as of September 30, 2015 $ (12.7 ) $ (4.8 ) $ (17.5 ) Other comprehensive income (loss), net of tax before reclassifications (7.4 ) (0.2 ) (7.6 ) Amounts reclassified from AOCI, net of tax — 0.5 0.5 Other comprehensive income (loss), net of tax (7.4 ) 0.3 (7.1 ) Balances as of September 30, 2016 $ (20.1 ) $ (4.5 ) $ (24.6 )

Discontinued Operations (Tables

Discontinued Operations (Tables)	12 Months Ended
	Sep. 30, 2016
Discontinued Operations and Disposal Groups [Abstract]
Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures [Table Text Block]	Summarized below are the components of the Company’s loss from discontinued operations for the years ended September 30, 2016, 2015, and 2014 : Year Ended September 30, (in millions) 2016 2015 2014 Revenues from discontinued operations $ — $ — $ 40.9 Cost of sales of physical commodities from discontinued operations — — 40.2 Operating revenues $ — $ — $ 0.7 Loss from discontinued operations before income taxes $ — $ — $ (0.5 ) Income tax benefit — — 0.2 Loss from discontinued operations, net of tax $ — $ — $ (0.3 )

Quarterly Financial Informati49

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Sep. 30, 2016
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information [Table Text Block]	The Company has set forth certain quarterly unaudited financial data for the past two years in the tables below: For the 2016 Fiscal Quarter Ended (in millions, except per share amounts) September 30 June 30 March 31 December 31 Total revenues $ 2,777.6 $ 4,868.5 $ 3,708.9 $ 3,399.9 Cost of sales of physical commodities 2,599.0 4,693.5 3,542.8 3,248.6 Operating revenues 178.6 175.0 166.1 151.3 Transaction-based clearing expenses 32.0 35.2 32.9 29.8 Introducing broker commissions 28.1 14.8 13.2 12.8 Interest expense 7.5 7.7 7.1 6.0 Net operating revenues 111.0 117.3 112.9 102.7 Compensation and other expenses 98.0 95.9 92.9 90.6 Gain on acquisition 6.2 — — — Income before tax 19.2 21.4 20.0 12.1 Income tax expense 2.4 6.8 5.5 3.3 Net income $ 16.8 $ 14.6 $ 14.5 $ 8.8 Net basic earnings per share $ 0.91 $ 0.79 $ 0.77 $ 0.47 Net diluted earnings per share $ 0.90 $ 0.78 $ 0.76 $ 0.46 For the 2015 Fiscal Quarter Ended (in millions, except per share amounts) September 30 June 30 March 31 December 31 Total revenues $ 2,628.4 $ 3,995.1 $ 14,442.0 $ 13,627.7 Cost of sales of physical commodities 2,449.7 3,843.5 14,285.5 13,490.2 Operating revenues 178.7 151.6 156.5 137.5 Transaction-based clearing expenses 31.3 30.2 31.8 29.4 Introducing broker commissions 15.1 13.1 12.3 12.2 Interest expense 5.0 4.9 4.5 2.7 Net operating revenues 127.3 103.4 107.9 93.2 Compensation and other expenses 98.1 86.2 89.8 79.6 Income before tax 29.2 17.2 18.1 13.6 Income tax expense 8.1 5.0 5.1 4.2 Net income $ 21.1 $ 12.2 $ 13.0 $ 9.4 Net basic earnings per share $ 1.12 $ 0.64 $ 0.68 $ 0.50 Net diluted earnings per share $ 1.09 $ 0.62 $ 0.67 $ 0.49

Segment and Geographic Inform50

Segment and Geographic Information (Tables)	12 Months Ended
	Sep. 30, 2016
Segment Analysis [Abstract]
Schedule of Segment Reporting Information, by Segment [Table Text Block]	Information concerning operations in these segments of business is shown in accordance with the Segment Reporting Topic of the ASC as follows: Year Ended September 30, (in millions) 2016 2015 2014 Total revenues: Commercial Hedging $ 236.1 $ 262.4 $ 224.0 Global Payments 73.2 77.1 55.4 Securities 175.2 129.8 80.3 Physical Commodities 14,120.5 34,092.0 33,552.1 Clearing and Execution Services 151.1 123.4 113.7 Corporate unallocated (1.2 ) 8.5 (3.1 ) Total $ 14,754.9 $ 34,693.2 $ 34,022.4 Operating revenues (loss): Commercial Hedging $ 236.1 $ 262.4 $ 224.0 Global Payments 73.2 77.1 55.4 Securities 175.2 129.8 80.3 Physical Commodities 36.6 23.1 20.6 Clearing and Execution Services 151.1 123.4 113.7 Corporate unallocated (1.2 ) 8.5 (3.1 ) Total $ 671.0 $ 624.3 $ 490.9 Net operating revenues (loss): Commercial Hedging $ 188.2 $ 214.7 $ 180.5 Global Payments 65.3 68.5 48.2 Securities 121.9 88.6 54.6 Physical Commodities 31.5 21.2 17.9 Clearing and Execution Services 48.8 38.3 29.7 Corporate unallocated (11.8 ) 0.5 (8.9 ) Total $ 443.9 $ 431.8 $ 322.0 Net contribution: (Revenues less cost of sales, transaction-based clearing expenses, variable bonus compensation, introducing broker commissions and interest expense): Commercial Hedging $ 134.4 $ 151.7 $ 132.6 Global Payments 52.2 54.5 37.6 Securities 97.5 67.4 40.9 Physical Commodities 23.4 16.9 14.1 Clearing and Execution Services 39.5 30.1 24.0 Total $ 347.0 $ 320.6 $ 249.2 Segment income: (Net contribution less non-variable direct segment costs): Commercial Hedging $ 68.7 $ 85.6 $ 67.3 Global Payments 39.8 43.3 28.3 Securities 69.4 40.5 21.0 Physical Commodities 13.3 5.8 5.9 Clearing and Execution Services 14.8 12.9 6.3 Total $ 206.0 $ 188.1 $ 128.8 Reconciliation of segment income to income from continuing operations, before tax: Segment income $ 206.0 $ 188.1 $ 128.8 Costs not allocated to operating segments 133.3 110.0 102.8 Income from continuing operations, before tax $ 72.7 $ 78.1 $ 26.0 (in millions) As of September 30, 2016 As of September 30, 2015 As of September 30, 2014 Total assets: Commercial Hedging $ 1,637.5 $ 1,548.1 $ 1,400.9 Global Payments 191.4 207.3 51.9 Securities 2,130.7 1,861.0 235.5 Physical Commodities 258.0 190.9 116.8 Clearing and Execution Services 1,617.4 1,163.8 1,136.2 Corporate unallocated 116.3 98.9 98.4 Total $ 5,951.3 $ 5,070.0 $ 3,039.7
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block]	Information regarding revenues and operating revenues for the years ended September 30, 2016, 2015, and 2014 , and information regarding long-lived assets (defined as property, equipment, leasehold improvements and software) as of September 30, 2016, 2015, and 2014 in geographic areas were as follows: Year Ended September 30, (in millions) 2016 2015 2014 Total revenues: United States $ 817.1 $ 25,959.0 $ 19,055.3 Europe 463.5 121.2 86.0 South America 64.8 49.0 53.2 Asia 13,405.1 8,560.0 14,822.4 Other 4.4 4.0 5.5 Total $ 14,754.9 $ 34,693.2 $ 34,022.4 Operating revenues: United States $ 457.0 $ 424.3 $ 330.4 Europe 120.2 125.0 86.0 South America 64.8 49.0 53.2 Asia 24.6 21.9 15.8 Other 4.4 4.1 5.5 Total $ 671.0 $ 624.3 $ 490.9 (in millions) As of September 30, 2016 As of September 30, 2015 As of September 30, 2014 Long-lived assets, as defined: United States $ 23.3 $ 13.8 $ 8.5 Europe 4.8 4.0 5.0 South America 1.2 1.7 2.0 Asia 0.1 0.2 0.3 Other — — 0.1 Total $ 29.4 $ 19.7 $ 15.9

Description of Business and S51

Description of Business and Significant Accounting Policies - Accounts, Customers and Other Facts (Details)	12 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Number of different types of foreign currencies	140
Number of accounts for customers company-wide	20,000

Description of Business and S52

Description of Business and Significant Accounting Policies - Cash, Cash Equivalents, Securities (Details) - USD ($)	Sep. 30, 2016	Sep. 30, 2015
Accounting Policies [Abstract]
Cash Held at Banks and Money Market Funds - Segregated	$ 515,200,000	$ 240,000,000
US Government Obligations and other securities	595,500,000	493,400,000
Commodities Warehouse Receipts	23,300,000	22,100,000
Cash and Cash Equivalents - Deposits and Receivables	900,000,000	900,000,000
US Government Securities and Other Securities - Deposits and Receivables	471,738,813	502,483,279
Memberships in Exchanges Owned	12,100,000	9,900,000
Fair Value of Exchange Memberships	$ 9,100,000	$ 7,600,000

Description of Business and S53

Description of Business and Significant Accounting Policies - Notes Receivable - Participation (Details)	Sep. 30, 2016
Minimum [Member]
Short Term Notes Receivable Outstanding Balance Threshold, Percentage	90.00%
Maximum [Member]
Short Term Notes Receivable Outstanding Balance Threshold, Percentage	98.00%

Description of Business and S54

Description of Business and Significant Accounting Policies - Additional Paid In Capital (Provident Shares Held In Escrow) (Details) - USD ($)	1 Months Ended	12 Months Ended				13 Months Ended
	Sep. 30, 2010	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2012	Sep. 30, 2011
US Government Securities and Other Securities - Deposits and Receivables		$ 471,738,813	$ 502,483,279
Business Combination, Consideration Transferred		$ 45,000,000
Provident Group Asset Acquisition [Member]
Business Combination, Consideration Transferred					$ 5,000,000
Business Combination, Cost of Acquired Entity, Equity Interest Issued or Issuable, Total Shares Purchased and Placed In Escrow						214,325
Business Combination, Cost of Acquired Entity, Equity Interest Issued or Issuable, Period From Date of Closing Over Which Shares Will be Released from Escrow	5 years
Stock Redeemed or Called During Period, Shares			204,271
Business Combination, Cost of Acquired Entity, Equity Interest Issued or Issuable, Shares Released from Escrow			0	10,054

Description of Business and S55

Description of Business and Significant Accounting Policies - Basis of Presentation and Consolidation (Details) - USD ($)	Sep. 30, 2016	Sep. 30, 2015
Accounting Policies [Abstract]
Cash and Cash Equivalents - Deposits and Receivables	$ 900,000,000	$ 900,000,000
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Stock, Shares Outstanding	0	0
US Government Securities and Other Securities - Deposits and Receivables	$ 471,738,813	$ 502,483,279

