Global Brokerage (GLBR) 10-K 17 Mar 14 2013 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2013	Mar. 12, 2014	Jun. 28, 2013
Document Information [Line Items]	'	'	'
Document Type	'10-K	'	'
Amendment Flag	'false	'	'
Document Period End Date	31-Dec-13	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'
Trading Symbol	'FXCM	'	'
Entity Registrant Name	'FXCM Inc.	'	'
Entity Central Index Key	'0001499912	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Well-known Seasoned Issuer	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Filer Category	'Accelerated Filer	'	'
Entity Common Stock, Shares Outstanding	'	45,792,292	'
Entity Public Float	'	'	$623,789,933

Consolidated_Statements_of_Fin

Consolidated Statements of Financial Condition (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current assets	'	'
Cash and cash equivalents	$365,245	$272,332
Cash and cash equivalents, held for customers	1,190,880	1,190,762
Due from brokers	5,450	8,040
Accounts receivable, net	9,953	6,336
Deferred tax asset	11,910	10,598
Notes receivable	5,992	0
Tax receivable	3,861	6,003
Total current assets	1,593,291	1,494,071
Deferred tax asset	166,576	117,221
Office, communication and computer equipment, net	49,165	50,316
Goodwill	307,936	285,654
Other intangible assets, net	76,713	97,792
Notes receivable	5,950	0
Other assets	24,316	20,116
Total assets	2,223,947	2,065,170
Current liabilities	'	'
Customer account liabilities	1,190,880	1,190,762
Accounts payable and accrued expenses	69,697	52,635
Credit agreement	0	85,000
Notes payable	9,800	22,867
Due to brokers	8,652	14,494
Deferred tax liability	0	7,100
Due to related parties pursuant to tax receivable agreement	18,588	13,569
Total current liabilities	1,297,617	1,386,427
Deferred tax liability	3,687	12,351
Due to related parties pursuant to tax receivable agreement	131,670	87,271
Senior convertible notes	146,303	0
Other liabilities	9,289	4,206
Total liabilities	1,588,566	1,490,255
Commitments and Contingencies	'	'
Stockholders' Equity	'	'
Additional paid-in-capital	245,426	171,390
Retained earnings	16,352	11,122
Accumulated other comprehensive income	-5,344	-1,301
Total stockholders’ equity, FXCM Inc.	256,882	181,559
Non-controlling interests	378,499	393,356
Total stockholders’ equity	635,381	574,915
Total liabilities and stockholders’ equity	2,223,947	2,065,170
Class A common stock	'	'
Stockholders' Equity	'	'
Common stock	447	347
Class B common stock	'	'
Stockholders' Equity	'	'
Common stock	$1	$1

Consolidated_Statements_of_Fin1

Consolidated Statements of Financial Condition (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Class A common stock	'	'
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	3,000,000,000	3,000,000,000
Common stock, shares issued	44,664,884	34,683,599
Common stock, shares outstanding	44,664,884	34,683,599
Class B common stock	'	'
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	1,000,000	1,000,000
Common stock, shares issued	41	43
Common stock, shares outstanding	41	43

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	12 Months Ended
Share data in Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues	'	'	'
Retail trading revenue	$365,285,000	$339,685,000	$363,774,000
Institutional trading revenue	103,994,000	62,033,000	28,908,000
Trading revenue	469,279,000	401,718,000	392,682,000
Interest income	2,614,000	3,571,000	3,644,000
Brokerage interest expense	-258,000	-277,000	-329,000
Net interest revenue	2,356,000	3,294,000	3,315,000
Other income	17,953,000	12,303,000	19,581,000
Total net revenues	489,588,000	417,315,000	415,578,000
Operating Expenses	'	'	'
Compensation and benefits	105,470,000	105,779,000	95,086,000
Allocation of income to Lucid members for services provided	21,290,000	0	0
Total compensation and benefits	126,760,000	105,779,000	95,086,000
Referring broker fees	84,231,000	76,585,000	92,832,000
Advertising and marketing	27,091,000	30,860,000	34,897,000
Communication and technology	38,441,000	37,113,000	31,869,000
Trading costs, prime brokerage and clearing fees	30,821,000	16,935,000	8,167,000
General and administrative	68,230,000	63,043,000	63,077,000
Depreciation and amortization	53,729,000	36,773,000	20,053,000
Total operating expenses	429,303,000	367,088,000	345,981,000
Total operating income	60,285,000	50,227,000	69,597,000
Other Expense	'	'	'
Loss on equity method investments, net	752,000	0	0
Interest on borrowings	7,673,000	2,763,000	0
Income before income taxes	51,860,000	47,464,000	69,597,000
Income tax provision	17,024,000	8,986,000	10,816,000
Net income	34,836,000	38,478,000	58,781,000
Net income attributable to FXCM Inc.	14,832,000	8,958,000	12,736,000
Weighted average shares of Class A common stock outstanding:	'	'	'
Basic (in shares)	32,789	24,086	16,567
Diluted (in shares)	33,957	24,086	16,567
Net income per share attributable to stockholders of Class A common stock of FXCM Inc.:	'	'	'
Basic (in dollars per share)	$0.45	$0.37	$0.77
Diluted (in dollars per share)	$0.44	$0.37	$0.77
Dividends declared per common share (in dollars per share)	$0.24	$0.24	$0.24
Other non-controlling interests	'	'	'
Other Expense	'	'	'
Net income (loss) attributable to non-controlling interest	-4,846,000	6,389,000	0
FXCM Holdings, LLC	'	'	'
Other Expense	'	'	'
Net income (loss) attributable to non-controlling interest	$24,850,000	$23,131,000	$46,045,000

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net income	$34,836	$38,478	$58,781
Other comprehensive income	'	'	'
Foreign currency translation gain (loss)	-9,678	-3,414	57
Income tax expense (benefit)	-108	12	-3
Other comprehensive income (loss), net of tax	-9,570	-3,426	60
Comprehensive income	25,266	35,052	58,841
Comprehensive income attributable to FXCM Inc.	10,789	7,515	12,826
Other non-controlling interests	'	'	'
Other comprehensive income	'	'	'
Comprehensive income (loss) attributable to non-controlling interest	-4,846	6,389	0
FXCM Holdings, LLC	'	'	'
Other comprehensive income	'	'	'
Comprehensive income (loss) attributable to non-controlling interest	$19,323	$21,148	$46,015

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders' Equity/Members' Capital (USD $)	Total	Non-controlling Interest	Retained Earnings	Accumulated Other Comprehensive Income	Additional Paid-in Capital	Common Stock - Class B	Class A common stock
In Thousands, except Share data, unless otherwise specified
Balance as of beginning of period at Dec. 31, 2010	$268,007	$165,787	$146	$52	$101,848	$1	$173
Balance as of beginning of period (in shares) at Dec. 31, 2010	'	'	'	'	'	100	17,319,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'
Net income	58,781	46,045	12,736	'	'	'	'
Other comprehensive income (loss), net of tax	60	-30	'	90	'	'	'
Comprehensive income	58,841	46,015	12,736	90	'	'	'
Repurchase of class A common stock	-26,357	'	'	'	-26,333	'	-24
Repurchase of class A common stock (in shares)	'	'	'	'	'	'	-2,419,609
Equity based compensation	10,637	'	'	'	10,637	'	'
Dividends on class A common stock	-3,905	'	-3,905	'	'	'	'
Other Initial Public Offering costs	-142	-142	'	'	'	'	'
Contributions	16,263	16,263	'	'	'	'	'
Distributions	-29,911	-29,911	'	'	'	'	'
Balance as of end of period at Dec. 31, 2011	293,433	198,012	8,977	142	86,152	1	149
Balance as of end of period (in shares) at Dec. 31, 2011	'	'	'	'	'	100	14,899,391
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'
Net income	38,478	29,520	8,958	'	'	'	'
Other comprehensive income (loss), net of tax	-3,426	-1,983	'	-1,443	'	'	'
Comprehensive income	35,052	27,537	8,958	-1,443	'	'	'
Repurchase of class A common stock	-7,475	-2,618	'	'	-4,849	'	-8
Repurchase of class A common stock (in shares)	'	'	'	'	'	'	-750,125
Equity based compensation	24,354	12,918	'	'	11,428	'	8
Equity based compensation (in shares)	'	'	'	'	'	'	782,015
Dividends on class A common stock	-6,813	'	-6,813	'	'	'	'
Exchange of Holdings Units to Class A common stock (see Note 15)	0	-17,759	'	'	17,651	'	108
Exchange of Holdings units to Class A common stock (see Note 15) (in shares)	'	'	'	'	'	-57	10,752,318
Effects of Tax Receivable Agreement	5,120	'	'	'	5,120	'	'
Settlement of receivable balance with related party (see Note 15)	-3,979	-3,205	'	'	-774	'	'
Stock issuances, Lucid acquisition (see Note 5)	21,491	7,851	'	'	13,622	'	18
Stock issuances, Lucid acquisition (see Note 5) (in shares)	'	'	'	'	'	'	1,800,000
Contingently issuable shares, Lucid acquisition (see Note 5)	67,915	24,803	'	'	43,040	'	72
Contingently issuable shares, Lucid acquisition (see Note 5) (in shares)	'	'	'	'	'	'	7,200,000
Contributions	578	578	'	'	'	'	'
Distributions	-14,926	-14,926	'	'	'	'	'
Non-controlling interest	160,165	160,165	'	'	'	'	'
Balance as of end of period at Dec. 31, 2012	574,915	393,356	11,122	-1,301	171,390	1	347
Balance as of end of period (in shares) at Dec. 31, 2012	'	'	'	'	'	43	34,683,599
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'
Net income	34,836	20,004	14,832	'	'	'	'
Other comprehensive income (loss), net of tax	-9,570	-5,527	'	-4,043	'	'	'
Comprehensive income	25,266	14,477	14,832	-4,043	'	'	'
Repurchase of class A common stock	-28,080	-9,270	'	'	-18,792	'	-18
Repurchase of class A common stock (in shares)	'	'	'	'	'	'	-1,815,800
Equity based compensation	15,299	8,668	'	'	6,631	'	'
Dividends on class A common stock	-9,602	'	-9,602	'	'	'	'
Exchange of Holdings Units to Class A common stock (see Note 15)	0	-53,500	'	'	53,399	'	101
Assignment of permitted transferees	0	'	'	'	'	'	'
Assignment of permitted transferees (in shares)	'	'	'	'	'	2	'
Stock options exercised	22,499	7,777	'	'	14,705	'	17
Stock options exercised (in shares)	1,702,714	'	'	'	'	'	1,702,714
Exchange of Holdings units to Class A common stock (see Note 15) (in shares)	'	'	'	'	'	-4	10,094,371
Effects of Tax Receivable Agreement	9,441	'	'	'	9,441	'	'
Equity component of Convertible Note issuance	29,101	15,512	'	'	13,589	'	'
Sale of warrants	18,571	9,899	'	'	8,672	'	'
Purchase of Convertible Note hedges	-29,101	-15,512	'	'	-13,589	'	'
Contributions	5,650	5,650	'	'	'	'	'
Non-controlling interest- Other Adj	0	20	'	'	-20	'	'
Distributions	-14,147	-14,147	'	'	'	'	'
Non-controlling interest	15,569	15,569	'	'	'	'	'
Balance as of end of period at Dec. 31, 2013	$635,381	$378,499	$16,352	($5,344)	$245,426	$1	$447
Balance as of end of period (in shares) at Dec. 31, 2013	'	'	'	'	'	41	44,664,884

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash Flows From Operating Activities	'	'	'
Net income	$34,836	$38,478	$58,781
Adjustments to reconcile net income to net cash provided by operating activities	'	'	'
Depreciation and amortization	53,729	36,773	20,053
Equity-based compensation	13,959	22,979	9,535
Deferred tax expense (benefit)	11,442	7,170	-74
Deferred revenue	0	0	-6,000
Adjustment to follow-on payment for business acquisition	-6,959	0	0
Loss on disposal of fixed assets	126	773	320
Amortization of deferred bond discount	2,904	0	0
Amortization of deferred financing cost	1,263	304	0
Loss on equity method investments, net	752	0	0
Gain on settlement of receivables from related parties	0	-1,436	0
Bad debt	0	0	1,250
Due to related parties pursuant to tax receivable agreement	1,209	0	-3,314
Changes in operating assets and liabilities	'	'	'
Cash and cash equivalents, held for customers	1,390	-142,463	-116,276
Due from brokers	2,590	-6,427	2,739
Accounts receivable, net	-3,577	13,178	765
Tax receivable, net	2,142	-3,987	177
Other assets	1,521	5,172	-3,256
Customer account liabilities	118	143,779	118,981
Accounts payable and accrued expenses	15,997	-11,341	4,572
Other liabilities	1,410	0	0
Payments for tax receivable agreement	-4,079	0	0
Due to brokers	-5,842	999	-4,304
Foreign currency remeasurement loss	-1,359	-1,817	0
Net cash provided by operating activities	123,572	102,134	83,949
Cash Flows From Investing Activities	'	'	'
Acquisition of business, net of cash acquired	-32,312	-36,555	-12,787
Payment for equity investment	-3,000	-4,000	-1,319
Purchases of intangible assets	-50	-134	-1,456
Purchase of notes receivable	-11,942	0	0
Purchase of office, communication and computer equipment, net	-23,416	-27,263	-30,041
Net cash used in investing activities	-70,720	-67,952	-45,603
Cash Flows From Financing Activities	'	'	'
Payment for IPO	0	0	-142
Members’ distributions	-14,147	-14,926	-29,911
Members' contributions	5,650	578	16,263
Dividends paid	-9,602	-6,813	-3,905
Proceeds from exercise of stock options	22,499	0	0
Common stock repurchases	-28,080	-7,475	-26,357
Proceeds from issuance of senior convertibles notes, net	166,453	0	0
Purchase of convertible note hedges	-29,101	0	0
Proceeds from sale of warrants	18,571	0	0
Borrowings under the credit agreement	10,000	130,000	0
Payments on borrowings under the credit agreement	-95,000	-45,000	0
Net cash provided by (used in) financing activities	47,243	56,364	-44,052
Effect of foreign currency exchange rate changes on cash and cash equivalents	-7,182	-2,935	-2,903
Net increase (decrease) in cash and cash equivalents	92,913	87,611	-8,609
Cash and cash equivalents	'	'	'
Beginning of year	272,332	184,721	193,330
End of year	365,245	272,332	184,721
Supplemental disclosures of cash flow activities	'	'	'
Net cash paid for taxes	6,936	12,617	4,117
Net cash paid for interest	3,449	2,334	0
Supplemental disclosure of non-cash investing activities	'	'	'
Exchange of Holding Units for shares of Class A common stock	53,500	17,759	0
Settlement of receivable from related party	0	-3,979	0
Value of equity interest paid for business acquisition	0	89,406	0
Note issued for business acquisition	15,300	22,867	'
Follow-on Payment for business acquisition (not yet paid)	10,631	0	0
Lucid Markets Trading Limited	'	'	'
Supplemental disclosure of non-cash investing activities	'	'	'
Non-controlling interest	0	160,165	0
Faros Trading LLC	'	'	'
Supplemental disclosure of non-cash investing activities	'	'	'
Non-controlling interest	$15,569	$0	$0