Earnings per Share - EPS Reconc

Earnings per Share - EPS Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Income from Continuing Operations	$ 54.7	$ 55.7	$ 19.6
Undistributed Earnings Allocated to Participating Securities - Continuing Operations	(1)	(1.3)	(0.5)
Income from continuing operations allocated to common shareholders	53.7	54.4	19.1
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0	0	(0.3)
Undistributed Earnings Allocated to Participating Securities - Discontinued Operations	0	0	0
Income from discontinued operations allocated to common shareholders	0	0	(0.3)
Diluted net income	54.7	55.7	19.3
Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted	(1)	(1.3)	(0.5)
Diluted net income allocated to common shareholders	$ 53.7	$ 54.4	$ 18.8
Weighted Average Number of Shares Outstanding, Basic	18,410,561	18,525,374	18,528,302
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Share-based Awards For Diluted Earnings Per Share Calculation	214,811	406,861	604,000
Diluted weighted-average shares	18,625,372	18,932,235	19,132,302

Earnings per Share - Antiduliti

Earnings per Share - Antidulitive Securities (Details) - shares	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	910,060	997,459	1,120,985

Assets and Liabilities, at Fa58

Assets and Liabilities, at Fair Value Assets and Liabilities, at Fair Value - Financial Instruments at Fair Value Disclosure (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Assets and Liabilities, at Fair Value [Abstract]
Long-term Debt, Fair Value	$ 46.2	$ 46.6
Senior Notes	$ 45.5	$ 45.5

Assets and Liabilities, at Fa59

Assets and Liabilities, at Fair Value - Financial Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Securities Segregated under Federal and Other Regulations	$ 1,136.3	$ 756.9
Receivables from Exchange Clearing Organizations	1,524.4	1,533.5
Receivables from Brokers-Dealers and Clearing Organizations	237	277.6
Financial instruments owned, at fair value	1,606.1	1,421.9
Physical Commodities Inventory	123.8	32.8
Assets, Fair Value Disclosure	3,156.5
Accounts payable and other accrued liabilities	161.3	144.8
Payables to Broker-Dealers and Clearing Organizations	260.1	262.9
Financial Instruments Sold, Not yet Purchased, at Fair Value	839.4	568.3
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure		1.3
Cash and Securities Segregated under Federal and Other Regulations	618.8	515.5
Receivables from Exchange Clearing Organizations	868.5	1,009.4
Receivables from Brokers-Dealers and Clearing Organizations	(15.2)	(52.9)
Financial instruments owned, at fair value	1,606.1	1,421.9
Assets, Fair Value Disclosure	3,156.5	2,910.4
Payables to Broker-Dealers and Clearing Organizations	3.5
Financial Instruments Sold, Not yet Purchased, at Fair Value	839.4	568.3
Liabilities, Fair Value Disclosure	843.7	573.2
Fair Value, Measurements, Recurring [Member] | TBA and forward settling securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payables to Broker-Dealers and Clearing Organizations	3.5	1.6
Fair Value, Measurements, Recurring [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payables to Broker-Dealers and Clearing Organizations	0	0
Fair Value, Measurements, Recurring [Member] | Contingent Consideration [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accounts payable and other accrued liabilities	0.8	3.3
Fair Value, Measurements, Recurring [Member] | Physical commodities inventory[Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Physical Commodities Inventory	71.2	15.2
Fair Value, Measurements, Recurring [Member] | Common stock and American Depositary Receipts (ADRs) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	36.5	26.1
Financial Instruments Sold, Not yet Purchased, at Fair Value	23.9	18.6
Fair Value, Measurements, Recurring [Member] | Exchangeable foreign ordinary equities and ADRs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	25.7	89.5
Financial Instruments Sold, Not yet Purchased, at Fair Value	25.8	90
Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	40.8	31.3
Financial Instruments Sold, Not yet Purchased, at Fair Value	6.9
Fair Value, Measurements, Recurring [Member] | US Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	514.9	513.4
Financial Instruments Sold, Not yet Purchased, at Fair Value	509.8	341
Fair Value, Measurements, Recurring [Member] | Foreign Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	14.6	12.1
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	6.4
Fair Value, Measurements, Recurring [Member] | Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	747.5	699.5
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	2.8
Fair Value, Measurements, Recurring [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	193.9	30.6
Financial Instruments Sold, Not yet Purchased, at Fair Value	210.9	54.1
Fair Value, Measurements, Recurring [Member] | Commodities leases and unpriced positions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	8.1	7.6
Financial Instruments Sold, Not yet Purchased, at Fair Value	62.1	55.4
Fair Value, Measurements, Recurring [Member] | Commodities warehouse receipts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	8.9	2.8
Fair Value, Measurements, Recurring [Member] | Exchange firm common stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	6.4
Fair Value, Measurements, Recurring [Member] | Mutual funds and other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	8.8	3.4
Fair Value, Measurements, Recurring [Member] | TBA and forward settling securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Brokers-Dealers and Clearing Organizations	0.3	0.2
Fair Value, Measurements, Recurring [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Brokers-Dealers and Clearing Organizations	(15.5)	(53.1)
Fair Value, Measurements, Recurring [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Exchange Clearing Organizations	512.7	431.8
Fair Value, Measurements, Recurring [Member] | US Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Exchange Clearing Organizations	472.1	501.4
Fair Value, Measurements, Recurring [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Exchange Clearing Organizations	(116.3)	76.2
Fair Value, Measurements, Recurring [Member] | Commodities warehouse receipts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Securities Segregated under Federal and Other Regulations	23.3	22.1
Fair Value, Measurements, Recurring [Member] | US Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Securities Segregated under Federal and Other Regulations	595.5	493.4
Fair Value, Measurements, Recurring [Member] | Certificates of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	7.1
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure		1.3
Cash and Securities Segregated under Federal and Other Regulations	23.3	22.1
Receivables from Exchange Clearing Organizations	2,662.6	4,047.7
Receivables from Brokers-Dealers and Clearing Organizations	0	0.1
Financial instruments owned, at fair value	327.7	423
Assets, Fair Value Disclosure	3,091.9	4,509.4
Payables to Broker-Dealers and Clearing Organizations	1,961.7
Financial Instruments Sold, Not yet Purchased, at Fair Value	255.1	371
Liabilities, Fair Value Disclosure	2,216.8	3,862.3
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | TBA and forward settling securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payables to Broker-Dealers and Clearing Organizations	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payables to Broker-Dealers and Clearing Organizations	1,961.7	3,491.3
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Contingent Consideration [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accounts payable and other accrued liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Physical commodities inventory[Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Physical Commodities Inventory	71.2	15.2
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Common stock and American Depositary Receipts (ADRs) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	34.6	23.7
Financial Instruments Sold, Not yet Purchased, at Fair Value	23.5	18
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Exchangeable foreign ordinary equities and ADRs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	25.2	82.9
Financial Instruments Sold, Not yet Purchased, at Fair Value	25.3	89
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	36.9	26.1
Financial Instruments Sold, Not yet Purchased, at Fair Value	6.9
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | US Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Foreign Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	206.9	278.5
Financial Instruments Sold, Not yet Purchased, at Fair Value	199.4	264
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Commodities leases and unpriced positions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Commodities warehouse receipts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	8.9	2.8
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Exchange firm common stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	6.4	5.6
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Mutual funds and other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	8.8	3.4
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | TBA and forward settling securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Brokers-Dealers and Clearing Organizations	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Brokers-Dealers and Clearing Organizations	0	0.1
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Exchange Clearing Organizations	512.7	431.8
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | US Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Exchange Clearing Organizations	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Exchange Clearing Organizations	2,149.9	3,615.9
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Commodities warehouse receipts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Securities Segregated under Federal and Other Regulations	23.3	22.1
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | US Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Securities Segregated under Federal and Other Regulations	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Certificates of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	7.1
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure		0
Cash and Securities Segregated under Federal and Other Regulations	595.5	493.4
Receivables from Exchange Clearing Organizations	472.1	501.4
Receivables from Brokers-Dealers and Clearing Organizations	8.3	539.1
Financial instruments owned, at fair value	2,768.1	3,002.1
Assets, Fair Value Disclosure	3,844	4,536
Payables to Broker-Dealers and Clearing Organizations	100.1
Financial Instruments Sold, Not yet Purchased, at Fair Value	2,037.8	2,174.4
Liabilities, Fair Value Disclosure	2,137.9	2,705.7
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | TBA and forward settling securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payables to Broker-Dealers and Clearing Organizations	2.6	2.6
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payables to Broker-Dealers and Clearing Organizations	97.5	528.7
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Contingent Consideration [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accounts payable and other accrued liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Physical commodities inventory[Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Physical Commodities Inventory	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Common stock and American Depositary Receipts (ADRs) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	1.7	1.9
Financial Instruments Sold, Not yet Purchased, at Fair Value	0.4	0.6
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Exchangeable foreign ordinary equities and ADRs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0.5	6.6
Financial Instruments Sold, Not yet Purchased, at Fair Value	0.5	1
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0.9	2
Financial Instruments Sold, Not yet Purchased, at Fair Value	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | US Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	514.9	513.4
Financial Instruments Sold, Not yet Purchased, at Fair Value	509.8	341
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	14.6	12.1
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	6.4
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	747.5	699.5
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	2.8
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	1,350.8	1,702
Financial Instruments Sold, Not yet Purchased, at Fair Value	1,319.3	1,723.5
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Commodities leases and unpriced positions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	137.2	64.6
Financial Instruments Sold, Not yet Purchased, at Fair Value	207.8	99.1
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Commodities warehouse receipts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Exchange firm common stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Mutual funds and other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | TBA and forward settling securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Brokers-Dealers and Clearing Organizations	0.3	1.2
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Brokers-Dealers and Clearing Organizations	8	537.9
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Exchange Clearing Organizations	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | US Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Exchange Clearing Organizations	472.1	501.4
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Exchange Clearing Organizations	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Commodities warehouse receipts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Securities Segregated under Federal and Other Regulations	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | US Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Securities Segregated under Federal and Other Regulations	595.5	493.4
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Certificates of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure		0
Cash and Securities Segregated under Federal and Other Regulations	0	0
Receivables from Exchange Clearing Organizations	0	0
Receivables from Brokers-Dealers and Clearing Organizations	0	0
Financial instruments owned, at fair value	3.2	3.7
Assets, Fair Value Disclosure	3.2	3.7
Payables to Broker-Dealers and Clearing Organizations	0
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Liabilities, Fair Value Disclosure	0.8	3.3
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | TBA and forward settling securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payables to Broker-Dealers and Clearing Organizations	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payables to Broker-Dealers and Clearing Organizations	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Contingent Consideration [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accounts payable and other accrued liabilities	0.8	3.3
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Physical commodities inventory[Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Physical Commodities Inventory	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Common stock and American Depositary Receipts (ADRs) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0.2	0.5
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Exchangeable foreign ordinary equities and ADRs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	3	3.2
Financial Instruments Sold, Not yet Purchased, at Fair Value	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | US Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Foreign Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Commodities leases and unpriced positions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Commodities warehouse receipts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Exchange firm common stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Mutual funds and other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | TBA and forward settling securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Brokers-Dealers and Clearing Organizations	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Brokers-Dealers and Clearing Organizations	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Exchange Clearing Organizations	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | US Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Exchange Clearing Organizations	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Exchange Clearing Organizations	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Commodities warehouse receipts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Securities Segregated under Federal and Other Regulations	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | US Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Securities Segregated under Federal and Other Regulations	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Certificates of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0
Derivative [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payables to Broker-Dealers and Clearing Organizations		1.6
Derivative [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payables to Broker-Dealers and Clearing Organizations		3,491.3
Derivative [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payables to Broker-Dealers and Clearing Organizations		531.3
Derivative [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payables to Broker-Dealers and Clearing Organizations		0
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure		0
Cash and Securities Segregated under Federal and Other Regulations	0	0
Receivables from Exchange Clearing Organizations	(2,266.2)	(3,539.7)
Receivables from Brokers-Dealers and Clearing Organizations	(23.5)	(592.1)
Financial instruments owned, at fair value	(1,492.9)	(2,006.9)
Assets, Fair Value Disclosure	(3,782.6)	(6,138.7)
Payables to Broker-Dealers and Clearing Organizations	(2,058.3)
Financial Instruments Sold, Not yet Purchased, at Fair Value	(1,453.5)	(1,977.1)
Liabilities, Fair Value Disclosure	(3,511.8)	(5,998.1)
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | TBA and forward settling securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payables to Broker-Dealers and Clearing Organizations	0.9	(1)
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payables to Broker-Dealers and Clearing Organizations	(2,059.2)	(4,020)
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | Contingent Consideration [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accounts payable and other accrued liabilities	0	0
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | Physical commodities inventory[Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Physical Commodities Inventory	0	0
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | Common stock and American Depositary Receipts (ADRs) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | Exchangeable foreign ordinary equities and ADRs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Financial Instruments Sold, Not yet Purchased, at Fair Value	0
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | US Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | Foreign Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Financial Instruments Sold, Not yet Purchased, at Fair Value	0	0
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	(1,363.8)	(1,949.9)
Financial Instruments Sold, Not yet Purchased, at Fair Value	(1,307.8)	(1,933.4)
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | Commodities leases and unpriced positions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	(129.1)	(57)
Financial Instruments Sold, Not yet Purchased, at Fair Value	(145.7)	(43.7)
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | Commodities warehouse receipts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | Exchange firm common stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | Mutual funds and other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned, at fair value	0	0
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | TBA and forward settling securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Brokers-Dealers and Clearing Organizations	0	(1)
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Brokers-Dealers and Clearing Organizations	(23.5)	(591.1)
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Exchange Clearing Organizations	0	0
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | US Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Exchange Clearing Organizations	0	0
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivables from Exchange Clearing Organizations	(2,266.2)	(3,539.7)
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | Commodities warehouse receipts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Securities Segregated under Federal and Other Regulations	0	0
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | US Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Securities Segregated under Federal and Other Regulations	0	0
Counterparty And Cash Collateral Netting Adjustment [Member] | Fair Value, Measurements, Recurring [Member] | Certificates of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	$ 0
Counterparty And Cash Collateral Netting Adjustment [Member] | Derivative [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payables to Broker-Dealers and Clearing Organizations		$ (4,021)

Assets and Liabilities, at Fa60

Assets and Liabilities, at Fair Value - Details of Level 3 Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Assets and Liabilities, at Fair Value [Abstract]
Total Level 3 Assets	$ 3.2	$ 3.7
Level 3 assets for which the company bears economic exposure	3.2	3.7
Assets	5,951.3	$ 5,070	$ 3,039.7
Assets, Fair Value Disclosure	$ 3,156.5
Total level 3 assets as a percentage of total assets	0.10%	0.10%
Level 3 assets for which the company bears economic exposure as a percertange of total assets	0.10%	0.10%
Total level 3 assets as a percentage of total financial assets at fair value	0.10%	0.10%

Assets and Liabilities, at Fa61

Assets and Liabilities, at Fair Value - Rollforward of Level 3 (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Rollforward of Level 3 Assets [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$ 3.7	$ 4.3
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)	(0.5)	(0.6)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	3.2	3.7	$ 4.3
Rollforward of Level 3 Liabilities [Roll Forward]
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	(0.4)	1.9	(1.8)
Contingent Consideration [Member]
Rollforward of Level 3 Liabilities [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	3.3	5.5
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	0	0
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	0.4	1.8	(2.3)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Period Increase (Decrease)		1.8
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases	0	0.1
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	(2.9)	(4.1)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Transfers, Net	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	0.8	3.3	5.5
Common stock and American Depositary Receipts (ADRs) [Member]
Rollforward of Level 3 Assets [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	0.5	0.7
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)	(0.3)	(0.2)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	0.2	0.5	0.7
Corporate Debt Securities [Member]
Rollforward of Level 3 Assets [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	3.2	3.6
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)	(0.2)	(0.4)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$ 3	$ 3.2	$ 3.6

Assets and Liabilities, at Fa62

Assets and Liabilities, at Fair Value - Suriwongse Bonds (Details) $ in Millions	Sep. 30, 2016USD ($)
Assets and Liabilities, at Fair Value [Abstract]
Suriwongse Debt Investment Balance	$ 3

Assets and Liabilities, at Fa63

Assets and Liabilities, at Fair Value - Contingent Consideration (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	$ (0.4)	$ 1.9	$ (1.8)
Contingent Consideration [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	$ 0.4	$ 1.8	$ (2.3)

Assets and Liabilities, at Fa64

Assets and Liabilities, at Fair Value - Available for Sale Securities in OCI (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Assets and Liabilities, at Fair Value [Abstract]
Equity Investments in Exchange Stock - Cost	$ 3.7	$ 3.7
Equity Investments in Exchange Stock - Fair Value	6.4	5.6
Proceeds from Sale of Exchange Stock		2.1
Gain (Loss) on Disposition of Exchange Stock		1.2
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax - AFS securities		(3.3)
Deferred Tax Liabilities, Accumulated Other Comprehensive Income - AFS Securities		2
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax	0	5.4	$ 0.1
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax	$ 0	$ 2.7	$ 0.2

Financial Instruments with Of65

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk - Obligations to Purchase Financial Instruments at a Future Date (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk [Abstract]
Financial Instruments Sold, Not yet Purchased, at Fair Value	$ 839.4	$ 568.3
Derivative, Fair Value, Net	$ 210.9

Financial Instruments with Of66

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk - Gross Derivative Assets and Liabilities by Type and Balance Sheet Location (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 3,715.9	$ 6,135.6
Derivative Liability, Fair Value, Gross Liability	3,580.5	6,010.1
Derivative, Fair Value, Net	210.9
Exchange-traded Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	2,022.1	3,443.6
Derivative Liability, Fair Value, Gross Liability	1,920.5	3,313.8
Over the Counter (OTC) Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1,217	1,621.2
Derivative Liability, Fair Value, Gross Liability	1,188.9	1,650.7
Foreign Exchange Forward [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	12.2	27.8
Derivative Liability, Fair Value, Gross Liability	7.5	20.6
Over the Counter (OTC) Foreign Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	346.5	892.2
Derivative Liability, Fair Value, Gross Liability	290.2	865.4
Exchange-traded interest rate contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	78.7	126.8
Derivative Liability, Fair Value, Gross Liability	120.5	136
Equity Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	39.1	22.8
Derivative Liability, Fair Value, Gross Liability	50.3	21
TBA and forward settling securities [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0.3	1.2
Derivative Liability, Fair Value, Gross Liability	2.6	2.6
TBA securities purchased [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0.8
Derivative Liability, Fair Value, Gross Liability	(0.8)
Derivative Asset, Notional Amount	(289.8)
Derivative Liability, Notional Amount	(485.5)
TBA securities sold [Member] [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1.3
Derivative Liability, Fair Value, Gross Liability	(1.7)
Derivative Asset, Notional Amount	(702.3)
Derivative Liability, Notional Amount	(754.3)
Forward settling securities purchased [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0.1
Derivative Asset, Notional Amount	(607.9)
Forward settling securities sold [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	0.2
Derivative Liability, Notional Amount	(470.4)
Deposits and receivables from exchange clearing organizations [Member]
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net	(116.3)	76.2
Deposits and receivables from broker-dealers, clearing organizations and counterparties [Member]
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net	(15.2)	(52.9)
Financial instruments owned [Member]
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net	193.9	30.6
Payable to broker-dealers, clearing organizations and counterparties [Member]
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net	3.5	1.6
Financial instrument sold, not yet purchased [Member]
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net	210.9	54.1
Counterparty And Cash Collateral Netting Adjustment [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Amount Offset Against Collateral	(3,653.5)	(6,081.7)
Derivative Liability, Fair Value, Amount Offset Against Collateral	$ (3,366.1)	$ (5,954.4)

Financial Instruments with Of67

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk - Derivatives Volume (Details) number in Millions, $ in Millions	12 Months Ended
	Sep. 30, 2016USD ($)	Sep. 30, 2015
Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk [Abstract]
Derivative, Notional Amount	$ 375
Derivative, Average Remaining Maturity	15 years
Derivative, Number of Instruments Held	4	4.1

Financial Instruments with Of68

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk - Realized Gains/Losses on Derivative Contracts (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Commodity Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Net	$ 41.8	$ 78.6	$ 65.7
Foreign Exchange Forward [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Net	9.7	7.5	7.5
Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Net	0.8	3.2	0
TBA and forward settling securities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Net	(14.4)	(5.1)	0
Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Net	$ 37.9	$ 84.2	$ 73.2

Receivables from customers, n69

Receivables from customers, net and notes receivable, net - Allowance for Customer Receivables (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Receivables from customers and notes receivable, net [Abstract]
Allowance for Doubtful Accounts Receivable	$ 9.5	$ 10.2

Receivables from customers, n70

Receivables from customers, net and notes receivable, net - Allowance for Notes Receivable (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Receivables from customers and notes receivable, net [Abstract]
Allowance Notes Receivable	$ 0.2	$ 1