Nature_of_Business_and_Organiz

Nature of Business and Organization	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Nature of Business and Organization	'
	Nature of Business and Organization
	FXCM Inc. (the “Corporation”), a Delaware holding company incorporated on August 10, 2010, is a global online provider of foreign exchange (“FX”) trading and related services to retail and institutional customers worldwide. The Corporation operates through its managing membership interest in FXCM Holding, LLC (“Holdings”), the Corporation’s sole operating asset. Prior to the completion of the reorganization and the Corporation’s initial public offering (“IPO”) described in Note 2, the Corporation was a wholly-owned subsidiary of Holdings. As used in these notes, the term “Company” collectively refers to the Corporation, Holdings and subsidiaries of Holdings.
	As an online provider of FX trading and related services, the Company offers its retail and institutional customers access to global over-the-counter FX markets. In a FX trade, a participant buys one currency and simultaneously sells another, a combination known as a “currency pair.” The Company’s proprietary trading platform presents its FX customers with the price quotations on several currency pairs from a number of global banks, financial institutions and market makers, or FX market makers. The Company’s primary offering to retail customers is what is referred to as agency execution or an agency model. Under the agency model, when a customer executes a trade on the price quotation presented by the FX market maker, the Company acts as a credit intermediary, or a riskless principal, simultaneously entering into a trade with the customer and the FX market maker. The Company earns trading revenue by adding a markup to the price provided by the FX market makers, not trading profit or losses. Additionally, the Company offers its customers the ability to trade contract for differences (“CFDs”), spread betting, equities and equity options through its United Kingdom subsidiaries. CFDs allow for the exchange of the difference in the value of a particular asset such as a stock index or oil or gold contracts, between the time at which a contract is opened and the time at which it is closed. Spread betting allows our customers to bet on the price fluctuations of various financial markets such as FX, indices, oil and metals.
	Institutional trading revenue relates to commission income generated by facilitating spot FX trades on behalf of institutional customers through the services provided by FXCM Pro and Faros Trading LLC ("Faros") (see Note 5). The counterparties to these trades are external financial institutions that also hold customer account balances. The Company receives commission income on these trades without taking any market or credit risk. The Company also offers FX trading services to banks, hedge funds and other institutional customers, on an agency model basis, through its FXCM Pro division and Faros. These services allow customers to obtain optimal prices offered by external banks. The counterparties to these trades are external financial institutions that hold customer account balances and settle the transactions. The Company receives commissions for providing these services. In addition, the Company, through its 50.1% controlling interest in Lucid Markets Trading Limited (“Lucid”) (see Note 5), is an electronic market-maker and trader in the institutional FX market.

Reorganization_and_IPO

Reorganization and IPO	12 Months Ended
	Dec. 31, 2013
Reorganization and IPO Disclosure [Abstract]	'
Reorganization and IPO	'
	Reorganization and IPO
	Reorganization
	Prior to the completion of the Corporation’s IPO, the limited liability company agreement of Holdings (the “LLC Agreement’) was restated among other things, to modify its capital structure by reclassifying the interests held by its existing owners (i.e., the owners of Holdings prior to the IPO) (the “Existing Unit Holders”) into a single new class of units (“Holding Units”). The Existing Unit Holders also entered into an exchange agreement (the “Exchange Agreement”) under which they (or certain permitted transferees thereof) have the right, from and after the first anniversary of the date of the closing of the IPO, subject to the terms of the Exchange Agreement as described therein, to exchange their Holding Units for shares of the Corporation’s Class A common stock on a one-for-one basis, subject to customary conversion rate adjustments for stock splits, stock dividends and reclassifications. Following the IPO, each of the Existing Unit Holders held one share of Class B common stock. The shares of Class B common stock have no economic rights but entitle the holder, without regard to the number of shares of Class B common stock held, to a number of votes on matters presented to stockholders of the Corporation that is equal to the aggregate number of Holding Units held by such holder, subject to customary adjustments for stock splits, stock dividends and reclassifications.
	At the time of the IPO, the Corporation purchased newly-issued Holding Units from Holdings and outstanding Holding Units from the Existing Unit Holders, including members of its senior management, at a purchase price per unit equal to the $14.00 price per share of Class A common stock in the offering net of underwriting discounts. Since the Existing Unit Holders continued to have control of over 50% of the voting shares (through their interests in the Corporation) upon completion of the exchange, the exchange of cash by the Corporation for Holding Units was accounted for as a transaction between entities under common control in accordance with the guidance in Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 805, Business Combinations (“ASC 805”). The date of the exchange was December 7, 2010 (i.e., the effective date of the IPO). As described in more detail in Note 3, subsequent to the IPO and the reorganization described above, the Corporation consolidates the financial results of Holdings and its subsidiaries and reflects the ownership interest of the other members of Holdings as a non-controlling interest in the Corporation’s consolidated financial statements.
	Tax Receivable Agreement
	In connection with the Reorganization, Holdings made an election under Section 754 of the Internal Revenue Code effective for each taxable year in which an exchange of Holding Units shares of Class A common stock as described above occurs, which may result in an adjustment to a portion of the tax basis of the assets of Holdings at the time of an exchange of Holding Units. As a result of both the initial purchase of Holding Units from the Existing Unit Holders in connection with the IPO and these subsequent exchanges, the Corporation is entitled to a proportionate share of the existing tax basis of the assets of Holdings. In addition, the purchase of Holding Units and subsequent exchanges, in conjunction with the election under Section 754 described above, are expected to result in increases in the tax basis of the assets of Holdings that otherwise would not have been available. Both this proportionate share and these increases in tax basis may reduce the amount of tax that the Corporation would otherwise be required to pay in the future. These increases in tax basis may also decrease gains (or increase losses) on future dispositions of certain capital assets to the extent tax basis is allocated to those capital assets.
	The Corporation entered into a tax receivable agreement with Holdings members that will provide for the payment by the Corporation to Holdings members of an amount equal to 85% of the amount of the benefits, if any, that the Corporation is deemed to realize as a result of (i) the existing tax basis in the intangible assets of Holdings on the date of the IPO, (ii) any increases in tax basis resulting from Section 754 election and (iii) certain other tax benefits related to our entering into the tax receivable agreement, including tax benefits attributable to payments under the tax receivable agreement. These payment obligations are obligations of the Corporation and not of Holdings. For purposes of the tax receivable agreement, the benefit deemed realized by the Corporation is computed by comparing the actual income tax liability of the Corporation to the amount of such taxes that the Corporation would have been required to pay had there been no increase to the tax basis of the assets of Holdings as a result of the purchase or exchanges, had there been no tax benefit from the tax basis in the intangible assets of Holdings on the date of the IPO and had the Corporation not entered into the tax receivable agreement. The term of the tax receivable agreement will continue until all such tax benefits have been utilized or expired, unless the Corporation exercises its right to terminate the tax receivable agreement for an amount based on the agreed payments remaining to be made under the agreement or the Corporation breaches any of its material obligations under the tax receivable agreement in which case all obligations will generally be accelerated and due as if the Corporation had exercised its right to terminate the agreement.