Receivables from customers, n71

Receivables from customers, net and notes receivable, net - Bad Debt Expense and Recoveries (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for Doubtful Accounts	$ 4.4	$ 7.3	$ 5.5
Allowance for Doubtful Accounts Receivable, Period Increase (Decrease)	4.2	6.6	5.1
Allowance for Doubtful Accounts Receivable, Charge-offs	0.4	5.7	0.6	$ 0.7
Allowance for Doubtful Accounts Receivable, Recoveries	0.2
Commercial Hedging [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable, Period Increase (Decrease)	3.6		3.8
Allowance for Doubtful Accounts Receivable, Charge-offs		0.7	0.6
Allowance for Doubtful Accounts Receivable, Recoveries			0.2
Commercial Hedging [Member] | OTC Customer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable, Period Increase (Decrease)		2.3
Commercial Hedging [Member] | LME Customer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable, Period Increase (Decrease)		0.6
Physical Commodities Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable, Period Increase (Decrease)	0.4	2.8	0.9
Securities Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable, Period Increase (Decrease)	$ 0.4	0.5	$ 0.7
Securities Segment [Member] | Provident Group Asset Acquisition [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable, Period Increase (Decrease)		$ 1.1

Receivables from customers, n72

Receivables from customers, net and notes receivable, net - Allowance for Bad Debts Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Allowance for Doubtful Accounts Receivable [Roll Forward]
Allowance for Doubtful Accounts - Customer and Notes Receivable	$ 11.2	$ 5.8	$ 1.2
Provision for bad debts		4.2	6	$ 5.3
Allowance for Doubtful Accounts Receivable, Charge-offs	(0.4)	(5.7)	(0.6)	(0.7)
Allowance for Doubtful Accounts Receivable, Recoveries	0.2
Allowance for Doubtful Accounts - Customer and Notes Receivable	$ 9.7	$ 11.2	$ 5.8	$ 1.2

Receivables from customers, n73

Receivables from customers, net and notes receivable, net - Exim Bank Notes Receivable (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Insured short-term notes receivable	$ 5	$ 41.4
Obligations for participation rights	$ 4.6	$ 30.7
Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Short Term Notes Receivable Outstanding Balance Threshold, Percentage	90.00%
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Short Term Notes Receivable Outstanding Balance Threshold, Percentage	98.00%

Physical Commodities Inventor74

Physical Commodities Inventory - Physical Commodities Inventory by CIP and Finished (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Inventory [Line Items]
Agricultural Related Inventory	$ 65.9	$ 0.4
Precious Metals Inventory at fair value	5.3	10.8
Precious Metals Inventory at cost	52.6	21.6
Physical Commodities Inventory	$ 123.8	$ 32.8

Physical Commodities Inventor75

Physical Commodities Inventory - LCM Adjustments (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Physical Commodities Inventory [Abstract]
Inventory Adjustments	$ 0.6	$ 0.3

Property and Equipment, net (De

Property and Equipment, net (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Property, Plant and Equipment [Line Items]
Depreciation	$ 6.6	$ 5.7	$ 5.7
Furniture and Fixtures, Gross	6.8	5.2
Capitalized Computer Software, Gross	22.8	9
Machinery and Equipment, Gross	20.6	16.1
Leasehold Improvements, Gross	11.9	9.9
Property, Plant and Equipment, Gross	62.1	40.2
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	32.7	20.5
Property, Plant and Equipment, Net	$ 29.4	$ 19.7
Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	3 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	10 years

Goodwill - Goodwill by Segment

Goodwill - Goodwill by Segment (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Goodwill [Line Items]
Goodwill	$ 47.5	$ 47.5
Commercial Hedging [Member]
Goodwill [Line Items]
Goodwill	30.7	30.7
Global Payments [Member]
Goodwill [Line Items]
Goodwill	6.3	6.3
Physical Commodities Segment [Member]
Goodwill [Line Items]
Goodwill	2.4	2.4
Securities Segment [Member]
Goodwill [Line Items]
Goodwill	$ 8.1	$ 8.1

Intangible Assets - Gross and N

Intangible Assets - Gross and Net Intangible Assets by Major Class (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Trade Names, Gross	$ 1.1
Finite-Lived Computer Software, Gross	22.8	$ 9
Finite-Lived Intangible Assets, Gross	17.8	16.7
Finite-Lived Intangible Assets, Accumulated Amortization	(8.7)	(7.2)
Finite-Lived Intangible Assets, Net	9.1	9.5
Gross Finite and Indefinite-Lived Intangible Assets	17.8	17.8
Finite and Indefinited-Lived Accumulated Amortization and Impairment Charges	(8.7)	(7.2)
Intangible Assets, Net (Excluding Goodwill)	9.1	10.6
Trade Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Trade Names, Gross	1.1	0
Finite-Lived Intangible Assets, Accumulated Amortization	0.6	0
Finite-Lived Intangible Assets, Net	0.5	0
Computer Software, Intangible Asset [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Computer Software, Gross	2.7	2.7
Finite-Lived Intangible Assets, Accumulated Amortization	(2.4)	(2.3)
Finite-Lived Intangible Assets, Net	0.3	0.4
Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Customer Lists, Gross	14	14
Finite-Lived Intangible Assets, Accumulated Amortization	(5.7)	(4.9)
Finite-Lived Intangible Assets, Net	$ 8.3	$ 9.1

Intangible Assets - Indefinite-

Intangible Assets - Indefinite-Lived Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Indefinite-lived Intangible Assets [Line Items]
Gross Finite and Indefinite-Lived Intangible Assets	$ 17.8	$ 17.8
Finite and Indefinited-Lived Accumulated Amortization and Impairment Charges	8.7	7.2
Intangible Assets, Net (Excluding Goodwill)	9.1	10.6
Trade Names [Member]
Indefinite-lived Intangible Assets [Line Items]
Indefinite-Lived Trade Names	0	1.1
Indefinite-lived Intangible Assets, Impairment Losses	$ 0	$ 0

Intangible Assets - Finite-Live

Intangible Assets - Finite-Lived Intangible Assets Future Amortization Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Intangible Assets [Abstract]
Finite-Lived Trade Names, Gross	$ 1.1
Amortization	0.6
Amortization of Intangible Assets	1.6	$ 1.5	$ 1.6
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
Fiscal 2,016	1.6
Fiscal 2,017	1
Fiscal 2,018	1
Fiscal 2,019	0.8
Fiscal 2020 and thereafter	4.7
Finite-Lived Intangible Assets, Net	$ 9.1	$ 9.5

Credit Facilities - Number of C

Credit Facilities - Number of Credit Facilities (Details) $ in Millions	12 Months Ended
	Sep. 30, 2016USD ($)Rate	Jul. 26, 2016USD ($)	May 05, 2015USD ($)
Line of Credit Facility [Line Items]
Number of credit facilities	4
Debt Issuance Cost	$ 1.7
HCO Syndicated line of credit facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage | Rate	0.625%
Debt Issuance Cost	$ 1.8
Line of Credit Facility, Interest Rate at Period End | Rate	5.25%
Line of Credit Facility, Maximum Borrowing Capacity	$ 247
HCO Syndicated line of credit facility [Member] | Eurodollar Rate [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	3.00%
HCO Syndicated line of credit facility [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.00%
INTL FCStone, Ltd [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 25
INTL FCStone, Ltd [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.50%
INTL FCStone Financial Margin line of credit facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage | Rate	0.50%
Line of Credit Facility, Interest Rate at Period End | Rate	5.50%
Line of Credit Facility, Maximum Borrowing Capacity	$ 75	$ 25	$ 50
INTL FCStone Financial Margin line of credit facility [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.00%

Credit Facilities (Details)

Credit Facilities (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Jul. 26, 2016	Sep. 30, 2015	May 05, 2015	Apr. 15, 2015
Line of Credit Facility [Line Items]
Short-term Debt	$ 180		$ 38
Payables to lenders under loans	182.8		41.6
Notes Payable to Bank	2.8		3.6		$ 4
Senior Notes	$ 45.5		45.5
Debt Instrument, Interest Rate, Stated Percentage	8.50%
Debt Instrument, Call Feature, Redemption Price Percentage of Principal	100.00%
Debt Issuance Cost	$ 1.7
Debt and Capital Lease Obligations	$ 228.3		87.1
HCO Syndicated line of credit facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Interest Rate at Period End	5.25%
Line of Credit Facility, Maximum Borrowing Capacity	$ 247
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.625%
Payables to lenders under loans	$ 136.5		28
Debt Issuance Cost	$ 1.8
INTL FCStone Financial Margin line of credit facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Interest Rate at Period End	5.50%
Line of Credit Facility, Maximum Borrowing Capacity	$ 75	$ 25		$ 50
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.50%
Payables to lenders under loans	$ 0		0
INTL FCStone Financial [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	0
Payables to lenders under loans	$ 0		0
FMS Sub-note commodity line of credit facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Interest Rate at Period End	4.25%
Line of Credit Facility, Maximum Borrowing Capacity	$ 100
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.50%
Payables to lenders under loans	$ 43.5		10
INTL FCStone, Ltd [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	25
Payables to lenders under loans	0		$ 0
Main line of credit facilities [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	447
Line of Credit Facility, Current Borrowing Capacity	$ 75
Base Rate [Member] | HCO Syndicated line of credit facility [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.00%
Base Rate [Member] | INTL FCStone Financial Margin line of credit facility [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.00%
Base Rate [Member] | Sterne Agee [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.00%
Base Rate [Member] | INTL FCStone, Ltd [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.50%

Commitments and Contingencies -

Commitments and Contingencies - Contingencies and Litigation (Details) $ in Millions	12 Months Ended
	Sep. 30, 2016USD ($)
Commitments and Contingencies [Abstract]
Excess segregated funds returned	$ 15.5
Excess segregated funds invested	21.9
Pre and Post Transfers of Funds - Sentinel	15.5
Post Transfers of Funds - Sentinel	$ 14.5

Commitments and Contingencies84

Commitments and Contingencies - Contigent Consideration for Acquisitions (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014	Jan. 01, 2015
Business Acquisition, Contingent Consideration [Line Items]
Business Combination, Contingent Consideration, Liability	$ 0.8	$ 3.3
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	(0.4)	1.9	$ (1.8)
G.X. Clarke (INTL FCStone Partners) [Member]
Business Acquisition, Contingent Consideration [Line Items]
Business Combination, Contingent Consideration, Liability	0.8
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	1.5			$ 0.1
Business Combination, Consideration, Including Contingent Consideration	27.5
Contingent Consideration [Member]
Business Acquisition, Contingent Consideration [Line Items]
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	$ 0.4	$ 1.8	$ (2.3)

Commitments and Contingencies85

Commitments and Contingencies - Operating Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Operating Leases [Abstract]
Operating Leases, Rent Expense	$ 9.9	$ 10.1	$ 9.5
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	8.8
Operating Leases, Future Minimum Payments, Due in Two Years	7.1
Operating Leases, Future Minimum Payments, Due in Three Years	6.6
Operating Leases, Future Minimum Payments, Due in Four Years	6.3
Operating Leases, Future Minimum Payments, Due in Five Years	5.5
Operating Leases, Future Minimum Payments, Due Thereafter	10.5
Operating Leases, Future Minimum Payments Due	$ 44.8