Significant_Accounting_Policie

Significant Accounting Policies and Estimates	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Significant Accounting Policies and Estimates	'
	Significant Accounting Policies and Estimates
	Basis of Presentation
	The accompanying consolidated financial statements are presented in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The Company consolidates those entities in which it is the primary beneficiary of a variable-interest entity (VIE) as required by ASC 810, Consolidations (“ASC 810”), or entities where it has a controlling interest. Intercompany accounts and transactions are eliminated in consolidation.
	As indicated above, the Corporation operates and controls all of the businesses and affairs of Holdings and its subsidiaries. As such, the Corporation consolidates the financial results of Holdings and records a non-controlling interest for the economic interest in Holdings not owned by the Corporation. The Corporation’s and the non-controlling unit holders’ economic interest in Holdings was 54.8% and 45.2%, respectively, as of December 31, 2013. The Corporation’s and the non-controlling unit holders’ economic interest in Holdings was 42.5% and 57.5%, respectively, as of December 31, 2012.
	Net income attributable to the non-controlling interest in Holdings in the consolidated statements of operations represents the portion of earnings or loss attributable to the economic interest in Holdings held by the non-controlling unit holders. Net income attributable to other non-controlling interests in the consolidated statements of operations represents the portion of net income attributable to the non-controlling interests of Lucid, Faros and other consolidated subsidiaries or VIE's. Net income attributable to the non-controlling interest in Lucid represents the portion of earnings or loss attributable to the 49.9% economic interest held by Lucid non-controlling members whose allocation among the non-controlling members is not contingent upon services being provided. The portion of the 49.9% of Lucid earnings allocated among the non-controlling members of Lucid contingent on services provided is reported as a component of compensation expense under “Allocation of net income to Lucid members for services provided” in the consolidated statements of operations. Net income or loss attributable to the non-controlling interest in Faros (see Note 5) represents the portion of earnings or loss attributable to the 49.9% economic interest held by Faros non-controlling members. Net income or loss attributable to the non-controlling interests in other consolidated subsidiaries or VIE's represents the portion of earnings or loss attributable to the economic interests held by the non-controlling members.
	Non-controlling interests in the consolidated statements of financial condition represents the portion of equity attributable to the non-controlling interests of Holdings, Lucid, Faros and other consolidated subsidiaries or VIE's. The allocation of equity to the non-controlling interests is based on the percentage owned by the non-controlling interest in the respective entity.
	The Company's consolidated financial statements include the following significant subsidiaries of Holdings:
	Forex Capital Markets LLC	(“US”)
	FXCM Asia Limited	(“HK”)
	Forex Capital Markets Limited	(“UK”)
	FXCM Australia Limited	(“Australia”)
	ODL Group Limited	(“ODL”)
	FXCM Securities Limited	(“FSL”)
	FXCM Japan Securities Co., Ltd.	(“FXCMJ”)
	FXCM UK Merger Limited	(“Merger”)
	Lucid Markets Trading Limited	(“Lucid”)
	Lucid Markets LLP	("Lucid LLP")
	Faros Trading LLC	("Faros")
	Investments where the Company is deemed to exercise significant influence (generally defined as owning a voting interest of 20% to 50% ), but no control, are accounted for using the equity method of accounting. The Company records its pro-rata share of earnings or losses each period and records any dividends as a reduction in the investment balance. The carrying value of these investments are included in Other assets in the consolidated statements of financial condition and earnings or losses are included in Loss on equity method investments, net in the consolidated statements of operations.
	FXCMJ, a wholly owned subsidiary of Holdings, has a fiscal year end of March 31 while the Company has a fiscal year end of December 31. FXCMJ is a Japanese based foreign exchange provider and is required under Japanese law to have a fiscal year end of March 31. The difference between the Company's reporting year end and FXCMJ does not result in a material impact on the Company's financial position or results of operations.
	Certain reclassifications have been made to previously reported amounts to conform to the current presentation.
	Use of Estimates
	The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements as well as the reported amount of revenue and expenses during the year. Actual results could differ from those estimates and could have a material impact on the consolidated financial statements.
	Cash and Cash Equivalents
	Cash and cash equivalents include cash at banks and highly liquid instruments with original maturities of less than 90 days at the time of purchase and cash collateral held by FX and CFD market makers related to hedging activities. At times, balances held in U.S. bank accounts may exceed federally insured limits. This potentially subjects the Company to concentration risk. The Company has not experienced losses in such accounts.
	Cash and Cash Equivalents, held for customers
	Cash and cash equivalents, held for customers represents cash held to fund customer liabilities. At times, balances held in U.S. bank accounts may exceed federally insured limits. This potentially subjects the Company to concentration risk. The Company has not experienced losses in such accounts.
	The balance arises primarily from cash deposited by customers and net realized gains from customer trading activity. The Company records a corresponding liability in connection with this amount that is included in customer account liabilities in the consolidated statements of financial condition (see Note 12). A portion of the balance is not available for general use due to regulatory restrictions in certain jurisdictions. These restricted balances were $1.0 billion as of December 31, 2013 and 2012.
	Due from/to Brokers
	Due from/to brokers represents the amount of the unsettled spot currency trades that the Company has open with its financial institutions. Also included in due from/to brokers is the fair value of derivative financial instruments discussed below. The Company has master netting agreements with its respective counterparties under which its due from/to brokers are presented on a net-by-counterparty basis in accordance with ASC 815 Derivatives and Hedging (“ASC 815”) and ASC Topic 210 Balance Sheet (“ASC 210”).
	Derivatives
	Derivative financial instruments are accounted for in accordance with ASC 815 and are included in Due from/to brokers in the consolidated statements of financial condition. The Company recognizes all derivative financial instruments in the consolidated statements of financial condition as either assets or liabilities at fair value. The Company enters into futures contracts to (i) economically hedge the open customer contracts on its CFD business and (ii) hedge trading in its electronic market making and institutional foreign exchange spot and futures markets. Futures contracts are exchanged traded contracts to either purchase or sell a specific asset at a specified future date for a specified price. Gains or losses on futures contracts related to the Company’s CFD business are included in Retail trading revenue and gains or losses on hedge trading in its electronic market making and institutional foreign exchange spot and futures markets are included in Institutional trading revenue in the consolidated statements of operations (see Note 22).
	Fair Value Measurements
	Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value measurement establishes a fair value hierarchy that prioritizes the inputs of valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. These three levels of fair value hierarchy are defined as follows:
	Level I:  Quoted prices in active markets for identical assets or liabilities, accessible by the Company at the measurement date.
	Level II:  Quoted prices for similar assets or liabilities in active markets, or quoted prices for identical or similar assets or liabilities in markets that are not active, or other observable inputs other than quoted prices.
	Level III:  Unobservable inputs for assets or liabilities.
	When Level I inputs are available, those inputs are selected for determination of fair value. To value derivatives that are characterized as Level II and III, the Company uses observable inputs for similar assets and liabilities that are available from pricing services or broker quotes. These observable inputs may be supplemented with other methods, including internal models that result in the most representative prices for assets and liabilities with similar characteristics. Multiple inputs may be used to measure fair value, however, the level of fair value for each derivative and financial asset or liability is based on the highest priority level of input within this fair value hierarchy.
	Office, Communication and Computer Equipment, net
	Office, communication and computer equipment, net, consist of computer equipment, purchased technology hardware and software, internally developed software, leasehold improvements, furniture and fixtures and other equipment, licenses and communication equipment. Office, communication and computer equipment are recorded at historical cost, net of accumulated depreciation. Additions and improvements that extend the lives of assets are capitalized, while expenditures for repairs and maintenance are expensed as incurred. Certain costs of software developed or obtained for internal use are capitalized. Depreciation is computed using the straight-line method. The Company depreciates these assets using the following useful lives:
	Computer equipment	3 to 5 years
	Software	2 to 5 years
	Leasehold improvements	Lesser of the estimated economic useful life or the term of the lease
	Furniture and fixtures and other equipment	3 to 5 years
	Licenses	2 to 3 years
	Communication equipment	3 to 5 years
	Valuation of Other Long-Lived Assets
	The Company also assesses potential impairments of its other long-lived assets, including office, communication and computer equipment, when there is evidence that events or changes in circumstances indicate that the carrying amount of an asset may not be recovered. An impairment loss is recognized when the carrying amount of the long-lived asset exceeds its fair value and is not recoverable. The carrying amount of a long-lived asset is not recoverable if it exceeds the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset. Any required impairment loss is measured as the amount by which the carrying amount of a long-lived asset exceeds its fair value and is recorded as a reduction in the carrying value of the related asset and a charge to operating results.
	Business Combinations
	The Company accounts for business acquisitions in accordance with ASC 805 and records assets acquired and liabilities assumed at their fair values as of the acquisition date. The Company records any excess purchase price over the value assigned to net tangible and identifiable intangible assets of a business acquired as goodwill. Acquisition related costs are expensed as incurred (see Note 5).
	Goodwill
	The Company recorded goodwill from various acquisitions. Goodwill represents the excess purchase price over the value assigned to the net tangible and identifiable intangible assets of a business acquired. Goodwill is allocated to the Company’s reporting units based on the assignment of the fair values of each reporting unit of the acquired company. For purposes of the goodwill impairment test, the Company has identified its Retail and Institutional trading segments as its reporting units. The Company performs a two-step goodwill impairment review at the reporting unit level annually, or in interim periods if certain events occur indicating that the carrying value may be impaired. The Company tests for impairment during the fourth quarter of our fiscal year using October 1 carrying values.
	The first step of the two-step process involves a comparison of the estimated fair value of a reporting unit to its carrying amount, including goodwill. In performing the first step, the Company determines the fair value of a reporting unit using a DCF analysis. Determining fair value requires the exercise of significant judgment, including judgments about appropriate discount rates, perpetual growth rates, the amount and timing of expected future cash flows. The cash flows employed in the DCF analyses are based on the Company’s most recent budgets and business plans and, when applicable, various growth rates are assumed for years beyond the current business plan period. Discount rate assumptions are based on an assessment of the risk inherent in the future cash flows of the respective reporting units. If the estimated fair value of a reporting unit exceeds its carrying amount, the goodwill of the reporting unit is not impaired and the second step of the impairment test is not necessary. If the carrying amount of a reporting unit exceeds its estimated fair value, then the second step of the goodwill impairment test must be performed. The second step of the goodwill impairment test compares the implied fair value of the reporting unit’s goodwill with its carrying amount to measure the amount of impairment loss, if any. The implied fair value of goodwill is determined in the same manner as the amount of goodwill recognized in a business combination (i.e., the estimated fair value of the reporting unit is allocated to all of the assets and liabilities of that reporting unit including any unrecognized intangible assets as if the reporting unit had been acquired in a business combination and the fair value of the reporting unit was the purchase price paid). If the carrying amount of the reporting unit’s goodwill exceeds the implied fair value of the reporting unit’s goodwill, an impairment loss is recognized in an amount equal to that excess.
	There was no impairment of goodwill for the year ended December 31, 2013. Although there is no impairment as of December 31, 2013, events such as economic weakness and unexpected significant declines in operating results of reporting units may result in our having to perform a goodwill impairment test for some or all of our reporting units prior to the required annual assessment. These types of events and the resulting analysis could result in goodwill impairment charges in the future (see Note 8).
	Other Intangible Assets, net
	Other intangible assets, net, primarily include customer relationships, proprietary technology, non-compete agreements and trade names recorded from various acquisitions.
	The customer relationships, non-compete agreements and trade names are finite-lived intangibles and are amortized on a straight-line basis over their estimated average useful life of 4 to 9 years, 3 to 9 years, and 3 years, respectively. Proprietary technology is also finite-lived intangibles and is amortized on a straight-line basis over their estimated average useful life of 4 to 7 years, respectively. The useful life of these intangibles is based on the period they are expected to contribute to future cash flows as determined by the Company's historical experience. For these finite-lived intangible assets subject to amortization, impairment is considered upon certain “triggering events” and is recognized if the carrying amount is not recoverable and the carrying amount exceeds the fair value of the intangible asset. There was no impairment of finite-lived intangible assets for the years ended December 31, 2013, 2012 and 2011.
	The FX trading license is an indefinite-lived asset that is not amortized but tested for impairment. The Company’s policy is to test for impairment at least annually or in interim periods if certain events occur indicating that the fair value of the asset may be less than its carrying amount. An impairment test on this indefinite-lived asset is performed during the fourth quarter of the Company’s fiscal year using the October 1 carrying value. Impairment exists if the carrying value of the indefinite-lived intangible asset exceeds its fair value. There was no impairment of indefinite-lived intangible assets for the years ended December 31, 2013, 2012 and 2011 (see Note 9).
	Equity Method Investments
	Investments where the Company is deemed to exercise significant influence (generally defined as owning a voting interest of 20% to 50%), but no control, are accounted for using the equity method of accounting. The Company records its pro-rata share of earnings or losses each period and records any dividends as a reduction in the investment balance. Additionally, the carrying value of investments accounted for using the equity method of accounting is adjusted downward to reflect any impairment in value. For investments accounted for using the cost or equity method of accounting, the Company evaluates information (e.g., budgets, business plans, financial statements, etc.) in addition to quoted market prices, if any, in determining whether an other-than-temporary decline in value exists. Factors indicative of an impairment in value include recurring operating losses, credit defaults and subsequent rounds of financing at an amount below the cost basis of the Company’s investment.
	All of the Company’s equity method investments are accounted for at cost. These investments are included in Other assets in the consolidated statements of financial condition and earnings or losses are included in Loss on equity method investments, net in the consolidated statements of operations. Equity method investments are included in institutional and corporate for purposes of segment reporting.
	Accounts Receivable, net
	As of December 31, 2013 and 2012, accounts receivable, net, consisted primarily of amounts due from institutional customers relating to the Company's FX business, and fees receivable from the Company's white label service to third parties and payments for order flow, described in “Retail Trading Revenue” below. Receivables are shown net of reserves for uncollectible accounts. The reserve for bad debts is maintained at a level that management believes to be sufficient to absorb estimated losses in the accounts receivable portfolio. The reserve is increased by the provision for bad debts which is charged against operating results and decreased by the amount of charge-offs, net of recoveries. The amount charged against operating results is based on several factors including, but not limited to, a continuous assessment of the collectability of each account, the length of time a receivable is past due and our historical experience with the particular customer. As of December 31, 2013 and 2012, the reserve netted against receivables in the consolidated statements of financial condition was not material.
Notes Receivable
Notes receivable represent receivable for notes acquired for cash plus accrued interest. Notes receivable are initially recorded at the amount of cash exchanged plus accrued interest. Interest income on the notes is recorded on an accrual basis and included in Interest income in the consolidated statements of operations. The Company individually assesses its notes receivables for impairment using internally generated cash flow projections to determine if the notes will be repaid under the expected terms of the note agreements. If the Company concludes that the counterparty will not repay a note in accordance with its terms, the Company considers the note impaired and begins recognizing interest income on a cash basis, if any. To measure impairment, the Company calculates the estimated fair value of the collateral. If the estimated fair value of the collateral is less than the carrying value of the note receivable, the Company establishes an impairment reserve for the difference. If it is likely that a note will not be collected based on financial or other business indicators, the Company’s policy is to charge off the note in the period which it deems it uncollectible (see Note 10).
Other Assets
Other assets include prepaid expenses, equity method investments, deposits for rent security and deferred debt costs (see Note 11).
Accounts Payable and Accrued Expenses
Accounts payable and accrued expenses include operating expenses payable, amounts due to the Lucid non-controlling members in connection with trade settlements, commissions payable which represents balances owed to referring brokers for trades transacted by customers that were introduced to the Company by such brokers, bonuses payable, income taxes payable, a payable for a portion of the cash consideration relating to the business acquisitions (see Notes 5 and 13) and interest due on borrowings.
Convertible Debt Transactions
The Company separately accounts for the liability and equity components of convertible debt instruments that may be settled entirely or partially in cash upon conversion by allocating the proceeds from issuance between the liability component and the embedded conversion option, or equity component, in accordance with ASC 470, Debt. The value of the equity component is calculated by first measuring the fair value of the liability component, using the interest rate of a similar liability that does not have a conversion feature, as of the issuance date. The difference between the proceeds from the convertible debt issuance and the amount measured as the liability component is recorded as the equity component. The Company recognizes the accretion of the resulting discount as part of interest expense in our consolidated statements of operations.
Contingent Consideration
The Company records a liability for contingent consideration resulting from a business combination at its fair value on the acquisition date included in Other liabilities in the consolidated statements of financial condition. Each reporting period thereafter, the Company revalues this liability and records increases or decreases in the fair value as an adjustment to Other income within the consolidated statements of operations. Changes in the fair value of the contingent consideration liability can result from adjustments in the probability targets of achieving profitability and adjustments to the discount rate.
Foreign Currency
Foreign denominated assets and liabilities are re-measured into the functional currency at exchange rates in effect at the statements of financial condition dates through the consolidated statements of operations. Gains or losses resulting from foreign currency transactions are re-measured using the rates on the dates on which those elements are recognized during the period, and are included in Retail and Institutional trading revenue in the consolidated statements of operations. The Company recorded gains of $5.3 million, $0.8 million and $3.1 million for the years ended December 31, 2013, 2012 and 2011, respectively.
Translation gains or losses resulting from translating the Company’s subsidiaries’ financial statements from the functional currency to the reporting currency, net of tax, are included in Foreign currency translation gain (loss) in the consolidated statements of comprehensive income. Assets and liabilities are translated at the statement of financial condition date while revenues and expenses are translated at an applicable average rate.
Revenue Recognition
The Company makes foreign currency markets for customers trading in FX spot markets and through its subsidiary FSL, engages in equity and related brokerage activities. FX transactions are recorded on the trade date and positions are marked to market daily with related gains and losses, including gains and losses on open spot transactions, recognized currently in income. Commissions earned on brokerage activities are recorded on a trade date basis and are recognized currently in income.
Retail Trading Revenue
Under the Company’s retail agency FX offering, trading revenue is earned by adding a markup to the price provided by FX market makers generating trading revenue based on the volume of transactions and is recorded on trade date. Under the agency model, when a customer executes a trade on the best price quotation presented by the FX market maker, the Company acts as a credit intermediary, or a riskless principal, simultaneously entering into a trade with the customer and the FX market maker. This agency model has the effect of automatically hedging the Company's positions and eliminating market risk exposure. Retail trading revenues principally represent the difference of the Company's realized and unrealized foreign currency trading gains or losses on its positions with customers and the systematic hedge gains and losses from the trades entered into with the FX market makers. Retail trading revenue also includes fees earned from arrangements with other financial institutions to provide platform, back office and other trade execution services. This service is generally referred to as a white label arrangement. The Company earns a percentage of the markup charged by the financial institutions to their customers. Fees from this service are recorded when earned on a trade date basis. Additionally, the Company earns income from trading in CFDs, rollovers, payments for order flow, and spread betting. Income or loss on CFDs represents the difference between the Company's realized and unrealized trading gains or losses on its positions and the hedge gains or losses with the other financial institutions. Income or loss on CFDs is recorded on a trade date basis. Income or loss on rollovers is the interest differential customers earn or pay on overnight currency pair positions held and the markup that the Company receives on interest paid or received on currency pair positions held overnight. Income or loss on rollovers is recorded on a trade date basis. Income earned on order flow represents payments received from certain FX market makers in exchange for routing trade orders to these firms for execution. The Company's order routing software ensures that payments for order flow do not affect the routing of orders in a manner that is detrimental to its retail customers. The Company recognizes payments for order flow as earned on a trade date basis. Spread betting is where a customer takes a position against the value of an underlying financial instrument moving either upward or downward in the market. Income on spread betting is recorded as earned on a trade date basis.
Institutional Trading Revenue
Institutional trading revenue relates to commission income generated by facilitating spot FX trades on behalf of institutional customers through the services provided by FXCM Pro and Faros (see Note 5). The counterparties to these trades are external financial institutions that also hold customer account balances. The Company receives commission income on these trades without taking any market or credit risk. Institutional trading revenue is recorded on a trade date basis. The Company also earns income from market making and electronic trading in the institutional foreign exchange spot and futures markets through Lucid. Income on market making and electronic trading in foreign exchange spot and future currencies represents the spread between the bid and ask price for positions purchased and sold and the change in value of positions purchased and sold. Income on market making is recorded as trading gains, net of trading losses, on a trade date basis.
Interest Income
Interest income consists of interest earned on cash and cash equivalents and cash and cash equivalents, held for customers and is recognized in the period earned. Interest income also includes interest on the Notes receivable.
Other Income
Other income primarily includes amounts earned from the sale of market data, equity and equity option brokerage activities, account maintenance fees, ancillary fee income and recovery of accounts receivable previously written off.
For the year ended December 31, 2013, Other income in the consolidated statements of operations includes $7.0 million of revenue related to the re-measurement of the contingent consideration recorded for the acquisition of Faros (see Note 5), partly offset by a charge of $1.2 million attributable to the re-measurement of the Due to related parties pursuant to tax receivable agreement to reflect a revised U.S. federal tax rate. For the year ended December 31, 2012, Other income in the consolidated statements of operations includes a $1.4 million gain related to a settlement with the former owners of ODL.
For the year ended December 31, 2011, Other income in the consolidated statements of operations includes $4.5 million of revenue related to the termination of a trade execution services contract that resulted in the recognition of previously deferred income and $3.3 million attributable to the re-measurement of the Due to related parties pursuant to tax receivable agreement to reflect the Company’s revised U.S. Federal income tax rate.
Communications and Technology
Communications and technology expense consists primarily of costs for network connections to our electronic trading platforms, telecommunications costs, and fees paid for access to external market data. This expense is affected primarily by the growth of electronic trading, our network/ platform capacity requirements and by changes in the number of telecommunication hubs and connections which provide our customers with direct access to our electronic trading platforms.
Trading Costs, Prime Brokerage and Clearing Fees
Trading costs, prime brokerage and clearing fees primarily represent fees paid to third party clearing banks and prime brokers for clearing foreign exchange spot futures currency and contract transactions, transaction fees paid to exchanges, equity options brokerage activity fees, and fees paid to third party providers for use of their platform for the Company’s market making trading business. Clearing fees primarily fluctuate based on changes in volume, rate of clearing fees charged by clearing banks and rate of fees paid to exchanges.
Referring Broker Fees
Referring broker fees represent commissions paid to brokers for introducing trading customers to the Company. Commissions are determined based on the number and size of transactions executed by the customers and are recorded on a trade date basis.
Compensation and Benefits
Compensation and benefits expense represents employee and member salaries and benefit expense, including stock based compensation expense.
The Company accounts for stock-based compensation in accordance with ASC 718, Compensation-Stock Compensation (“ASC 718”). The fair value of the Company’s stock-based compensation is estimated using the Black-Scholes option pricing model or the fair value of the Corporation’s Class A common stock. The Company recognizes compensation expense for equity awards on a straight-line basis over the requisite service period of the award. Compensation expense is adjusted for an estimate of equity awards that do not vest in the future because service or performance conditions are not satisfied (forfeitures) and have been included in Compensation and benefits in the consolidated statements of operations (see Note 16.)
Compensation and benefits also includes the Allocation of net income to Lucid members for services provided. This expense represents the 49.9% of Lucid's earnings allocated among the non-controlling members of Lucid based on services provided to Lucid.
Advertising and Marketing
Advertising and marketing costs are charged to operations when incurred.
General and Administrative Expenses
General and administrative expenses include bank processing and regulatory fees, professional and consulting fees, occupancy and equipment expense and other administrative costs. Bank processing fees are costs associated with the processing of credit card transactions. Regulatory fees are volume-based costs and annual fees charged by certain regulatory authorities. General and administrative expense for the year ended December 31, 2013 includes a charge of $16.6 million related to a liability established pertaining to a settlement with the FCA regarding our pre August 2010 trade execution practices (see Note 27).
Income Taxes
Holdings operates in the United States (“U.S.”) as a limited liability company that is treated as a partnership for U.S. Federal, state and local income tax purposes. As a result, Holdings' income from its U.S. operations is not subject to U.S. federal income tax because the income is attributable to its members. Accordingly, the Company’s U.S. tax provision is solely based on the portion of Holdings’ income attributable to the Corporation and excludes the income attributable to other members of Holdings whose income is included in Net Income attributable to non-controlling interest in FXCM Holdings, LLC in the consolidated statements of operations.
Income taxes are accounted for in accordance with ASC 740, Income Taxes ("ASC 740"), which requires that deferred tax assets and liabilities are recognized, using enacted tax rates, for the effect of temporary differences between the book and tax basis of recorded assets and liabilities. Deferred tax assets, including net operating losses and income tax credits, are reduced by a valuation allowance if it is "more likely than not" that some portion or all of the deferred tax assets will not be realized (see Note 24).
In addition to U.S. federal and state income taxes, Holdings is subject to Unincorporated Business Tax which is attributable to Holdings' operations apportioned to New York City. The Company’s foreign subsidiaries are also subject to local taxes.
In accordance with ASC 740, we evaluate a tax position to determine whether it is more likely than not that the tax position will be sustained upon examination, based on the technical merits of the position. If the position does not meet a more likely than not threshold, a tax reserve is established and no income tax benefit is recognized. We are audited by U.S. federal and state, as well as foreign, tax authorities. In some cases, many years may elapse before a tax return containing tax positions for which an ASC 740 reserve has been established is examined and an audit is completed. As audit settlements are reached, we adjust the corresponding reserves, if required, in the period in which the final determination is made. While it is difficult to predict the final outcome or timing of a particular tax matter, we believe that our reserves for uncertain tax positions are recorded pursuant to the provisions of ASC 740.
Accounting Pronouncements Adopted in 2012
Fair Value Measurements and Related Disclosures
In May 2011, the FASB issued authoritative guidance that provides a uniform framework for fair value measurements and related disclosures between U.S GAAP and International Financial Reporting Standards. Additional disclosure requirements under this guidance include: (1) for Level III fair value measurements, quantitative information about unobservable inputs used, a description of the valuation processes used by the entity, and a qualitative discussion about the sensitivity of the measurements to changes in the unobservable inputs; (2) for an entity's use of nonfinancial asset that is different from the asset's highest and best use, the reason for the difference; (3) for financial instruments not measured at fair value but for which disclosure of fair value is required, the fair value hierarchy level in which the fair value measurements were determined; and (4)the disclosure of all transfers between Level I and Level II of the fair value hierarchy. This guidance became effective for the Company on January 1, 2012 and did not have a material impact on its consolidated financial statements.
Presentation of Comprehensive Income
In June 2011, the FASB issued authoritative guidance that eliminates the option to present components of other comprehensive income as part of the statement of changes in stockholders' equity, among other updates to the presentation of comprehensive income. Under this guidance, an entity has the option to present the total of comprehensive income, the components of net income and the components of other comprehensive income either in a single continuous statement of comprehensive income or in two separate but consecutive statements. In addition, an entity is required to present on the face of the financial statements reclassification adjustments for items that are reclassified from other comprehensive income to net income in the statement(s) where the components of net income and the components of other comprehensive income are presented. This guidance became effective for the Company on January 1, 2012 and did not have a material impact on its consolidated financial statements.
Accounting Pronouncements Adopted in 2013
Balance Sheet Offsetting
In December 2011, the FASB issued Accounting Standards Update (“ASU”) No. 2011-11 which requires disclosures of both gross and net information about instrument and transactions eligible for offset as well as transactions subject to an agreement similar to a master netting agreement. In February 2013, the FASB issued ASU No. 2013-01 which limited the scope of the offsetting disclosures to recognized derivative instruments accounted for in accordance with ASC 815. ASU No. 2013-01 is effective for annual periods beginning on or after January 1, 2013 and interim periods within those annual periods and must be applied retrospectively. This guidance became effective for the Company on January 1, 2013 and did not have a material impact the presentation of the Company’s unaudited condensed consolidated financial statements.
Testing Goodwill for Impairment
In July 2012, the FASB issued amended guidance relating to FASB ASC Topic 350, Intangibles —  Goodwill and Other, which permits an entity to first assess qualitative factors to determine whether it is more likely than not that an indefinite-lived intangible asset is impaired as a basis for determining whether it is necessary to perform the quantitative impairment test in accordance with ASC Topic 350. The more-likely-than-not threshold is defined as having a likelihood of more than 50 percent. If, after assessing the totality of events and circumstances, an entity concludes that it is not more likely than not that the indefinite-lived intangible asset is impaired, then no further action is required. This guidance became effective for the Company on January 1, 2013. Since this guidance only changes the manner in which the Company assesses indefinite-lived intangible assets for impairment, adoption of this guidance did not have a material effect on the Company’s financial position or results of operations.
Reclassification Out of Accumulated Other Comprehensive Income
In February 2013, the FASB issued ASU No. 2013-02, Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income. This guidance requires an entity to present information about significant items reclassified out of Accumulated Other Comprehensive Income (AOCI) by component and for items reclassified out of AOCI and into net income, an entity must disclose the effect of such items on the affected net income line item. ASU No. 2013-02 is effective for annual periods beginning on or after January 1, 2013 and interim periods within those annual periods and must be applied retrospectively. This guidance became effective for the Company on January 1, 2013 and did not have a material impact the presentation of the Company’s unaudited condensed consolidated financial statements.
Recently Issued Accounting Pronouncement
Certain Obligations Resulting from Joint and Several Liability Arrangements
In February 2013, the FASB issued ASU No. 2013-20, Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation is Fixed at the Reporting Date. This standard requires an entity to measure obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date as the sum of (i) the amount the entity agreed to pay on the basis of its arrangement among its co-obligors and (ii) any additional amount it expect to pay on behalf of its co-obligors.
ASU No. 2013-20 is effective for fiscal years and interim periods beginning after December 15, 2013, but earlier adoption is permitted. Upon adoption, the standard should be applied retrospectively to all prior periods presented. The Company plans to adopt the standard on its required effective date of January 1, 2014 and does not expect the adoption of this standard to have a material effect on our consolidated financial condition, results of operations or cash flows.
Parent's Accounting for the Cumulative Translation Adjustment upon Derecognition of an Investment within a Foreign Entity or of an Investment in a Foreign Entity
In March 2013, the FASB issued ASU No. 2013-05, Parent's Accounting for the Cumulative Translation Adjustment upon Derecognition of Certain Subsidiaries or Groups of Assets within a Foreign Entity or of an Investment in Foreign Entity. This standard addresses whether consolidation guidance or foreign currency guidance applies to the release of the cumulative translation adjustment into net income when a parent sells all or a part of its investment in a foreign entity or no longer holds a controlling financial interest in a subsidiary or net assets that are a business (other than a sale of in-substance real estate) within a foreign entity. The standard also resolves the diversity in practice for the cumulative translation adjustment treatment in business combinations achieved in stages involving foreign entities.
Under this standard, the entire amount of the cumulative translation adjustment associated with the foreign entity should be released into earnings when there has been: (i) a sale of a subsidiary or group of net assets within a foreign entity and the sale represents a complete or substantially complete liquidation of the foreign entity in which the subsidiary or the net assets had resided; (ii) a loss of a controlling financial interest in an investment in a foreign entity; or (iii) a change in accounting method from applying the equity method to an investment in a foreign entity to consolidating the foreign entity.
ASU No. 2013-05 is effective for fiscal years and interim periods beginning after December 15, 2013, and will be applied prospectively. The Company plans to adopt the standard on its required effective date of January 1, 2014 and does not expect the adoption of the standard to have a material effect on our consolidated financial condition, results of operations or cash flows.
Presentation of Unrecognized Tax Benefits
In July 2013, the FASB issued ASU No. 2013-11, Presentation of Unrecognized Tax Benefits When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. This standard requires a liability related to unrecognized tax benefits to be presented as a reduction to the related deferred tax asset for a net operating loss carryforward or a tax credit carryforward. When the carryforwards are not available at the reporting date under the tax law of the applicable jurisdiction or the tax law of the applicable jurisdiction does not require, and the entity does not intend to use, the deferred tax asset for such purpose, the unrecognized tax benefit will be presented in the financial statements as a liability and will not be combined with the related deferred tax asset.
ASU No. 2013-11 is effective for fiscal years and interim periods beginning after December 15, 2013, but earlier adoption is permitted. Upon adoption, the standard should be applied prospectively to unrecognized tax benefits that existed at the effective date. Retrospective application is permitted. The Company plans to adopt the standard prospectively on its required effective date of January 1, 2014 and does not expect the adoption of the standard to have a material effect on its consolidated financial condition, results of operations or cash flows.

NonControlling_Interest

Non-Controlling Interest	12 Months Ended
	Dec. 31, 2013
Noncontrolling Interest [Abstract]	'
Non-Controlling Interest	'
	Non-Controlling Interests
	Holdings
	The Corporation consolidates the financial results of Holdings whereby it records a non-controlling interest for the economic interest in Holdings not owned by the Corporation. Pursuant to an agreement between the Corporation and Holdings, anytime the Corporation cancels, issues or repurchases shares of its Class A common stock, Holdings enters into an equivalent Holding Unit transaction with the Corporation. In addition, anytime Existing Unit Holders exchange their Holding Units for shares of the Corporation’s Class A common stock, Holdings is required to transfer an equal amount of Holding Units to the Corporation.
	Changes in the non-controlling and the Corporation’s interests in Holdings for the year ended December 31, 2013 are presented in the following table:
		Controlling Units		Non-		Total Units		FXCM		Non-		Total
				Controlling Units				Inc.		Controlling
	Balance as of January 1, 2013	34,683,599		46,930,192		81,613,791		42.5	%	57.5	%	100	%
	Holding Units repurchased related to Class A common stock repurchased	(1,815,800	)	—		(1,815,800	)	(0.8	)%	0.8	%	—	%
	Holding Units acquired by FXCM Inc. related to exchanges of Holding Units for shares of Class A common stock	10,094,371		(10,094,371	)	—		12.3	%	(12.3	)%	—	%
	Exercise of stock options	1,702,714		—		1,702,714		0.8	%	(0.8	)%	—	%
	Balance as of December 31, 2013	44,664,884		36,835,821		81,500,705		54.8	%	45.2	%	100	%
	Lucid, Faros and Other Non-Controlling Interests
	The Company owns a controlling interest in Lucid, Faros and other entities and consolidates the financial results of these entities whereby it records a non-controlling interest for the economic interests not owned by the Company.