Commitments and Contingencies86

Commitments and Contingencies - Purchase Obligations (Details) $ in Millions	Sep. 30, 2016USD ($)
Commitments and Contingencies Disclosure [Abstract]
Purchase Obligation, Due in Next Twelve Months	$ 603.5
Purchase Obligation, Due in Second and Third Year	2.4
Purchase Obligation, Due in Fourth and Fifth Year	1.7
Purchase Obligation, Due after Fifth Year	2
Other Commitment, Due in Next Twelve Months	$ 475.9

Commitments and Contingencies87

Commitments and Contingencies - Self-Insurance (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Commitments and Contingencies [Abstract]
Self Insurance Reserve	$ 1	$ 0.8

Regulatory Requirements and S88

Regulatory Requirements and Subsidiary Dividend Restrictions - Minimum net capital (Details)	Sep. 30, 2016USD ($)
Capital and Other Regulatory Requirements [Abstract]
Minimum Net Capital Required for Broker-Dealer Subsidiary	$ 1,000,000
Minimum Net Capital Required for Entity	$ 0.08

Regulatory Requirements and S89

Regulatory Requirements and Subsidiary Dividend Restrictions - Regulatory Capital Requirements (Details) - USD ($)	Sep. 30, 2016	Sep. 30, 2015
Cash and Securities Segregated under Commodity Exchange Act Regulation		$ 1,880,200,000
Secured funds		85,600,000
Minimum Net Capital Required for Entity	$ 0.08
Cash and Securities Segregated under Commodity Exchange Act Regulation, Amount Required to be Segregated		(1,830,900,000)
Secured Funds Required Under Commodity Exchange Act		$ (65,200,000)
INTL FCStone Financial [Member]
Net Capital	140,800,000
Cash and Securities Segregated under Commodity Exchange Act Regulation	2,177,900,000
Secured funds	107,700,000
Minimum Net Capital Required for Entity	81,700,000
Cash and Securities Segregated under Commodity Exchange Act Regulation, Amount Required to be Segregated	2,126,400,000
Secured Funds Required Under Commodity Exchange Act	(91,300,000)
Sterne Agee Clearing, Inc. [Member]
Net Capital	1,000,000
Minimum Net Capital Required for Entity	100,000
Sterne Agee and Leach, Inc. [Member]
Net Capital	29,000,000
Minimum Net Capital Required for Entity	2,000,000
Sterne Agee Financial Services, Inc. [Member]
Net Capital	3,300,000
Minimum Net Capital Required for Entity	300,000
INTL FCStone, Ltd [Member]
Cash and Securities Segregated under Commodity Exchange Act Regulation	54,800,000
Net Capital under Commodity Exchange Act Computation	136,900,000
Cash and Securities Segregated under Commodity Exchange Act Regulation, Amount Required to be Segregated	49,500,000
Required Net Capital under Commodity Exchange Act	84,900,000
INTL FCStone Europe [Member]
Net Capital under Commodity Exchange Act Computation	136,100,000
Required Net Capital under Commodity Exchange Act	85,000,000
INTL FCStone DTVM Ltda [Member]
Net Capital	2,500,000
Capital Required for Capital Adequacy	500,000
Gainvest S.A. Sociedad Gerente de FCI - Comision Nacional de Valores [Member]
Net Capital	7,700,000
Net Capital under Commodity Exchange Act Computation	3,600,000
Required Net Capital under Commodity Exchange Act	100,000
Capital Required for Capital Adequacy	100,000
INTL Capital S.A. – General Inspector of Justice [Member] [Domain]
Net Capital under Commodity Exchange Act Computation	15,300,000
Required Net Capital under Commodity Exchange Act	12,600,000
INTL CIBSA S.A. - Comision Nacional de Valores [Member]
Net Capital	7,100,000
Net Capital under Commodity Exchange Act Computation	0
Required Net Capital under Commodity Exchange Act	0
Capital Required for Capital Adequacy	$ 1,100,000

Regulatory Requirements and S90

Regulatory Requirements and Subsidiary Dividend Restrictions - Customer Secured Funds (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Cash and Securities Segregated under Commodity Exchange Act [Abstract]
Cash Segregated under Commodity Exchange Act Regulation	$ 383.6	$ 126.9
Securities Segregated under Commodity Exchange Act Regulation	595.4	492.5
Securities Held for Customers in Lieu of Cash, At Banks, Segregated under Commodity Exchange Act Regulation	1.8	0.9
Deposits with and Receivables From Clearing Organizations, Segregated under Commodity Exchange Act Regulation	1,173.9	1,237.8
Securities Held for Customers in Lieu of Cash, Segregated under Commodity Exchange Act Regulation	23.2	22.1
Cash and Securities Segregated under Commodity Exchange Act Regulation		1,880.2
Cash and Securities Segregated under Commodity Exchange Act Regulation, Amount Required to be Segregated		1,830.9
Cash and Securities Segregated under Commodity Exchange Act Regulation, Excess Funds in Segregation	51.5	49.3
Cash and Securities Segregated under Other Regulations [Abstract]
Cash Segregated under Other Regulations	70.5	64.7
Securities Segregated under Other Regulations	0	0
Equities with Futures Commission Merchants Segregated under Other Regulations	3.6	2.6
Amounts Held by Clearing Organizations Segregated under Other Regulations	6.7	0
Amounts Held by Members of Foreign Boards of Trade Segregated under Other Regulations	26.9	18.3
Secured funds		85.6
Secured Funds Required Under Commodity Exchange Act		65.2
Cash and Securities Segregated under Other Regulations	$ 16.4	$ 20.4

Commodity and Other Repurchas91

Commodity and Other Repurchase Agreements (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Sales Repurchase Agreements	$ 1.5	$ 26.7
Obligations outstanding related to commodities sold under repurchase agreements	43.5	10
Securities Sold under Agreements to Repurchase, Fair Value of Collateral	47.2	$ 170.7
Trading Securities Pledged as Collateral	1,037.6
Pledged Financial Instruments, Not Separately Reported, Securities for Repurchase Agreements	108.4
G.X. Clarke (INTL FCStone Partners) [Member]
Fair Value of Securities Received as Collateral that Can be Resold or Repledged	607.3
Fair Value of Securities Received as Collateral that Have Been Resold or Repledged	504.4
Sterne Agee [Member]
Fair Value of Securities Received as Collateral that Can be Resold or Repledged	148.4
Fair Value of Securities Received as Collateral that Have Been Resold or Repledged	$ 22.5

Share-Based Compensation - Shar

Share-Based Compensation - Share-based Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Allocated Share-based Compensation Expense	$ 5.1	$ 3.6	$ 4.3

Share-Based Compensation - Stoc

Share-Based Compensation - Stock Option Plan (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	1,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	754,163	828,665
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 6.40	$ 4.31	$ 4.48
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Stock Options	$ 5.3
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	4 years 9 months 4 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	$ 1.9	$ 3.6	$ 1.8

Share-Based Compensation - St94

Share-Based Compensation - Stock Option Plan Fair Value Weighted-Average Assumptions (Details)	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate	28.00%	28.00%	34.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	0.00%	0.00%	0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	0.83%	0.66%	0.80%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	3 years 22 days	3 years 2 months 19 days	2 years 10 months 17 days

Share-Based Compensation - Sh95

Share-Based Compensation - Share-Based Compensation Table (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	1,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	828,665
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	1,297,984
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	(90,500)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Period Increase (Decrease)	90,500
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	(147,205)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	15,998
Share-based Compensation Arrangement by Share-based Payment Award, Options, Other Increases (Decreases) in Period	(16,498)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period	(8,960)
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	754,163	828,665
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	1,215,821	1,297,984
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	306,520
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 29.55	$ 28.28
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	31.37
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	18.52
Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price	25.23
Share-based Compensation Arrangements by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price	54.23
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	40.58
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Grant Date Fair Value	12.88	12.37
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	6.40	$ 4.31	$ 4.48
Share-based Compensation Arrangement by Share-based Payment Award, Options, Excrecises in Period, Weighted Average Grant Date Fair Value	1.50
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeited in Period, Weighted Average Grant Date Fair Value	5.28
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expired in Period, Weighted Average Grant Date Fair Value	20.04
Share-based Compensation Arrangement by Share-based Payment Award, Options, Excercisable, Weighted Average Grant Date Fair Value	$ 15.09
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	3 years 9 months 18 days	4 years 2 months 27 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	11 months 1 day
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$ 14.1	$ 1.8
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	2.2
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Stock Options	$ 5.3
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	4 years 9 months 4 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	$ 1.9	$ 3.6	$ 1.8

Share-Based Compensation - Opti

Share-Based Compensation - Options by Exercise Price (Details)	12 Months Ended
	Sep. 30, 2016$ / sharesshares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Outstanding Options | shares	1,215,821
Weighted Average Exercise Price	$ 29.55
Weighted Average Remaining Term (in years)	3 years 9 months 18 days
$0 - $5,00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Range Limit	$ 0
Exercise Price Range, Upper Range Limit	$ 5
Number of Outstanding Options | shares	0
$5.00 - $10.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Range Limit	$ 5
Exercise Price Range, Upper Range Limit	$ 10
Number of Outstanding Options | shares	0
$10.00 - $15.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Range Limit	$ 10
Exercise Price Range, Upper Range Limit	$ 15
Number of Outstanding Options | shares	0
$15.00 - $20.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Range Limit	$ 15
Exercise Price Range, Upper Range Limit	$ 20
Number of Outstanding Options | shares	75,325
Weighted Average Exercise Price	$ 18.77
Weighted Average Remaining Term (in years)	1 year
$20.00 - $25.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Range Limit	$ 20
Exercise Price Range, Upper Range Limit	$ 25
Number of Outstanding Options | shares	156,997
Weighted Average Exercise Price	$ 22.07
Weighted Average Remaining Term (in years)	1 year 8 months 23 days
$25.00 - $30.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Range Limit	$ 25
Exercise Price Range, Upper Range Limit	$ 30
Number of Outstanding Options | shares	720,000
Weighted Average Exercise Price	$ 25.91
Weighted Average Remaining Term (in years)	5 years 4 months 17 days
$30.00 - $35.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Range Limit	$ 30
Exercise Price Range, Upper Range Limit	$ 35
Number of Outstanding Options | shares	83,000
Weighted Average Exercise Price	$ 31.37
Weighted Average Remaining Term (in years)	3 years 3 months 11 days
$35.00 - $40.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Range Limit	$ 35
Exercise Price Range, Upper Range Limit	$ 40
Number of Outstanding Options | shares	0
$40.00 - $45.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Range Limit	$ 40
Exercise Price Range, Upper Range Limit	$ 45
Number of Outstanding Options | shares	0
$45.00 - $50.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Range Limit	$ 45
Exercise Price Range, Upper Range Limit	$ 50
Number of Outstanding Options | shares	0
$50.00 - $55.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Range Limit	$ 50
Exercise Price Range, Upper Range Limit	$ 55
Number of Outstanding Options | shares	180,499
Weighted Average Exercise Price	$ 54.23
Weighted Average Remaining Term (in years)	8 months 5 days