Business_Acquisition

Business Acquisition	12 Months Ended
	Dec. 31, 2013
Business Combinations [Abstract]	'
Business Acquisition	'
	Business Acquisition
	Faros
	On September 20, 2013 (the “Faros Acquisition Date”), the Company acquired a 50.1% controlling interest in Faros. Faros provides foreign exchange intelligence, market coverage, and execution services to the institutional foreign exchange market. The acquisition further expands the Company's presence and capabilities in the institutional marketplace. As consideration, the Company provided an initial cash payment of $5.0 million (the “Initial Payment”) and a follow-on payment (the “ Follow-on Payment”) to be made in 2015 in an amount to be determined, based on the purchase agreement (the “Faros Purchase Agreement”) estimated at $10.6 million on the Faros Acquisition Date for a total estimated purchase price of $15.6 million. Pursuant to the terms of the Faros Purchase Agreement, the Follow-on Payment is a multiple of Faros' 2014 EBITDA and is payable partly in shares of the Corporation’s Class A common stock to one of the Faros sellers if certain criteria are met. Under the terms of the Faros Purchase Agreement, any of the Corporation’s Class A common stock issued to the Faros seller will be restricted for sale until September 2021 if the Faros seller ceases to be employed by Faros as of either December 31, 2015 or December 31, 2016 for reasons other than death, disability or the sale of the majority of the Corporation’s combined voting power. This restriction ("the Faros Liquidity Restriction") has an estimated fair value of $0.4 million at the Faros Acquisition Date and is accounted for as deferred compensation and recognized over the term of the restriction.
	The Company has the option to buy out the remaining interest of the Faros sellers subject to the terms of the Faros Purchase Agreement. In the event the buyout is not exercised by the Company by December 31, 2017, the sellers have the right, subject to the terms of the Faros Purchase Agreement, to market Faros for sale of all the membership interests of Faros.
	The fair value of the Follow-on Payment is included in Other liabilities in the consolidated statements of financial condition. Changes in the fair value of the Follow-on Payment subsequent to the Faros Acquisition Date are recognized in earnings in the period in which the change is recorded. The Company estimated the fair value of the Follow-on Payment using both a discounted cash flow model and guideline public company model. The discount rate considered in the assessment of the $10.6 million Follow-on Payment at the Faros Acquisition Date was 25.0%. As of December 31, 2013, the fair value of the Follow-on Payment was estimated at $3.7 million. The $7.0 million decrease in the estimated fair value was recorded in Other income in the consolidated statement of operations (see Note 23). The decline in the estimated fair value of the Follow-on Payment is due to lowering our Faros EBITDA estimate.
	The acquisition was accounted for in accordance with ASC 805. The assets acquired, liabilities assumed and non-controlling interest were recorded at their estimated fair values in accordance with ASC 820 at the Faros Acquisition Date as summarized in the table below. Full goodwill of $23.0 million was calculated as the fair value of estimated consideration over the estimated fair value of the net assets acquired. The estimated fair value of the non-controlling interest was $15.6 million, and was determined by valuing Faros using a discounted cash flow model and guideline public company model, less the Initial Payment and the Follow-on Payment. The estimate of the fair value of the non-controlling interest is based on an assumed discount rate of 25.0%, long term annual earnings growth rate of 3.0% and assumed adjustments due to the lack of control that market participants would consider when estimating the fair value of the non-controlling interest in Faros. Goodwill was allocated at the reporting unit level in the Institutional segment based on an analysis of the fair value of assets acquired and expected future benefits of synergies created from combining the Faros business with the Company's foreign exchange trading expertise. Faros is included in the Institutional segment for purposes of segment reporting (see Note 26).
	Faros Purchase Price Allocation
	(Amounts in thousands)
	Purchase price				$	15,631
	Non-controlling interest				15,569
	Total fair value at Acquisition Date				31,200
	Net assets acquired	$	137
	Adjustments to reflect acquired assets and liabilities at fair value
	Customer relationships (1)	6,000
	Non-compete agreement (2)	1,900
	Trade name (3)	130
	Fair value of net assets acquired				8,167
	Goodwill resulting from the Faros acquisition				$	23,033
	(1)	Consists of institutional and bank customers, with an amortization life of 4 years.
	(2)	Amortization life is 9 years.
	(3)	Amortization life is 3 years.
	The amounts included in the Faros Purchase Price Allocation table represent the preliminary allocation of the purchase price and are subject to revision during the remainder of the measurement period, a period not to exceed 12 months from the Faros Acquisition Date. Adjustments, if any, to the provisional values during the measurement period will be pushed back to the date of acquisition. Comparative information for periods after acquisition but before the period in which the adjustments are identified will be adjusted to reflect the effects of the adjustments as if they were taken into account as of the acquisition date. Changes to the amounts recorded as assets and liabilities may result in a corresponding adjustment to goodwill. As a result of changes identified to the net assets acquired, the initial goodwill was increased by $0.8 million to $23.0 million at December 31, 2013.
	The following condensed statement of net assets acquired reflects the amounts of Faros net assets recognized as of the Faros Acquisition Date, with amounts in thousands:
	Condensed Statement of Net Assets Acquired
		As of September 20, 2013
	Assets
	Cash and cash equivalents	$	1,055
	Accounts receivable, net	40
	Office, communication and computer equipment, net	31
	Intangible assets	8,030
	Other assets	76
	Total assets	$	9,232
	Liabilities
	Accounts payable and accrued expenses	1,065
	Total liabilities	1,065
	Fair value of net assets acquired	$	8,167
	Contingencies and Accounts Receivable
	There were no contingent liabilities recorded in the fair value of net assets acquired as of the Faros Acquisition Date and the fair value of net assets acquired includes accounts receivables with book value that approximates fair value. There was no reserve netted against receivables as of the Faros Acquisition Date since based on current information and events, it is probable that the Company will collect all amounts due according to the contractual terms of the receivable.
	Condensed Combined Financial Information:
	The following condensed financial information presents the resulting operations of Faros from the Faros Acquisition Date to December 31, 2013, with amounts in thousands:
		For the period September 20, 2013 to December 31, 2013
	Total revenue	$	526
	Net loss	$	(301	)
	Lucid
	On June 18, 2012 (the “Acquisition Date”), the Company acquired a 50.1% controlling interest in Lucid, an electronic market maker and trader in the institutional foreign exchange spot and futures markets headquartered in the U.K., to expand the Company's presence and capabilities in the institutional marketplace. Lucid's sole material asset is a controlling membership interest in Lucid LLP, an electronic market maker and trader in the institutional foreign exchange spot and futures markets headquartered in the U.K. As consideration, the Company issued $71.4 million, 3.5% unsecured promissory notes, and 9.0 million unregistered shares of the Corporation's Class A common stock to Lucid sellers as well as a $15.8 million, 3.5% unsecured promissory note for all liquid assets for a total estimated purchase price of $177.5 million. The Lucid sellers were entitled to 1.8 million shares of the 9.0 million shares at closing, with the remaining 7.2 million shares held in escrow (the “Remaining Shares”), subject to the achievement of certain fixed profit-based targets (the “Profit Targets”). If the Profit Targets are achieved, the Lucid sellers are entitled to receive the Remaining Shares on the first, second and third anniversary following the Acquisition Date or over a three year term (the “Term”) pursuant to the sale purchase agreement (the “Purchase Agreement”) (see Note 14). Pursuant to the terms of the Acquisition, any of the Corporation’s common shares issuable to a Lucid seller on an anniversary from closing will be restricted (the “Lucid Liquidity Restriction”) for sale until the eighth anniversary of the closing of the Acquisition if the recipient ceases to be employed by Lucid or any entity controlled by the Corporation for reasons other than death or incapacity on such anniversary. The Purchase Agreement includes a contingent arrangement which provides for a claw back of the Remaining Shares in the event that the Profit Targets are not achieved. Additionally, the Company has the option to buy-out the remaining interest of the Lucid sellers subject to terms of the Purchase Agreement. In the event the buy-out is not exercised by the Company within four years from the Acquisition Date, the Lucid sellers have the ability to buy-back the Company’s ownership interests within 30 days of the fourth anniversary date.
	The estimated fair value of the 9.0 million shares was $89.4 million and is accounted for as equity. This fair value consisted of 1.8 million shares with a fair value of $21.5 million based on the Corporation’s closing stock price as of the Acquisition Date and the Remaining Shares with an estimated fair value of $67.9 million, adjusted for the Lucid Liquidity Restriction. The estimated fair value of the Lucid Liquidity Restriction was $9.4 million, and is accounted for as deferred compensation and recognized over the Term.
	The Acquisition was accounted for in accordance with ASC 805. The assets acquired, liabilities assumed and non-controlling interest were recorded at their estimated fair values in accordance with ASC 820 at the Acquisition Date as summarized in the table below. Full goodwill of $236.5 million was calculated as the fair value over the estimated fair value of the net assets acquired. The estimated fair value of the non-controlling interest was $160.2 million, and was determined by valuing Lucid using a discounted cash flow method, less the considerations transferred. The estimate of the fair value of the non-controlling interest is based on an assumed discount rate between 10.0% and 11.0%, annual earnings growth rate of 4.0% and assumed adjustments due to the lack of control that market participants would consider when estimating the fair value of the non-controlling interest in Lucid. Goodwill was allocated at the reporting unit level in the Institutional segment based on an analysis of the fair value of assets acquired and expected future benefits of synergies created from combining the Lucid market making business with the Company's foreign exchange trading expertise. The goodwill is deductible for U.K. income tax purposes.
	During the year ended December 31, 2013, the purchase price was increased by $15.3 million due to the final determination of tax balances at the Acquisition Date adjusted during the measurement period. The Company issued six-month 2.25% unsecured promissory notes to the Lucid sellers for the purchase price increase (see Note 21). In connection with this purchase price adjustment, the initial goodwill recorded was reduced by $1.2 million to $235.3 million.
	Lucid Purchase Price Allocation (¹)
	(Amounts in thousands)
	Purchase price				$	192,784
	Non-Controlling interest				160,165
	Total fair value at Acquisition Date				352,949
	Net assets acquired	$	32,732
	Adjustments to reflect acquired assets and liabilities at fair value
	Proprietary technology (2)	83,900
	Non-compete agreements (3)	1,000
	Fair value of net assets acquired				117,632
	Goodwill resulting from the Lucid acquisition				$	235,317
	__________________
	(¹) The amounts included in the Lucid Purchase Price Allocation table represent the allocation of the purchase price and includes revisions made during the 12 months remeasurement period from the Acquisition Date.
	(²) Consists of internally developed software platforms through which the Company: (i) executes its specific trading strategies, with an amortization life of 4 years and (ii) clears and efficiently settle trades, with an amortization life of 7 years.
	(³) Consists of two non-compete agreements with amortization lives of 3 years.
The amounts included in the Lucid Purchase Price Allocation table represent the preliminary allocation of the purchase price and were subject to revision during the measurement period, a period not to exceed 12 months from the acquisition date. Adjustments to the provisional values during the measurement period were pushed back to the date of acquisition. Comparative information for periods after acquisition but before the period in which the adjustments were identified were adjusted to reflect the effects of the adjustments as if they were taken into account as of the acquisition date. Changes to the amounts recorded as assets and liabilities resulted in a corresponding adjustment to goodwill.
Condensed Statement of Net Assets Acquired
The following condensed statement of net assets acquired reflects the amounts of Lucid net assets recognized as of the Acquisition Date, with amounts in thousands:
	As of June 18, 2012
Assets
Cash and cash equivalents	$	28,656
Accounts receivable, net	5,100
Due from brokers	302
Deferred tax asset	11,311
Office, communication and computer equipment, net	499
Intangible assets	84,900
Other assets	226
Total assets	$	130,994
Liabilities
Accounts payable and accrued expenses	13,362
Total liabilities	13,362
Fair value of net assets acquired	$	117,632
Contingencies and Accounts Receivable
There were no contingent liabilities recorded in the fair value of net assets acquired as of the Acquisition Date. The Company has collected all material accounts receivable amounts as of December 31, 2013.
Condensed Combined Financial Information:
The following condensed financial information presents the resulting operations of Lucid from the Acquisition Date to December 31, 2012:
	For the period June 18, 2012 to December 31, 2012
Total revenue	$	42,198
Net income	$	21,446
Foreland
On October 7, 2011, the Company acquired a 100% interest in Foreland (the “Foreland Acquisition”), a Japan based foreign exchange provider. The Foreland Acquisition was designed to increase the Company’s profile in the Japanese market and accelerate its growth in Asia, utilizing Foreland’s relationships and sales force. The Company’s purchase price was $37.7 million provided in cash. The Foreland Acquisition was accounted for in accordance with ASC 805. The assets acquired and the liabilities assumed were recorded at their fair values in accordance with ASC 820.
The $37.7 million purchase price was allocated to Foreland assets acquired and liabilities assumed based on their estimated fair values at the acquisition date as summarized in the following table. Goodwill of $10.0 million was calculated as the purchase premium after adjusting for the fair value of net assets acquired. Goodwill was allocated to the Retail Trading segment based on an analysis of the fair value of assets acquired and expected future benefits of synergies created from combining Foreland’s FX business with the Company’s foreign exchange trading expertise, the economies of scale expected from combining the operations of the two companies and the retail relationships brought by the Foreland’s management. No goodwill is expected to be deductible for federal income tax purposes.
Foreland Purchase Price Allocation
(Amounts in thousands)
Purchase price				$	37,654
Net assets acquired	$	21,460
Adjustments to reflect acquired assets and liabilities at fair value
Customer relationships(1)	9,925
Deferred tax liability	(3,726		)
Fair value of net assets acquired				27,659
Goodwill resulting from the Foreland acquisition				$	9,995
_______________
(1)	Consists of retail customers. The amortization life is 6 years.
Condensed Statement of Net Assets Acquired
The following condensed statement of net assets acquired reflects the amounts of Foreland net assets recognized as of October 7, 2011, with amounts in thousands:
	As of October 7, 2011
Assets
Cash and cash equivalents	$	29,853
Cash and cash equivalents, held for customers	172,826
Accounts receivable, net	501
Office, communication and computer equipment, net	847
Intangible assets	9,934
Other assets	1,199
Total assets	$	215,160
Liabilities
Customer account liabilities	$	172,826
Accounts payable and accrued expenses	6,502
Due to brokers	4,447
Deferred tax liability	3,726
Total liabilities	187,501
Fair value of net assets acquired	$	27,659
Accounts Receivable
The Company has collected all material accounts receivable amounts as of December 31, 2013.
FXCMJ
On March 31, 2011, the Company acquired a 100% interest in FXCMJ (the “FXCMJ Acquisition”), a Japan based foreign exchange provider that had previously contracted to use the FXCM Japan trademark. The FXCMJ Acquisition was designed to increase the Company’s profile in the Japanese market and accelerate its growth in Asia, utilizing FXCMJ’s relationships and sales force. The Company’s purchase price was $15.7 million provided in cash. The FXCMJ Acquisition was accounted for in accordance with ASC 805. The assets acquired and the liabilities assumed were recorded at their fair values in accordance with ASC 820.
The $15.7 million purchase price was allocated to FXCMJ assets acquired and liabilities assumed based on their estimated fair values at the acquisition date as summarized in the following table. Goodwill of $0.8 million was calculated as the purchase premium after adjusting for the fair value of net assets acquired. Goodwill was allocated to the Retail Trading segments based on an analysis of the fair value of assets acquired and expected future benefits of synergies created from combining FXCMJ’s foreign exchange with the Company’s foreign exchange trading expertise, the economies of scale expected from combining the operations of the two companies and the retail relationships brought by the FXCMJ’s management. No goodwill is expected to be deductible for federal income tax purposes.
FXCM Japan Inc. Purchase Price Allocation
(Amounts in thousands)
Purchase price				$	15,725
Net assets acquired	$	14,301
Adjustments to reflect acquired assets and liabilities at fair value
Customer relationships (1)	1,055
Deferred tax liability	(397		)
Fair value of net assets acquired				14,959
Goodwill resulting from the FXCMJ acquisition				$	766
_______________
(1)	Consists of retail customers. The amortization life is 6 years.
Condensed Statement of Net Assets Acquired
The following condensed statement of net assets acquired reflects the amounts of FXCMJ net assets recognized as of March 31, 2011, with amounts in thousands:
	As of March 31, 2011
Assets
Cash and cash equivalents	$	9,827
Cash and cash equivalents, held for customers	114,024
Due from broker	3,885
Accounts receivable, net	194
Tax receivable	478
Office, communication and computer equipment, net	2,279
Intangible assets	1,064
Other assets	1,189
Total assets	$	132,940
Liabilities
Customer account liabilities	$	114,023
Accounts payable and accrued expenses	3,561
Deferred tax liability	397
Total liabilities	117,981
Fair value of net assets acquired	$	14,959
Accounts Receivable
The Company has collected all material accounts receivable amounts as of December 31, 2013.
Pro Forma Condensed Combined Financial Information
Pro forma condensed combined financial information for the acquisitions completed in 2013 (i.e., Faros), 2012 (i.e., Lucid) and 2011 (i.e., Foreland and FXCMJ) are presented as they may have appeared if all acquisitions had been completed on January 1, 2013, 2012 and 2011, with amounts in thousands:
	For the Years Ended
	December 31, 2013			December 31, 2012		December 31, 2011
Total revenues	$	491,217		$	463,767	$	588,028
Net income before non-controlling interest	$	32,463		$	49,224	$	115,884
These pro forma results for the years ended December 31, 2013, 2012 and 2011 primarily include the related tax impact and the elimination of certain revenues and expenses resulting from transactions conducted with Lucid, Foreland, and FXCMJ prior to these acquisitions as well as the adjustments for the intangible assets acquired in the Faros acquisition and the related tax impact.
Acquisition-related Costs
For the year ended December 31, 2013, acquisition-related transaction costs for the Faros acquisition were not significant. For the year ended December 31, 2012, acquisition-related costs for Lucid were $0.9 million. For the year ended December 31, 2011, acquisition-related transaction costs for the acquisitions were $0.2 million for the acquisition of Foreland and $0.3 million for the acquisition of FXCMJ. Acquisition-related transaction costs are included in General and administrative expense in the consolidated statements of operations.

Equity_Method_Investment

Equity Method Investment	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Equity Method Investment	'
	Equity Method Investment
	On December 4, 2012, the Company completed the acquisition of a non-controlling equity interest in an electronic communication network for foreign exchange trading. As the Company holds a 38% equity interest and exerts significant influence, the investment is accounted for using the equity method and is included in institutional for purposes of segment reporting (see Note 26). The Company also has 26.3% equity interest in a developer of FX trading software which is accounted for using the equity method and is included in corporate for purposes of segment reporting.
	As of December 31, 2013 and 2012, the Company’s carrying values of equity method investments were $9.8 million and $12.0 million, respectively, and are included as a component of Other assets in the consolidated statements of financial condition.
	Loss on equity method investments was $0.8 million for the year ended December 31, 2013 and is included in Loss on equity method investments, net in the consolidated statements of operations. Income or loss recognized from equity method investments was not material for the years ended December 31, 2012 and 2011.
	Dividend distributions received from the Company's equity method investments during the year ended December 31, 2013 were not significant. There were no dividend distributions received from the Company’s equity method investments during the years ended December 31, 2012 and 2011.

Office_Communication_and_Compu

Office, Communication and Computer Equipment, net	12 Months Ended
	Dec. 31, 2013
Property, Plant and Equipment [Abstract]	'
Office, Communication and Computer Equipment, net	'
	Office, Communication and Computer Equipment, net
	Office, communication and computer equipment, net, including capitalized software development costs, leasehold improvements, capital leases, furniture and fixtures and other equipment, licenses and communication equipment, consisted of the following as of December 31, 2013 and 2012, with amounts in thousands:
		December 31, 2013			December 31, 2012
	Computer equipment	$	28,047		$	34,541
	Software	47,138			31,476
	Leasehold improvements	9,687			9,478
	Furniture and fixtures and other equipment	3,427			3,185
	Licenses	10,101			20,222
	Communication equipment	1,664			1,522
		100,064			100,424
	Less: Accumulated depreciation	(50,899		)	(50,108		)
	Office, communication and computer equipment, net	$	49,165		$	50,316
	Depreciation is computed on a straight-line basis (see Note 3). Depreciation expense, including impairments, included in the consolidated statements of operations was $25.8 million, $17.7 million, and $13.1 million for the years ended December 31, 2013, 2012 and 2011, respectively. Also included in depreciation expense was amortization expense of capitalized software development cost in the amount of $10.6 million, $6.5 million, and $3.0 million for the years ended December 31, 2013, 2012 and 2011, respectively. Unamortized capitalized software development costs were $26.0 million and $20.3 million as of December 31, 2013 and 2012, respectively. Assets disposed of during the year ended December 31, 2013 were $19.2 million. The Company disposed of $2.9 million of fully depreciated assets during the year ended December 31, 2012. For the year ended December 31, 2013, the Company recorded an impairment of $3.5 million to write down the value of an electronic FX option trading platform. The net realizable value of the asset was determined based on DCFs over the remaining useful life. The impairment charge is included in Depreciation and amortization in the consolidated statements of operations. The impairment charge is included in retail trading for purposes of segment reporting.

Goodwill

Goodwill	12 Months Ended
	Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Goodwill	'
	Goodwill
	The following table presents the changes in goodwill by segment during the year ended December 31, 2013, with amounts in thousands:
		Retail Trading			Institutional Trading			Total
	Balance at January 1, 2013	$	37,851		$	247,803		$	285,654
	Goodwill acquired	—			23,033			23,033
	Goodwill adjustment/remeasurement	1,387			(1,196		)	191
	Foreign currency translation adjustment	(1,159		)	217			(942		)
	Balance at December 31, 2013	$	38,079		$	269,857		$	307,936

Other_Intangible_Assets_net

Other Intangible Assets, net	12 Months Ended
	Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Other Intangible Assets, net	'
	Other Intangible Assets, net
	The Company’s acquired intangible assets consisted of the following as of December 31, 2013 and 2012, with amounts in thousands:
		December 31, 2013									December 31, 2012
		Gross Carrying Amount			Accumulated Amortization			Net Carrying Amount			Gross Carrying Amount			Accumulated Amortization			Net Carrying Amount
	Finite-lived intangible assets
	Customer relationships	$	37,746		$	(14,529	)	$	23,217		$	32,269		$	(9,815	)	$	22,454
	Non-compete agreements	10,507			(8,177		)	2,330			8,214			(5,841		)	2,373
	Proprietary technology	83,900			(31,849		)	52,051			83,900			(11,081		)	72,819
	Trade name	177			(13		)	164			—			—			—
	Foreign currency translation adjustment	(1,831		)	172			(1,659		)	(220		)	(244		)	(464		)
	Total finite-lived intangible assets	$	130,499		$	(54,396	)	$	76,103		$	124,163		$	(26,981	)	$	97,182
	Indefinite-lived intangible assets
	License	610			—			610			610			—			610
	Total indefinite-lived intangible assets	$	610		$	—		$	610		$	610		$	—		$	610
	Customer relationships, non-compete agreements, proprietary technology and trade name are amortized on a straight-line basis over 4 to 9 years, 3 to 9 years, 4 years and 7 years, and 3 years, respectively, which approximates the weighted average useful lives. Indefinite-lived assets are not amortized (see Note 3). Amortization expense included in the consolidated statements of operations was $27.9 million, $19.0 million and $6.9 million for the years ended December 31, 2013, 2012 and 2011 respectively. Estimated future amortization expense for acquired intangible assets outstanding as of December 31, 2013 is as follows, with amounts in thousands:
	Year Ending December 31,	Estimated Amortization Expense
	2014	$	27,655
	2015	27,431
	2016	15,562
	2017	3,068
	2018	1,022
	Thereafter	1,365
		$	76,103

Notes_Receivable

Notes Receivable	12 Months Ended
	Dec. 31, 2013
Receivables [Abstract]	'
Notes Receivable	'
	Notes Receivable
	On October 2, 2013, the Company acquired 4.0% notes receivable aggregating $11.9 million (the “Notes”) from Infinium Capital Holdings (“Infinium Capital”). The principal of the Notes is payable in two lump sums with 50% due on August 1, 2014 and the remaining 50% due on August 1, 2015. The Notes are secured by liens on capital stock, equity interest held and certain other subsidiaries and other assets of Infinium Capital. As of December 31, 2013 there was no reserve against the Notes receivable.

Other_Assets

Other Assets	12 Months Ended
	Dec. 31, 2013
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]	'
Other Assets	'
	Other Assets
	Other assets were comprised of the following as of December 31, 2013 and 2012, with amounts in thousands:
		31-Dec-13		31-Dec-12
	Prepaid expenses	$	5,738	$	5,439
	Equity method investments	9,793		12,000
	Deferred debt issuance costs	7,131		1,109
	Deposits	1,492		1,555
	Other	162		13
		$	24,316	$	20,116

Customer_Account_Liabilities

Customer Account Liabilities	12 Months Ended
	Dec. 31, 2013
Other Liabilities Disclosure [Abstract]	'
Customer Account Liabilities	'
	Customer Account Liabilities
	Customer account liabilities represent amounts due to customers related to cash and margin transactions. This includes cash deposits and gains and losses on settled FX, CFDs and spread betting trades as well as unrealized gains and losses on open FX commitments, CFDs and spread betting. Customer account liabilities were $1.2 billion as of December 31, 2013 and 2012.

Accounts_Payable_and_Accrued_E

Accounts Payable and Accrued Expenses	12 Months Ended
	Dec. 31, 2013
Payables and Accruals [Abstract]	'
Accounts Payable and Accrued Expenses	'
	Accounts Payable and Accrued Expenses
	Accounts payable and accrued expenses were comprised of the following as of December 31, 2013 and 2012, with amounts in thousands:
		December 31, 2013		December 31, 2012
	Operating expenses payable	$	41,528	$	28,793
	Due to Lucid non-controlling members	9,995		9,611
	Commissions payable	9,485		8,126
	Bonus payable	7,455		3,945
	Income tax payable	1,046		1,231
	Acquisition cash consideration payable	—		808
	Interest due on borrowings	177		121
	Other	11		—
		$	69,697	$	52,635

Earnings_per_Share

Earnings per Share	12 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Earnings per Share	'
	Earnings per Share
	Basic earnings per share (“EPS”) measures the performance of an entity over the reporting period. Diluted EPS measures the performance of an entity over the reporting period while giving effect to all potentially dilutive common shares that were outstanding during the period. The Company uses the treasury stock method in accordance with ASC Topic 260 — Earnings per Share (“ASC 260”), to determine the diluted EPS.
	In accordance with ASC 260, all outstanding unvested share-based payments that contain rights to non-forfeitable dividends participate in the undistributed earnings with the common stockholders and are therefore participating securities. The shares of Class B common stock do not share in the earnings of the Company and are therefore not participating securities. Accordingly, basic and diluted net earnings per share of Class B common stock have not been presented.
	During the year ended December 31, 2013, the Company granted 105,636 and 426,000 stock options to purchase shares of the Corporation’s Class A common stock to its independent directors and employees, respectively. For the year ended December 31, 2012, the Company granted 109,488 and 725,000 stock options to purchase shares of the Corporation’s Class A common stock to its independent directors and employees, respectively. For the years ended December 31, 2013 and 2012, stock options granted to certain employees, non-employees and independent directors in the aggregate of 426,000 and 9,178,128, respectively, were not included in the computation of earnings per common share because they were antidilutive under the treasury method.
	As discussed in Note 5, the Company issued 7.2 million shares of the Corporation’s Class A common stock in connection with the Lucid acquisition subject to the achievement of certain Profit Targets. If the Profit Targets are achieved, the Lucid sellers are entitled to receive 1.2 million shares on the first anniversary, 3.0 million shares on the second anniversary and 3.0 million shares on the third anniversary of the Acquisition Date. In accordance with ASC 260, the anniversary shares are considered contingently issuable shares. Accordingly, they are considered outstanding common shares and included in basic EPS as of the date that all necessary conditions have been satisfied (that is, when issuance of the shares is no longer contingent) and there is no circumstance under which those shares would not be issued. In accordance with ASC 260, shares whose issuance is contingent upon the satisfaction of certain conditions shall be considered outstanding and included in the computation of diluted EPS if all necessary conditions have been satisfied by the end of the period. During the year ended December 31, 2013, the Profit Targets for the 1.2 million first anniversary shares were achieved and these shares are included in the computation of basic and diluted EPS for the year ended December 31, 2013. In accordance with ASC 260, the first anniversary shares were not included in the computation of basic or diluted EPS for the year ended December 31, 2012 and the second and third anniversary shares were not included in the computation of basic or diluted EPS for the year ended December 31, 2013 and 2012.
	As described in Note 21, in June 2013 FXCM Inc. issued $172.5 million principal amount of 2.25% Senior Convertible Notes maturing on June 15, 2018 (the “Convertible Notes”). The Convertible Notes will be convertible at an initial conversion rate of 53.2992 shares of the Corporation's Class A common stock per $1,000 principal amount of the Convertible Notes, which is equivalent to an initial conversion price of approximately $18.76. In accordance with ASC 260, the shares of the Corporation's Class A common stock issuable upon conversion of the Convertible Notes is included in the calculation of diluted EPS to the extent that the conversion value of the securities exceeds the principal amount. For diluted EPS purposes, the number of shares of the Corporation's Class A common stock that is necessary to settle such excess is considered issued. For the year ended December 31, 2013, the conversion value did not exceed the principal amount and therefore the conversion effect was not included in the computation of diluted EPS because it was antidilutive under the treasury method.
	As described in Note 21, the Company also entered into a warrant transaction whereby the Company sold to the counterparties warrants to purchase shares of the Corporation's Class A common stock. For the year ended December 31, 2013, the warrants were not included in the computation of diluted EPS because they were antidilutive under the treasury method.
	Additionally, as discussed in Note 2, the Existing Unit Holders also entered into an Exchange Agreement under which they (or certain permitted transferees thereof) have the right, from and after the first anniversary of the date of the closing of the IPO, (subject to the terms of the Exchange Agreement as described therein) to exchange their Holding Units for shares of the Corporation’s Class A common stock on a one-for-one basis at fair value, subject to customary conversion rate adjustments for stock splits, stock dividends and reclassifications. These shares were also excluded from the computation of dilutive EPS because they were anti-dilutive under the treasury method. During the years ended December 31, 2013 and 2012, certain members of Holdings exchanged 10.1 million and 10.8 million of their Holding Units, on a one-for-one basis, for shares of Class A common stock of the Corporation under the Exchange Agreement (see Note 15).
	The following is a reconciliation of the numerator and denominator used in the basic and diluted EPS calculations, with amounts in thousands except per share data:
		Year Ended December 31, 2013		Year Ended December 31, 2012		Year Ended December 31, 2011
	Basic and diluted net income per share:
	Numerator
	Net income available to holders of Class A common stock	$	14,832	$	8,958	$	12,736
	Earnings allocated to participating securities	—		—		—
	Earnings available for common stockholders	$	14,832	$	8,958	$	12,736
	Denominator for basic net income per share of Class A common stock
	Weighted average shares of Class A common stock	32,789		24,086		16,567
	Add dilutive effect of the following:
	Stock options	616		—		—
	Lucid contingently issuable shares	552		—		—
	Convertible note hedges	—		—		—
	Warrants	—		—		—
	Assumed conversion of Holding Units for	—		—		—
	Class A common stock
	Dilutive weighted average shares of Class A common stock	33,957		24,086		16,567
	Basic income per share of Class A common stock	$	0.45	$	0.37	$	0.77
	Diluted income per share of Class A common stock	$	0.44	$	0.37	$	0.77