Share-Based Compensation - Rest

Share-Based Compensation - Restricted Stock Plan (Details) $ in Millions	12 Months Ended
	Sep. 30, 2016USD ($)shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period	1,500,000
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted	747,782
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized | $	$ 7.1
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition - Restricted Stock	1 year 4 months 21 days

Share-Based Compensation - Re98

Share-Based Compensation - Restricted Stock Plan Table (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted	747,782
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period	1,500,000
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	974,919
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Period Increase (Decrease)	(229,886)
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Forfeitures	2,749
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	747,782	974,919
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	230,043
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	229,886
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	(99,428)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(2,749)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	357,752	230,043
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 20.10
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	31.40
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	19.84
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	21.89
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 27.39	$ 20.10
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Remaining Contractual Terms	1 year 4 months 21 days	2 years 2 months 1 day
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding	$ 13.9	$ 5.7
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 7.1
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition - Restricted Stock	1 year 4 months 21 days

Retirement Plans (Details)

Retirement Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Defined Benefit Plan, Fair Value of Plan Assets	$ 33.7	$ 30.2
Defined Benefit Plan, Benefit Obligation	$ 38.5	$ 37.1
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	3.60%	4.25%
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Projected Benefit Obligation	$ 4.8	$ 6.9
Defined Benefit Plan, Net Periodic Benefit Cost	$ 0.2	0.1	$ 0.1
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets	6.00%
Defined Benefit Plan, Contributions by Employer	$ 1.8	2.2
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year	3
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	2.1
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	2.1
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	2
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	1.9
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	9.3
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 5.3	$ 5.1	$ 4.1
Debt Securities [Member]
Defined Benefit Plan, Actual Plan Asset Allocations	70.00%
Equity Securities [Member]
Defined Benefit Plan, Actual Plan Asset Allocations	30.00%
UK Plan [Member]
Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage	100.00%
UK Plan [Member] | Maximum [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent	10.00%
401k Plan [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent	62.50%
Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage	8.00%
Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage, Two to Three Years	33.00%
Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage, Three to Four Years	66.00%
Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage, All Years	100.00%
401k Plan [Member] | Maximum [Member]
Defined Contribution Plan, Maximum Annual Contribution Per Employee, Percent	80.00%
401k Plan [Member] | Minimum [Member]
Defined Contribution Plan, Maximum Annual Contribution Per Employee, Percent	1.00%

Other Expenses - Other Expenses

Other Expenses - Other Expenses Breakout (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Other Expenses [Abstract]
Accretion Expense	$ 0.4	$ 1.8	$ (2)
General Insurance Expense	2.1	1.7	1.6
Advertising Expense	5.1	2.7	3.1
Technology Services Costs	7.1	4.7	3.8
Supplies and Postage Expense	1.1	1.2	1.1
Clearance Fees	1.3	1.1	1.2
Taxes, Miscellaneous	4.3	3.7	3.9
Other Expenses	8	6.6	5.7
Operating Costs and Expenses	$ 29.4	$ 23.5	$ 18.4

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Income Tax Disclosure [Abstract]
Income tax expense	$ 2.4	$ 6.8	$ 5.5	$ 3.3	$ 8.1	$ 5	$ 5.1	$ 4.2	$ 18	$ 22.4	$ 6.4
Discontinued Operation, Tax Effect of Discontinued Operation									0	0	(0.2)
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax									0	(0.4)	0.1
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized (Gain) Loss Arising During Period, Tax									0.2	(0.8)	(0.5)
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation									(0.8)	(0.5)	0.1
Other Comprehensive Income (Loss), Tax									17.4	20.7	5.9
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense									0
Operating Loss Carryforwards	15.7				12				15.7	12
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	12.4				8.6				12.4	8.6
Deferred Tax Assets, Net of Valuation Allowance, Operating Loss Carryforwards, State and Local	3.3								3.3
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax	1.3								1.3
Deferred Tax Assets, Valuation Allowance	3.6				3.2				3.6	3.2
Valuation Allowance, Deferred Tax Asset, Change in Amount									0.4
Income (Loss) from Continuing Operations before Income Taxes, Domestic									(9.7)	16.5	$ (18.4)
Deferred Tax Liabilities, Gross	4.5								4.5
Deferred Tax Liabilities, Unrealized Gains on Trading Securities	1.3				1				1.3	1
Undistributed Earnings of Foreign Subsidiaries	$ 294.3				$ 227.2				$ 294.3	$ 227.2

Income Taxes - Current and Defe

Income Taxes - Current and Deferred Taxes (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Income Tax Disclosure [Abstract]
Current Federal Tax Expense (Benefit)									$ 1.3	$ 0.8	$ 0.5
Current State and Local Tax Expense (Benefit)									0.8	1.2	0
Current Foreign Tax Expense (Benefit)									16.8	15.4	11.6
Current Income Tax Expense (Benefit)									18.9	17.4	12.1
Deferred Income Tax Expense (Benefit)									(0.8)	5	(5.7)
Other Tax Expense (Benefit)									(0.1)	0	0
Income tax expense	$ 2.4	$ 6.8	$ 5.5	$ 3.3	$ 8.1	$ 5	$ 5.1	$ 4.2	$ 18	$ 22.4	$ 6.4

Income Taxes - US and Internati

Income Taxes - US and International Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Income Tax Disclosure [Abstract]
Income (Loss) from Continuing Operations before Income Taxes, Domestic	$ 4.9	$ 14.5	$ (13)
Income (Loss) from Continuing Operations before Income Taxes, Foreign	67.9	63.7	39
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	$ 72.8	$ 78.2	$ 26

Income Taxes - Effective Rate R

Income Taxes - Effective Rate Reconciliation (Details)	12 Months Ended
	Sep. 30, 2016Rate	Sep. 30, 2015Rate	Sep. 30, 2014Rate
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate	35.00%	35.00%	35.00%
Effective Income Tax Rate Reconciliation, State and Local Income Taxes	1.30%	1.80%	0.00%
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential	(9.30%)	(10.10%)	(14.70%)
Effective Income Tax Rate Reconciliation, Tax Contingencies	0.00%	0.00%	(0.50%)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Meals and Entertainment	0.80%	0.50%	1.90%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Other	0.20%	1.10%	7.00%
Effective Income Tax Rate Reconciliation, Other Adjustments, Percent	(3.00%)	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Deductions, Other	0.30%	(0.10%)	(5.70%)
Effective Income Tax Rate, Continuing Operations	25.00%	28.70%	24.70%
Foreign Tax Authority [Member]
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance	(0.30%)	(0.10%)	1.90%
State and Local Jurisdiction [Member]
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance	0.00%	0.60%	(0.20%)

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets and Liabilites (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Tax Credit Carryforward [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards, Research	$ 0.1
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost	4.3	$ 3.2
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Pensions	1.9	2.7
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Compensation	2	2.3
Deferred Tax Assets, Operating Loss Carryforwards, Foreign	2	2.3
Deferred Tax Assets, Operating Loss Carryforwards, State and Local	4.9	4.3
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	12.4	8.6
Deferred Tax Assets, Intangible Assets	8.3	4.6
Deferred Tax Assets, Equity Method Investments	0	0.2
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts	1.6	2.4
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax	1.4	1
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits	3.3	1.9
Deferred Tax Assets, Other	1.8	1.3
Deferred Tax Assets, Gross	43.9	34.8
Deferred Tax Assets, Valuation Allowance	(3.6)	(3.2)
Deferred Tax Assets, Net of Valuation Allowance	40.3	31.6
Deferred Tax Liabilities, Unrealized Gains on Trading Securities	1.3	1
Deferred Tax Liabilities, Prepaid Expenses	1.9	1.1
Deferred Tax Liabilities, Property, Plant and Equipment	2.6	1.3
Deferred Tax Liabilities, Gross	5.8	3.4
Deferred tax assets, Net	$ 34.5	$ 28.2

Income Taxes - FIN 48 Analysis

Income Taxes - FIN 48 Analysis (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	$ 0
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance beginning of year	0	$ 0	$ 0.1
Gross increases for tax positions related to current year	0	0	0
Gross increases for tax positions related to prior years	0.1	0	0
Gross decreases for tax positions of prior years	0	0	(0.1)
Settlements	0	0	0
Lapse of statute of limitations	0	0	0
Balance end of year	$ 0.1	$ 0	$ 0

Acquisitions and Disposals (Det

Acquisitions and Disposals (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014	Jan. 01, 2015
Business Acquisition [Line Items]
Gross Profit	$ 178.6	$ 175	$ 166.1	$ 151.3	$ 178.7	$ 151.6	$ 156.5	$ 137.5	$ 671	$ 624.3	$ 490.9
Net income	$ 16.8	$ 14.6	$ 14.5	$ 8.8	$ 21.1	$ 12.2	$ 13	$ 9.4	$ 54.7	$ 55.7	$ 19.3
Net basic earnings per share	$ 0.91	$ 0.79	$ 0.77	$ 0.47	$ 1.12	$ 0.64	$ 0.68	$ 0.50	$ 2.94	$ 2.94	$ 1.01
Net diluted earnings per share	$ 0.90	$ 0.78	$ 0.76	$ 0.46	$ 1.09	$ 0.62	$ 0.67	$ 0.49	$ 2.90	$ 2.87	$ 0.98
Business Combination, Consideration Transferred									$ 45
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents	$ 24.9								24.9
Business Combination, Acquired Receivables, Fair Value	151.6								151.6
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets Noncurrent	5.7								5.7
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	4.8								4.8
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	136								136
Gain on acquisition	6.2	$ 0	$ 0	$ 0					6.2	$ 0	$ 0
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual									8.6
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual									0.1
Goodwill	47.5				$ 47.5				47.5	47.5
Deferred consideration payable related to acquisitions									0	$ 5	$ 0
G.X. Clarke (INTL FCStone Partners) [Member]
Business Acquisition [Line Items]
Present Value of Estimated Total Purchase Price	27.5								27.5
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	25.9								25.9
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	1.5								1.5
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	1.5								1.5			$ 0.1
Forward Insight Commodities Acquisition [Member]
Business Acquisition [Line Items]
Present Value of Estimated Total Purchase Price	0.5								0.5
Customer Relationships [Member] | Forward Insight Commodities [Member]
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired									0.5
G.X. Clarke (INTL FCStone Partners) [Member]
Business Acquisition [Line Items]
Escrow Deposit	10								10
Adjustment Escrow	5								5
Indemnity Escrow	5								5
Deferred consideration payable related to acquisitions									5
Business Acquisition, Contingent Consideration, Potential Cash Payment, Year One	0.5								0.5
After-tax net income over year one									5
Business Acquisition, Contingent Consideration, Potential Cash Payment Year Three	$ 1								1
After-tax net income over earn-out period									$ 30