Related_Party_Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2013
Related Party Transactions [Abstract]	'
Related Party Transactions	'
	Related Party Transactions
	Amounts receivable from, and payable to, related parties are set forth below, with amounts in millions:
		December 31, 2013		December 31, 2012
	Receivables
	Advances to partners	$	0.9	$	—
	Advances to employees	0.8		0.9
		$	1.7	$	0.9
	Payables
	Guaranty agreements	$	8.4	$	9
	Employees	0.7		0.3
	Shareholders with greater than 5% ownership in the Company	0.2		0.7
	Due to Lucid non-controlling members in connection with the allocation of net income to Lucid non-controlling members for services provided	9.8		—
	Due to Lucid non-controlling members in connection with trade settlements	0.2		9.6
	Notes payable to Lucid non-controlling members in connection with the Acquisition	9.8		22.9
	Tax receivable agreement	150.3		100.8
	Follow-on Payment	3.7		—
		$	183.1	$	143.3
	The Company has advanced funds for withholding taxes for several partners. The outstanding balance as of December 31, 2013, included in the table above, is included in Accounts receivable, net in the consolidated statements of financial condition.
	The Company has advanced funds to several employees. The outstanding balances as of December 31, 2013 and 2012, included in the table above, are included in Accounts receivable, net in the consolidated statements of financial condition.
	Customer account liabilities included in the consolidated statements of financial condition include balances for employees and shareholders with greater than 5% ownership in the Company.
	UK is party to an arrangement with Global Finance Company (Cayman) Limited, (“Global Finance”), and Master Capital Group, S.A.L. (“Master Capital”). A shareholder of the Company beneficially owns more than 90% of the equity of Global Finance and Master Capital. Pursuant to such arrangement, Global Finance and Master Capital are permitted to use the brand name “FXCM” and our technology platform to act as the Company’s local presence in certain countries in the Middle East and North Africa (“MENA”). UK collects and remits to Global Finance and Master Capital fees and commissions charged by Global Finance and Master Capital to customers in MENA countries. For the years ended December 31, 2013, 2012 and 2011, these fees and commissions were approximately $1.6 million, $2.5 million and $3.5 million, respectively, and are included in the consolidated statements of operations.
	In March 2012, the Company entered into a settlement agreement with the former owners of ODL in connection with the acquisition of ODL by the Company in October 2010. The settlement agreement serves to settle outstanding claims arising out of the acquisition of ODL related to certain warranties and indemnities pursuant to the share and purchase agreement. The settlement to the Company included cash of $1.2 million, return of capital, (i.e., equity interest of Holdings) of $4.0 million, and the forgiveness of the payment of a liability by the Company to the former owners in the amount of $1.4 million. The Company recorded a gain of $1.4 million for the year ended December 31, 2012, included in Other income in the consolidated statements of operations, in connection with this settlement. In addition, the settlement required ODL to establish a collateral account for the benefit of the Company to pay certain outstanding third party claims up to an agreed upon amount. For the year ended December 31, 2013, the Company recorded a net loss of $0.2 million, included in Other income in the consolidated statements of operations, related to this settlement.
	In August 2012, the Company entered into a master guaranty agreement (the “Method Guaranty”) with Method Credit Fund (“Method”), a Cayman Island company, owned by certain directors and shareholders of the Company, including several of the Company’s executive officers. Pursuant to the Method Guaranty, Method unconditionally guaranteed the obligations of certain counterparties that maintained a margin account with the Company. The Method Guaranty required Method to maintain a cash collateral account held by the Company equal to the aggregate amount of margin extended to all counterparties covered by the Method Guaranty. In exchange for this unconditional guaranty, the Company remitted a fee to Method determined on a counterparty by counterparty basis which was agreed upon by the Company, Method and the respective counterparty. The agreement was terminated in November 2013 and upon termination, the aggregate amount of margin extended under the Method Guaranty was reduced to zero. As of December 31, 2012, the aggregate amount of margin extended under the Method Guaranty was $1.1 million. During the years ended December 31, 2013 and 2012, no payments were made by Method to the Company to satisfy a guaranteed counterparty obligation. For the years ended December 31, 2013 and 2012, fees collected from counterparties and subsequently remitted to Method by the Company under the Method Guaranty were not material and are included in Referring broker fees in the consolidated statement of operations. As of December 31, 2012, the Company held cash collateral in the amount of $9.0 million which is included Cash and cash equivalents, held for customers and Customer account liabilities in the consolidated statements of financial condition.
	In November 2013, the Company entered into a master guaranty agreement (the “Monetary Guaranty”) with Monetary Credit Group LLC (“Monetary”), a newly formed Texas limited liability company, owned by certain directors and shareholders of the Company, including several of the Company’s executive officers. Pursuant to the Monetary Guaranty, Monetary unconditionally guarantees the obligations of certain counterparties that maintain a margin account with the Company. The Monetary Guaranty requires Monetary to maintain a cash collateral account held by the Company equal to the aggregate amount of margin extended to all counterparties covered by the Monetary Guaranty. In exchange for this unconditional guaranty, the Company remits a fee to Monetary determined on a counterparty by counterparty basis which is agreed upon by the Company, Monetary and the respective counterparty. The Monetary Guaranty may be terminated by either the Company or Monetary at any time provided that if Monetary elects to terminate there are no guaranteed obligations outstanding.   As of December 31, 2013, the aggregate amount of margin extended under the Monetary Guaranty was $4.5 million. During the year ended December 31, 2013, no payments were made by Monetary to the Company to satisfy a guaranteed counterparty obligation. For the year ended December 31, 2013, fees collected from counterparties and subsequently remitted to Monetary by the Company under the Monetary Guaranty were not material and are included in Referring broker fees in the consolidated statements of operations.
	As of December 31, 2013, the Company held cash collateral in the amount of $8.4 million which is included in Cash and cash equivalents, held for customers and Customer account liabilities in the consolidated statements of financial condition. In January 2014, $2.4 million of the cash collateral was returned to one of the former members of Method and the balance was reduced to $6.0 million.
	Accounts payable and accrued expenses in the consolidated statements of financial condition include a balance of $0.2 million and $9.6 million of advances from certain Lucid non-controlling members in connection with trade settlements as of December 31, 2013 and December 31, 2012, respectively. Accounts payable and accrued expenses also include a balance of $9.8 million and nil related to the Allocation of net income to Lucid members for services provided as of December 31, 2013 and December 31, 2012, respectively (see Note 3).
	Notes payable of $9.8 million and $22.9 million included in the consolidated statements of financial condition as of December 31, 2013 and December 31, 2012, respectively, represent the amount borrowed from the Lucid non-controlling members in connection with the Acquisition (see Notes 5 and 21).
	Other liabilities in the consolidated statements of financial condition include the Follow-on Payment of $3.7 million and nil as of December 31, 2013 and December 31, 2012, respectively, related to the Faros acquisition (see Note 5).
	Exchange Agreement
	As discussed in Note 2, Existing Unit Holders entered into an Exchange Agreement under which they (or certain permitted transferees thereof) have the right, from and after the first anniversary of the date of the closing of the IPO (subject to the terms of the exchange agreement as described therein), to exchange their Holding Units for shares of the Corporation’s Class A Common Stock on a one-for-one basis at fair value, subject to customary conversion rate adjustments for stock splits, stock dividends and reclassifications. During the years ended December 31, 2013 and 2012, certain members of Holdings exchanged 10.1 million and 10.8 million, respectively of their Holding Units, on a one-for-one basis, for shares of Class A common stock of the Corporation under the Exchange Agreement.
	Payments under Tax Receivable Agreement
	As discussed in Note 2, the Corporation entered into a tax receivable agreement with the Existing Unit Holders. The aggregate amounts due under the tax receivable agreement were $150.3 million and $100.8 million as of December 31, 2013 and 2012, respectively. Amounts due under the tax receivable agreement become payable upon the realization of the tax benefit by the Corporation. During the years ended December 31, 2013 and 2012, the Corporation made payments of $3.8 million and nil, respectively, to Existing Unit Holder related to the tax receivable agreement.

StockBased_Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Stock-Based Compensation	'
	Stock-Based Compensation
	The Company has a long term incentive plan (the “LTIP”) that provides for the grant of stock options to purchase shares of the Corporation’s Class A common stock to its employees (“Employee Stock Options”) and the independent members of the board of directors (“Independent Directors Options”) (collectively, the “Stock Options”). The Employee Stock Options have a contractual term of seven years and a four-year graded vesting schedule. The Independent Directors Options also have a seven-year contractual term but cliff vest on the first anniversary after the grant date. Under the terms of the LTIP, the Company may issue new shares or treasury shares upon share option exercise.
	During the year ended December 31, 2013, the Company granted 105,636 Independent Director Options and 426,000 Employee Stock Options to purchase shares of the Corporation’s Class A common stock to employees. During the year ended December 31, 2012, the Company granted 109,488 Independent Director Options and 725,000 Employee Stock Options to purchase shares of the Corporation’s Class A common stock to employees.
	The following table summarizes the Company's stock options activity as of December 31, 2013 and changes for the year then ended:
	Options	Shares			Weighted-Average Exercise Price				Weighted-Average Remaining Contractual Term
	Outstanding at January 1, 2013	9,178,128			$	13.37			2.1
	Granted	531,636			$	14.87
	Exercised	(1,702,714	)		$	13.21
	Forfeited or expired	(399,250	)		$	13.78
	Outstanding as of December 31, 2013	7,607,800			$	13.48			4.3
	Vested or expected to vest at December 31, 2013	7,485,369			$	13.49			4.3
	Exercisable as of December 31, 2013	4,445,164			$	13.77			4
	The weighted-average grant date fair value of options granted during the years 2013, 2012, and 2011 was $5.67, $3.55 and $4.26, respectively. As of December 31, 2013, the weighted average period over which compensation cost on non-vested Stock Options is expected to be recognized is 1.6 years and the unrecognized expense is $12.9 million. The Company had 6,308,628 and 2,046,250 vested stock options under the LTIP during the years ended December 31, 2013 and 2012, respectively. The fair value of the options vested under the LTIP was $32.4 million and $21.3 million during the years ended December 31, 2013 and 2012, respectively.
	Stock-based compensation before income taxes included in Compensation and benefits in the consolidated statements of operations was $10.4 million, $9.8 million and $9.1 million for the years ended December 31, 2013, 2012 and 2011, respectively, for the Employee Stock Options. Stock-based compensation before income taxes included in Compensation and benefits in the consolidated statements of operations was $0.4 million for each year ended December 31, 2013, 2012 and 2011, respectively, for the Independent Directors. The total compensation cost capitalized and included in Office, communication and computer equipment, net, in the consolidated statements of financial condition was $1.4 million for the years ended December 31, 2013 and 2012. The total compensation cost capitalized and included in Office, communication and computer equipment, net in the consolidated statements of financial condition was $1.1 million for the year ended December 31, 2011.
	In arriving at stock-based compensation expense, the Company estimates the number of stock-based awards that will be forfeited due to employee turnover. The Company's forfeiture assumption is based primarily on its turn-over historical experience. If the actual forfeiture rate is higher than the estimated forfeiture rate, then an adjustment will be made to increase the estimated forfeiture rate, which will result in a decrease to the expense recognized in the Company's financial statements. If the actual forfeiture rate is lower than the estimated forfeiture rate, then an adjustment will be made to lower the estimated forfeiture rate, which will result in an increase to expense recognized in the Company's financial statements. The expense the Company recognizes in future periods will be affected by changes in the estimated forfeiture rate and may differ significantly from amounts recognized in the current period.
	Cash proceeds received from the exercise of Stock Options and the income tax benefits realized from the exercise of Stock Options were $22.5 million and $1.5 million, respectively, for the year ended December 31, 2013. The Company did not have any cash proceeds or income tax benefits realized from the exercise of Stock Options for the years ended December 31, 2012 and 2011.
	Valuation Assumptions
	Calculating the fair value of Employee Stock Options requires estimates and significant judgment. The Company uses the Black-Scholes option pricing model to estimate the fair value of its employee stock options, consistent with the provisions of ASC 718. The fair value of the Stock Options grant is estimated on the date of the grant using the Black-Scholes option pricing model, and is not remeasured as a result of subsequent stock price fluctuations. Options granted to the Company's independent directors are considered options granted to employees under ASC 718 as defined therein.
	Assumptions used in the Black Scholes valuation model were as follows:
		Employee Stock Options											Independent Directors Options
		For the Years Ended											For the Years Ended
		2013				2012				2011			2013			2012			2011
	Expected term in years	4.75				4.75				4.75			4			4			N/A
	Risk-free interest rate	1.06		%		0.71		%		0.96		%	0.63		%	0.6		%	N/A
	Expected volatility	51		%		52		%		56		%	54		%	63		%	N/A
	Dividend yield	1.55		%		2.48		%		2.24		%	2.05		%	2.4		%	N/A
	Estimated fair value at grant date	$	6.02			$	3.47			$	4.26		$	4.26		$	4.11		N/A
	Expected term for the Employee Stock Options and Independent Directors Options is based on the simplified method outlined in ASC 718. In accordance with ASC 718, options are considered to be exercised halfway between the average vesting date and the contractual term of each option grant. The simplified method is applicable for “plain vanilla” stock options, as defined in ASC 718, only if the Company does not have sufficient historical data upon which to estimate an expected term. Given that the Corporation’s Class A common stock has been publicly traded for approximately three years, the Company believes that the simplified method is an applicable methodology to estimate the expected term of the options as of the grant date.
	The risk free interest rates for the Employee Stock Options and Independent Directors Options are based on U.S. Treasury instruments whose terms are consistent with the expected lives of the Stock Options.
	Expected volatility is based on a weighing of the historical and implied volatilities of the Company and for a set of public guideline companies deemed comparable to it. The guideline companies selected operate in a similar industry, pursue similar market opportunities, and are subject to similar risks of the Company. Changes in the subjective assumptions required in the valuation models may significantly affect the estimated value of the Company's Stock Options, the related stock-based compensation expense and, consequently, its results of operations and comprehensive income.
	The dividend yield is determined based on the Company's expected dividend payouts.
	The LTIP also provides for other stock based awards (“Other Equity Awards”) which may be granted by the Company’s Executive Compensation Committee (the “Committee”). Pursuant to the terms of the LTIP, the Committee may grant Other Equity Awards that are valued in whole or in part by reference to or that are otherwise based on the fair market value of the Corporation's Class A common stock. The Company did not grant any Other Equity Awards during the year ended December 31, 2013. During the year ended December 31, 2012, the Company granted 945,847 of the Corporation's Class A common stock with a per share fair market value of $11.76 as Other Equity Awards. The Other Equity Awards were fully vested at the date of the grant. Other equity awards compensation expense included in Compensation and benefits in the consolidated statements of operations was nil and $11.1 million for the years ended December 31, 2013 and 2012, respectively.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Stockholders' Equity	'
	Stockholders’ Equity
	Refer to the description of the Reorganization and IPO as described in Note 2 for further information regarding the current capital structure of the Company.
	The Corporation’s authorized capital stock consists of 3,000,000,000 shares of Class A common stock, par value $.01 per share, 1,000,000 shares of Class B common stock, par value $.01 per share, and 300,000,000 shares of preferred stock, par value $.01 per share.
	Class A Common Stock Repurchase Program
	On May 17, 2011 and October 17, 2011, the Company’s Board of Directors approved the repurchase of $30.0 million and $20.0 million of its Class A common stock (the “Stock Repurchase Program”), respectively. On November 7, 2012, the Board of Directors approved a $30.0 million increase in the Stock Repurchase Program for an aggregate of $80.0 million. Purchases under the Stock Repurchase Program may be made from time to time in the open market and in privately negotiated transactions. Under the Stock Repurchase Program, there is no expiration date or other restrictions limiting the period over which the Company can make its share repurchase. The Stock Repurchase Program will expire only when and if the Company has repurchased $80.0 million of its shares under this program. Under the Stock Repurchase Program, repurchased shares are retired and returned to unissued stock. The size and timing of these purchases are based on a number of factors, including price, business and market conditions.
	During the year ended December 31, 2013, the Company repurchased and retired 1,815,800 shares of its Class A common stock, at an average price of $15.46 per share, for approximately $28.1 million pursuant to the trading program under Rule 10b5-1 of the Securities Exchange Act of 1934, as amended. The following table presents the changes in the Company’s Class A common stock shares outstanding during the year ended December 31, 2013, with amounts in thousands:
	Class A Common Stock	As of
		December 31, 2013
	Balance at January 1, 2013	34,684
	Issued	—
	Repurchased	(1,816	)
	Exchange of Holdings units into Class A common stock	10,094
	Stock options exercised	1,703
	Balance at December 31, 2013	44,665
	As of December 31, 2013 and 2012, there were 41 and 43 shares of Class B common stock issued and held by the members of Holdings, respectively.
	Holders of shares of our Class A common stock and Class B common stock vote together as a single class on all matters presented to our stockholders for their vote or approval, except as otherwise required by applicable law.
	Class A Common Stock
	Holders of shares of the Corporation’s Class A common stock are entitled to one vote for each share held of record on all matters submitted to a vote of stockholders. Holders of shares of Class A common stock are entitled to receive dividends when and if declared by the Corporation’s board of directors out of funds legally available therefore, subject to any statutory or contractual restrictions on the payment of dividends and to any restrictions on the payment of dividends imposed by the terms of any outstanding preferred stock. Upon dissolution or liquidation or the sale of all or substantially all of the Corporation’s assets, after payment in full of all amounts required to be paid to creditors and to the holders of preferred stock having liquidation preferences, if any, the holders of shares of Class A common stock will be entitled to receive pro rata the Corporation’s remaining assets available for distribution. Holders of shares of Class A common stock do not have preemptive, subscription, redemption or conversion rights.
	Class B Common Stock
	Each holder of the Corporation’s Class B common stock is entitled, without regard to the number of shares of Class B common stock held by such holder, to one vote for each Holding Unit in Holdings held by such holder. The unit holders of Holdings collectively have a number of votes in the Corporation that is equal to the aggregate number of Holding Units that they hold. Holders of our Class B common stock do not have any right to receive dividends or to receive a distribution upon a liquidation or dissolution of the Corporation.