Accumulated Other Comprehens108

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, net	$ (24.6)	$ (17.5)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(7.4)	(4)	$ (4.6)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments, Net of Tax	0.2	1.5	0.8
Net unrealized gain on available-for-sale securities	0	2.7	0.2
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax	0.5	0.3	0.2
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax - AFS securities		(3.3)
Other Comprehensive Income (Loss), Net of Tax	(7.1)	(5.9)	(5.2)
Deferred Tax Liabilities, Accumulated Other Comprehensive Income - AFS Securities		2
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, net	(20.1)	(12.7)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(7.4)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax	0
Other Comprehensive Income (Loss), Net of Tax	(7.4)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, net	(4.5)	(4.8)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments, Net of Tax	(0.2)
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax	0.5
Other Comprehensive Income (Loss), Net of Tax	0.3
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, net	(24.6)	(17.5)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(7.6)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0.5
Other Comprehensive Income (Loss), Net of Tax	$ (7.1)	$ (5.9)	$ (5.2)

Discontinued Operations (Detail

Discontinued Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Discontinued Operations and Disposal Groups [Abstract]
Disposal Group, Including Discontinued Operation, Revenue	$ 0	$ 0	$ 40.9
Disposal Group, Including Discontinued Operation, Costs of Goods Sold	0	0	40.2
Disposal Group, Including Discontinued Operation, Gross Profit (Loss)	0	0	0.7
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax	0	0	(0.5)
Discontinued Operation, Tax Effect of Discontinued Operation	0	0	0.2
Loss from discontinued operations, net of tax	$ 0	$ 0	$ (0.3)

Quarterly Financial Informat110

Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Quarterly Financial Information Disclosure [Abstract]
Total revenues	$ 2,777.6	$ 4,868.5	$ 3,708.9	$ 3,399.9	$ 2,628.4	$ 3,995.1	$ 14,442	$ 13,627.7	$ 14,754.9	$ 34,693.2	$ 34,022.4
Cost of sales of physical commodities	2,599	4,693.5	3,542.8	3,248.6	2,449.7	3,843.5	14,285.5	13,490.2	14,083.9	34,068.9	33,531.5
Operating revenues	178.6	175	166.1	151.3	178.7	151.6	156.5	137.5	671	624.3	490.9
Transaction-based clearing expenses	32	35.2	32.9	29.8	31.3	30.2	31.8	29.4	129.9	122.7	108.5
Introducing broker commissions	28.1	14.8	13.2	12.8	15.1	13.1	12.3	12.2	68.9	52.7	49.9
Interest expense	7.5	7.7	7.1	6	5	4.9	4.5	2.7	28.3	17.1	10.5
Net operating revenues	111	117.3	112.9	102.7	127.3	103.4	107.9	93.2	443.9	431.8	322
Compensation and other expenses	98	95.9	92.9	90.6	98.1	86.2	89.8	79.6	377.4	353.7	296
Gain on acquisition	6.2	0	0	0					6.2	0	0
Income before tax	19.2	21.4	20	12.1	29.2	17.2	18.1	13.6	72.7	78.1	26
Income tax expense	2.4	6.8	5.5	3.3	8.1	5	5.1	4.2	18	22.4	6.4
Net income	$ 16.8	$ 14.6	$ 14.5	$ 8.8	$ 21.1	$ 12.2	$ 13	$ 9.4	$ 54.7	$ 55.7	$ 19.3
Net basic earnings per share	$ 0.91	$ 0.79	$ 0.77	$ 0.47	$ 1.12	$ 0.64	$ 0.68	$ 0.50	$ 2.94	$ 2.94	$ 1.01
Net diluted earnings per share	$ 0.90	$ 0.78	$ 0.76	$ 0.46	$ 1.09	$ 0.62	$ 0.67	$ 0.49	$ 2.90	$ 2.87	$ 0.98

Segment and Geographic Infor111

Segment and Geographic Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Revenues	$ 2,777.6	$ 4,868.5	$ 3,708.9	$ 3,399.9	$ 2,628.4	$ 3,995.1	$ 14,442	$ 13,627.7	$ 14,754.9	$ 34,693.2	$ 34,022.4
Operating revenues	178.6	175	166.1	151.3	178.7	151.6	156.5	137.5	671	624.3	490.9
Revenues, Net of Interest Expense	111	117.3	112.9	102.7	127.3	103.4	107.9	93.2	443.9	431.8	322
Net Segment Contribution									347	320.6	249.2
Segment Income									206	188.1	128.8
Costs not allocated to operating segments									133.3	110	102.8
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	19.2	$ 21.4	$ 20	$ 12.1	29.2	$ 17.2	$ 18.1	$ 13.6	72.7	78.1	26
Assets	5,951.3				5,070				5,951.3	5,070	3,039.7
Commercial Hedging [Member]
Segment Reporting Information [Line Items]
Revenues									236.1	262.4	224
Operating revenues									236.1	262.4	224
Revenues, Net of Interest Expense									188.2	214.7	180.5
Net Segment Contribution									134.4	151.7	132.6
Segment Income									68.7	85.6	67.3
Assets	1,637.5				1,548.1				1,637.5	1,548.1	1,400.9
Global Payments [Member]
Segment Reporting Information [Line Items]
Revenues									73.2	77.1	55.4
Operating revenues									73.2	77.1	55.4
Revenues, Net of Interest Expense									65.3	68.5	48.2
Net Segment Contribution									52.2	54.5	37.6
Segment Income									39.8	43.3	28.3
Assets	191.4				207.3				191.4	207.3	51.9
Securities Segment [Member]
Segment Reporting Information [Line Items]
Revenues									175.2	129.8	80.3
Operating revenues									175.2	129.8	80.3
Revenues, Net of Interest Expense									121.9	88.6	54.6
Net Segment Contribution									97.5	67.4	40.9
Segment Income									69.4	40.5	21
Assets	2,130.7				1,861				2,130.7	1,861	235.5
Physical Commodities Segment [Member]
Segment Reporting Information [Line Items]
Revenues									14,120.5	34,092	33,552.1
Operating revenues									36.6	23.1	20.6
Revenues, Net of Interest Expense									31.5	21.2	17.9
Net Segment Contribution									23.4	16.9	14.1
Segment Income									13.3	5.8	5.9
Assets	258				190.9				258	190.9	116.8
Clearing and Execution Services Segment [Member]
Segment Reporting Information [Line Items]
Revenues									151.1	123.4	113.7
Operating revenues									151.1	123.4	113.7
Revenues, Net of Interest Expense									48.8	38.3	29.7
Net Segment Contribution									39.5	30.1	24
Segment Income									14.8	12.9	6.3
Assets	1,617.4				1,163.8				1,617.4	1,163.8	1,136.2
Corporate [Member]
Segment Reporting Information [Line Items]
Revenues									(1.2)	8.5	(3.1)
Operating revenues									(1.2)	8.5	(3.1)
Revenues, Net of Interest Expense									(11.8)	0.5	(8.9)
Assets	$ 116.3				$ 98.9				$ 116.3	$ 98.9	$ 98.4

Segment and Geographic Infor112

Segment and Geographic Information - Total Revenues by Geographic Location (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Revenues	$ 2,777.6	$ 4,868.5	$ 3,708.9	$ 3,399.9	$ 2,628.4	$ 3,995.1	$ 14,442	$ 13,627.7	$ 14,754.9	$ 34,693.2	$ 34,022.4
Gross Profit	178.6	$ 175	$ 166.1	$ 151.3	178.7	$ 151.6	$ 156.5	$ 137.5	671	624.3	490.9
Long-Lived Assets	29.4				19.7				29.4	19.7	15.9
UNITED STATES
Revenues									817.1	25,959	19,055.3
Gross Profit									457	424.3	330.4
Long-Lived Assets	23.3				13.8				23.3	13.8	8.5
Europe [Member]
Revenues									463.5	121.2	86
Gross Profit									120.2	125	86
Long-Lived Assets	4.8				4				4.8	4	5
South America [Member]
Revenues									64.8	49	53.2
Gross Profit									64.8	49	53.2
Long-Lived Assets	1.2				1.7				1.2	1.7	2
Asia [Member]
Revenues									13,405.1	8,560	14,822.4
Gross Profit									24.6	21.9	15.8
Long-Lived Assets	0.1				0.2				0.1	0.2	0.3
Other (geographic location) [Member]
Revenues									4.4	4	5.5
Gross Profit									4.4	4.1	5.5
Long-Lived Assets	$ 0				$ 0				$ 0	$ 0	$ 0.1

Condensed Parent Only Financ113

Condensed Parent Only Financial Statements - Balance Sheet (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Cash and cash equivalents	$ 316.2	$ 268.1	$ 231.3	$ 156.1
Deposits and receivables from broker-dealers, clearing organizations and counterparties	237	277.6
Income taxes receivable	1.1	10.6
Financial instruments owned, at fair value	1,606.1	1,421.9
Deferred tax assets, Net	34.5	28.2
Property and equipment, net	29.4	19.7
Total assets	5,951.3	5,070	3,039.7
Liabilities:
Accounts payable and other accrued liabilities	161.3	144.8
Payables to Customers	2,854.2	2,593.5
Payables to lenders under loans	182.8	41.6
Senior unsecured notes	45.5	45.5
Financial Instruments Sold, Not yet Purchased, at Fair Value	839.4	568.3
Total liabilities	5,517.5	4,672.9
INTL FCStone Inc. (Parent Company Only) stockholders’ equity:
Common stock, $0.01 par value. Authorized 30,000,000 shares; 20,557,175 issued and 18,435,218 outstanding at September 30, 2016 and 20,184,556 issued and 18,812,803 outstanding at September 30, 2015	0.2	0.2
Common stock in treasury, at cost - 2,121,957 shares at September 30, 2016 and 1,371,753 shares at September 30, 2015	(46.3)	(26.8)
Additional Paid in Capital	249.4	240.8
Retained earnings	255.1	200.4
Total INTL FCStone Inc. (Parent Company Only) stockholders’ equity	433.8	397.1
Total liabilities and stockholders' equity	5,951.3	5,070
Parent Company [Member]
Cash and cash equivalents	1.3	2.5	$ 3	$ 3.1
Deposits and receivables from broker-dealers, clearing organizations and counterparties	2.9	0
Receivables from subsidiaries	3.6	0.4
Notes receivable, net	6.9	46.4
Income taxes receivable	14	24.3
Investment in subsidiaries	316.3	286
Financial instruments owned, at fair value	1.3	3
Deferred tax assets, Net	15.7	12
Property and equipment, net	12.7	9.2
Other assets	17.2	13.1
Total assets	391.9	396.9
Liabilities:
Accounts payable and other accrued liabilities	27.7	29.3
Payables to Customers	4.6	30.7
Payables to lenders under loans	139.3	31.6
Payable to subsidiaries, net	17.1	123.7
Senior unsecured notes	45.5	45.5
Financial Instruments Sold, Not yet Purchased, at Fair Value	35.9	0
Total liabilities	270.1	260.8
INTL FCStone Inc. (Parent Company Only) stockholders’ equity:
Preferred stock, $.01 par value. Authorized 1,000,000 shares; no shares issued or outstanding	0	0
Common stock, $0.01 par value. Authorized 30,000,000 shares; 20,557,175 issued and 18,435,218 outstanding at September 30, 2016 and 20,184,556 issued and 18,812,803 outstanding at September 30, 2015	0.2	0.2
Common stock in treasury, at cost - 2,121,957 shares at September 30, 2016 and 1,371,753 shares at September 30, 2015	(46.3)	(26.8)
Additional Paid in Capital	249.4	240.8
Retained earnings	(81.5)	(78.1)
Total INTL FCStone Inc. (Parent Company Only) stockholders’ equity	121.8	136.1
Total liabilities and stockholders' equity	391.9	396.9
Adjustment to Investment in Subs for Equity Method Accounting	$ 336.6	$ 278.5

Condensed Parent Only Financ114

Condensed Parent Only Financial Statements - Balance Sheet (Parentheticals) (Details) - $ / shares	Sep. 30, 2016	Sep. 30, 2015
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Preferred stock - par value	$ 0.01	$ 0.01
Preferred stock - authorized	1,000,000	1,000,000
Preferred stock - issued	0	0
Preferred stock - outstanding	0	0
Common stock - par value	$ 0.01	$ 0.01
Common stock - authorized	30,000,000	30,000,000
Common stock - issued	20,557,175	20,184,556
Common stock - outstanding	18,435,218	18,812,803
Treasury stock - shares	2,121,957	1,371,753

Condensed Parent Only Financ115

Condensed Parent Only Financial Statements - Income Statement (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Condensed Financial Statements, Captions [Line Items]
Trading gains, net									$ 321.2	$ 328.6	$ 244.5
Consulting fees									224.3	192.5	180.7
Interest income									55.2	39.4	8
Dividend income from subsidiaries									31	6	0
Operating revenues	$ 178.6	$ 175	$ 166.1	$ 151.3	$ 178.7	$ 151.6	$ 156.5	$ 137.5	671	624.3	490.9
Interest expense	7.5	7.7	7.1	6	5	4.9	4.5	2.7	28.3	17.1	10.5
Net operating revenues	111	117.3	112.9	102.7	127.3	103.4	107.9	93.2	443.9	431.8	322
Non-interest expenses:
Compensation and benefits									263.9	251.1	201.9
Clearing and related expenses	32	35.2	32.9	29.8	31.3	30.2	31.8	29.4	129.9	122.7	108.5
Introducing broker commissions	28.1	14.8	13.2	12.8	15.1	13.1	12.3	12.2	68.9	52.7	49.9
Communication and data services									32.7	28.1	25.8
Occupancy and equipment rental									13.3	13.5	12.3
Professional fees									14	12.5	14.9
Travel and business development									11.5	10.5	9.9
Depreciation and amortization									8.2	7.2	7.3
Bad debts and impairments									4.4	7.3	5.5
Other									29.4	23.5	18.4
Total non-interest expenses	98	95.9	92.9	90.6	98.1	86.2	89.8	79.6	377.4	353.7	296
Gain on acquisition	6.2	0	0	0					6.2	0	0
Loss from continuing operations, before tax	(19.2)	(21.4)	(20)	(12.1)	(29.2)	(17.2)	(18.1)	(13.6)	(72.7)	(78.1)	(26)
Income tax benefit	$ (2.4)	$ (6.8)	$ (5.5)	$ (3.3)	$ (8.1)	$ (5)	$ (5.1)	$ (4.2)	(18)	(22.4)	(6.4)
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Management fees from affiliates									30.1	26.6	9.5
Trading gains, net									0.7	3.2	0
Consulting fees									2.2	2.1	1.6
Interest income									1.8	4.6	4.3
Operating revenues									65.8	42.5	15.4
Interest expense									13.4	12.7	10.6
Net operating revenues									52.4	29.8	4.8
Non-interest expenses:
Compensation and benefits									52.8	43.5	29.8
Clearing and related expenses									1.7	1.2	0.3
Introducing broker commissions									0.6	0.5	0.3
Communication and data services									6.7	5.7	1.3
Occupancy and equipment rental									2.8	2.1	2
Professional fees									4.8	4.6	5
Travel and business development									1.7	1.4	1.1
Depreciation and amortization									2.5	1.8	1.8
Bad debts and impairments									0.2	1.6	0.1
Management services fee to affiliates									1.2	4.3	2.9
Other									11.7	10.2	3.5
Total non-interest expenses									86.7	76.9	48.1
Gain on acquisition									6.2	0	0
Loss from continuing operations, before tax									28.1	47.1	43.3
Income tax benefit									24.7	19.4	17.1
Net loss									(3.4)	(27.7)	(26.2)
Adjustment to Investment in Subs for Equity Method Accounting									$ 58.1	$ 83.4	$ 45.5

Condensed Parent Only Financ116

Condensed Parent Only Financial Statements - Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended				12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Condensed Financial Statements, Captions [Line Items]
Depreciation and amortization					$ 8.2	$ 7.2	$ 7.3
Bad debts and impairments					4.4	7.3	5.5
Deferred income taxes					(0.8)	5	(5.7)
Amortization of debt issuance costs and debt discount					1.1	0.9	1
Amortization of share-based compensation expense					5.1	3.6	4.3
Gain on acquisition	$ (6.2)	$ 0	$ 0	$ 0	(6.2)	0	0
Deposits and receivables from broker-dealers, clearing organizations, and counterparties					135.7	(150.2)	1.1
Receivables from subsidiaries, net					(3.1)	0	0
Notes receivable, net					59.5	(14.5)	(27.9)
Income taxes receivable					8.2	0	4.2
Financial instruments owned, at fair value					(192.9)	(565)	(42.6)
Other assets					(17.4)	(16.2)	0.1
Accounts payable and other accrued liabilities					7.5	23.2	1.9
Payable to customers					172.2	332.1	191.5
Financial instruments sold, not yet purchased, at fair value					273.9	177.5	84.1
Net cash (used in) provided by operating activities					(27.8)	37.9	132.6
Purchase of property and equipment					(15.4)	(9.1)	(4.3)
Net cash used in investing activities					(35.5)	(15.5)	(4.3)
Payable to lenders under loans					142	15.5	(38.5)
Proceeds from notes payable					0	4	0
Payments of notes payable					(0.8)	(0.4)	0
Payments related to earn-outs on acquisitions					(2.9)	(2.2)	(1.6)
Share repurchase					(19.5)	(4.7)	(9.7)
Debt issuance costs					(2.1)	(0.2)	(0.3)
Exercise of stock options					3.5	2.5	1.4
Income tax benefit on stock options and awards					0.8	0.5	(0.1)
Net cash provided by (used in) financing activities					121	15	(48.8)
Net (decrease) increase in cash and cash equivalents					48.1	36.8	75.2
Cash and cash equivalents at beginning of period				268.1	268.1	231.3	156.1
Cash and cash equivalents at end of period	316.2				316.2	268.1	231.3
Cash paid for interest					26	15.8	9.6
Income taxes (received) paid, net of cash refunds					8.5	15.3	3
Additional consideration payable related to acquisitions					(0.4)	1.9	(1.8)
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net loss					(3.4)	(27.7)	(26.2)
Depreciation and amortization					2.5	1.8	1.8
Bad debts and impairments					0.2	1.6	0.1
Deferred income taxes					(3.3)	4.6	(9.6)
Amortization of debt issuance costs and debt discount					1	0.8	0.8
Amortization of share-based compensation expense					5.1	3.6	4.3
Gain on acquisition					(6.2)	0	0
Deposits and receivables from broker-dealers, clearing organizations, and counterparties					2.8	0	0
Due to/from subsidiaries					(86.6)	33.2	84.6
Notes receivable, net					39.1	(7.8)	(12.8)
Income taxes receivable					10.3	(11.4)	4.6
Financial instruments owned, at fair value					1.7	(3)	0
Other assets					0.3	(3.9)	(1.1)
Accounts payable and other accrued liabilities					0.4	12.6	(1.1)
Payable to customers					(26.1)	4.9	7.1
Financial instruments sold, not yet purchased, at fair value					35.9	0	(0.6)
Net cash (used in) provided by operating activities					(35)	9.3	51.9
Capital contribution in affiliates					(48.4)	(22.4)	(0.5)
Capital withdrawals from affiliates					0	7.8	0
Purchase of property and equipment					(5.5)	(7.8)	(1.8)
Net cash used in investing activities					(53.9)	(22.4)	(2.3)
Payable to lenders under loans					108.5	13	(40)
Payments related to earn-outs on acquisitions					(2.9)	(2.2)	(1.1)
Share repurchase					(19.5)	(4.7)	(9.7)
Debt issuance costs					(1.9)	(0.1)	(0.2)
Exercise of stock options					3.5	2.5	1.4
Income tax benefit on stock options and awards					0.8	0.5	(0.1)
Net cash provided by (used in) financing activities					87.7	12.6	(49.7)
Net (decrease) increase in cash and cash equivalents					(1.2)	(0.5)	(0.1)
Cash and cash equivalents at beginning of period				$ 2.5	2.5	3	3.1
Cash and cash equivalents at end of period	$ 1.3				1.3	2.5	3
Cash paid for interest					9	11.9	6.9
Income taxes (received) paid, net of cash refunds					(33.8)	(12.9)	(5.3)
Additional consideration payable related to acquisitions					$ (0.4)	$ 1.9	$ (3)

Subsequent Events Subsequent117

Subsequent Events Subsequent Events - Redemption of Senior Notes (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Subsequent Events [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	8.50%
Senior Notes	$ 45.5	$ 45.5
Debt Instrument, Call Feature, Redemption Price Percentage of Principal	100.00%

Subsequent Events Subsequent118

Subsequent Events Subsequent Events - Acquisitions (Details) $ in Millions	12 Months Ended
	Sep. 30, 2016USD ($)
Subsequent Events [Abstract]
Payments to Acquire Businesses, Gross	$ 6