Employee_Benefit_Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]	'
Employee Benefit Plan	'
	Employee Benefit Plan
	The Company maintains a defined contribution employee profit-sharing and savings 401(k) plan for all eligible full time employees. The Company was not required to and made no contributions to the plan for the years ended December 31, 2013, 2012 and 2011.

Net_Capital_Requirements

Net Capital Requirements	12 Months Ended
	Dec. 31, 2013
Banking and Thrift [Abstract]	'
Net Capital Requirements	'
	Net Capital Requirements
	Our regulated entities are subject to minimum capital requirements in their respective jurisdictions. The minimum capital requirements of the entities below may effectively restrict the payment of cash distributions by the subsidiaries. The tables below present the capital, as defined by the respective regulatory authority, the minimum capital requirement and the excess capital for US, HK, UK, Australia, ODL, FSL, FXCMJ, Lucid LLP and Faros as of December 31, 2013 and 2012, with amounts in millions:
		December 31, 2013
		US		HK		UK		Australia		ODL		FSL		FXCMJ		Lucid LLP		Faros
	Capital	$	64.2	$	33.6	$	86	$	4.7	$	18.4	$	34.8	$	36.3	$	41.8	$	0.1
	Minimum capital requirement	27.1		12.3		24.7		0.4		6.9		8.2		5.6		4.2		—
	Excess capital	$	37.1	$	21.3	$	61.3	$	4.3	$	11.5	$	26.6	$	30.7	$	37.6	$	0.1
		December 31, 2012
		US		HK		UK		Australia		ODL		FSL		FXCMJ
	Capital	$	53.5	$	22.7	$	73.1	$	4.2	$	14.1	$	30.7	$	33.5
	Minimum capital requirement	26.1		8.1		17.4		1.2		4.4		4.4		5.6
	Excess capital	$	27.4	$	14.6	$	55.7	$	3	$	9.7	$	26.3	$	27.9

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Commitments and Contingencies
	Operating Lease Commitments
	The Company leases office space and equipment under operating leases. Some of the lease agreements contain renewal options ranging from 3 to 5 years at prevailing market rates. The leases for the office facilities are subject to escalation factors primarily related to property taxes and building operating expenses. Future minimum lease payments under non-cancelable operating leases with terms in excess of one year are as follows as of December 31, 2013, with amounts in thousands:
	Year Ending December 31,	As of
		December 31, 2013
	2014	$	7,186
	2015	5,847
	2016	4,685
	2017	3,807
	2018	3,612
	Thereafter	23,240
		$	48,377
	The aggregate operating lease expense, net of sublease income, included in General and administrative expense in the consolidated statements of operations, for the years ended December 31, 2013, 2012 and 2011, was $8.3 million, $7.9 million and $8.9 million, respectively. There was no sublease income for the years ended December 31, 2013 and 2012 and sublease income was not material for the year ended Decembers 31, 2011. For the years ended December 31, 2013 and 2012, there were no sublease commitments. The Company leases its corporate office location under an operating lease agreement expiring in May 2026.
	Capital Lease Commitments
	The Company leases office equipment under capital leases. Interest paid as part of our capital lease obligation was not material for the years ended December 31, 2013, 2012, and 2011, respectively. The capital leases expire in 2015. Future minimum lease payments for capital leases are not material for the years 2014 and 2015.
	Other
	The Company holds an interest in an inactive entity that formerly provided online FX educational services ("Online Courses"). Online Courses meets the definition of a VIE under ASC 810 and the Company is considered the primary beneficiary. The members who own the remaining interest in Online Courses have a put option to sell their interest to the Company upon a change in control of Holdings. A change in control occurs when the number of Holdings units held by unit holders as of the date of the Online Courses operating agreement, November 17, 2008, ceases to make up at least 50% of the voting or vested economic interest securities of Holdings. Under U.S. GAAP, the value of the put option is recognized upon the change in control and the exercise of the put option.
	Assuming both a change in control and the exercise of the put option at December 31, 2013, the Company would have been obligated to purchase the remaining interest for approximately $3.3 million. Pursuant to the terms of the Online Courses operating agreement, the put option payment accretes interest at a rate of 15% per annum. Based on the status (inactive and no assets) of Online Courses, a put option payment would most likely result in a charge to earnings.

Debt

Debt	12 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Debt	'
	Debt
	Credit Agreement
	On December 19, 2011, Holdings entered into a three year credit agreement (the “Credit Agreement”) with a syndicate of financial institutions. The Credit Agreement provided for a revolving credit facility of up to $75.0 million. The credit facility is guaranteed by certain subsidiaries of Holdings and is secured by a pledge of all of the equity interests in certain of Holdings’ domestic subsidiaries and 65% of the voting equity interests in certain of its foreign subsidiaries.
	On November 8, 2012, Holdings entered into an amendment to the Credit Agreement (the “2012 Amendment”). The 2012 Amendment provided Holdings with the ability to increase the credit facility during the term of the Credit Agreement up to a maximum of $175.0 million. Additionally, the 2012 Amendment modified certain terms of the Credit Agreement, among other things, to provide additional flexibility regarding financing and investment initiatives. Simultaneously, on November 8, 2012, Holdings received additional commitments from a group of financial institutions, both new and existing lenders, and increased the credit facility to $155.0 million.
	On November 15, 2013, Holdings entered into an amendment to the Credit Agreement (the “2013 Amendment”). The 2013 amendment extended the final maturity date of the credit facility to December 2016 and provided Holdings with the ability to increase the credit facility during the term of the Credit Agreement up to a maximum of $250.0 million. Additionally, the 2013 Amendment modified certain terms of the Credit Agreement, among other things, to provide additional flexibility regarding financing and investment initiatives. Simultaneously, on November 15, 2013, Holdings received additional commitments from existing lenders and increased the credit facility to $205.0 million.
	As of December 31, 2013 and 2012, Holdings’ outstanding balance under the Credit Agreement was nil and $85.0 million, respectively.
	Under the terms of the Credit Agreement, loans will bear interest at either a Eurodollar Rate or a Base rate (as defined below), at Holdings’ election, plus an applicable margin, based on Holdings’ leverage ratio. In addition, Holdings must pay an annual commitment fee based on Holdings’ leverage ratio on the undrawn commitments under the Credit Agreement. The applicable margin and commitment fees are set forth in the table below:
	Consolidated Leverage Ratio		Commitment Fee			Applicable Margin for Eurodollar Loans		Applicable Margin for Base Rate Loans
	Less than .50 to 1.00		0.25	%		1.75	%	0.75	%
	Greater than or equal to 0.50 to 1.00 but less than 1.00 to 1.00		0.3	%		2	%	1	%
	Greater than or equal to 1.00 to 1.00 but less than 1.50 to 1.00		0.35	%		2.25	%	1.25	%
	Greater than or equal to 1.50 to 1.00, but less than 2.00 to 1.00		0.4	%		2.5	%	1.5	%
	Greater than or equal to 2.00 to 1.00		0.45	%		2.75	%	1.75	%
	The Base Rate means for any day a fluctuating rate per annum equal to the highest of (a) the Federal Funds Rate, as defined in the Credit Agreement, plus 0.5%, (b) the rate of interest in effect for such day as publicly announced from time to time by the administrative agent, Bank of America, N.A., as its prime rate, and (c) the Eurodollar Rate plus 1.00%. The Eurodollar Rate means the rate per annum equal to (i) the British Bankers Association LIBOR Rate, or (ii) if such rate is not available, the rate per annum determined by the administrative agent.
	Interest expense related to borrowings under the Credit Agreement, including the amortization of debt financing costs, included in Interest on borrowings in the consolidated statements of operations was $1.4 million, $1.2 million and nil for the years ended December 31, 2013, 2012 and 2011, respectively.
	Pursuant to covenants in the Credit Agreement, Holdings’ is required to maintain: excess net capital amount of 125% of adjusted net capital required to be maintained as of the last day of any fiscal quarter for US and UK (see Note 19), Consolidated Interest Coverage Ratio and Consolidated Leverage Ratio, as defined in the Credit Agreement, of 4.00 to 1.00 and 2.50 to 1.00, respectively, as of the last day of any fiscal quarter, Net Unhedged Exposure, as defined in the Credit Agreement, of less than 20% of total assets of Holdings and its subsidiaries, and Net Unhedged Non-FX Exposure, as defined in the Credit Agreement, of less than 10% of total assets of Holdings and its subsidiaries. In addition, the Credit Agreement contains certain customary covenants as well as certain customary events of default. As of December 31, 2013, Holdings was in compliance with all material covenants.
	During the year ended December 31, 2013, the weighted average dollar amount of borrowings related to the Credit Agreement was $34.9 million and the weighted average interest rate was 2.4%. During the year ended December 31, 2012, the weighted average dollar amount of borrowings related to the Credit Agreement was $41.2 million and the weighted average interest rate was 2.1%. For the year ended December 31, 2011 there were no amounts outstanding under the Credit Agreement.
	Senior Convertible Notes due 2018
	In June 2013, the Corporation issued $172.5 million principal amount of 2.25% Convertible Notes maturing on June 15, 2018 and received net proceeds of $166.5 million, after deducting the initial purchasers' discount and offering expenses. The Convertible Notes pay interest semi-annually on June 15 and December 15 at a rate of 2.25% per year, commencing December 15, 2013. The indenture governing the Convertible Notes does not prohibit the Company from incurring additional senior debt or secured debt, nor does it prohibit any of its subsidiaries from incurring additional liabilities.
	The Convertible Notes will be convertible at an initial conversion rate of 53.2992 shares of the Corporation's Class A common stock per $1,000 principal amount of the Convertible Notes, which is equivalent to an initial conversion price of approximately $18.76. In addition, following certain corporate transactions that occur prior to the maturity date, the Corporation will, in certain circumstances, increase the conversion rate for a holder that elects to convert its Convertible Notes in connection with such corporate transaction. Upon conversion, the Corporation will deliver cash up to the principal amount. With respect to any conversion value in excess of the principal amount, the Corporation will deliver shares of its Class A common stock (unless it elects to deliver cash in lieu of all or a portion of such shares).
	Holders may convert their notes at their option prior to the close of business on the business day immediately preceding March 15, 2018, only under the following circumstances:
	•	during any fiscal quarter commencing after the fiscal quarter ending on September 30, 2013 (and only during such fiscal quarter), if the last reported sale price of the Corporation's Class A common stock for at least 20 trading days (whether or not consecutive) during the period of 30 consecutive trading days ending on the last trading day of the immediately preceding fiscal quarter is greater than or equal to 130% of the applicable conversion price on each applicable trading day;
	•	during the five business day period immediately after any five consecutive trading day period (the “measurement period”) in which the “trading price” (as defined in the offering circular) per $1,000 principal amount of notes for each trading day of such measurement period was less than 98% of the product of the last reported sale price of the Corporation's Class A common stock and the applicable conversion rate on such trading day;
	•	upon the occurrence of specified corporate events; or
	•	on or after March 15, 2018 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert their notes at any time.
	In addition, if the Company undergoes a fundamental change (as defined in the offering circular), holders may, subject to certain conditions, require the Corporation to repurchase their notes for cash at a price equal to 100% of the principal amount of the notes to be purchased, plus accrued and unpaid interest.
	Convertible Note Hedges
	In connection with the offering of the Convertible Notes, the Company entered into privately negotiated convertible note hedge transactions with certain counterparties (the “Convertible Note Hedge Transaction”). The Convertible Note Hedge Transactions will cover, subject to customary anti-dilution adjustments, the number of shares of the Corporation's Class A common stock that will initially underlie the Convertible Notes. Concurrently with entering into the Convertible Note Hedge Transaction, the Company also entered into a separate, privately negotiated warrant transaction (the “Warrant Transaction”) with the same counterparties, whereby the Company sold to the counterparties warrants to purchase, subject to customary anti-dilution adjustments, up to the same number of shares of the Corporation's Class A common stock as in the Convertible Note Hedge Transaction. The strike price of the Warrant Transaction will initially be $21.24 per share of the Corporation's Class A common stock. Subject to certain conditions, the Company may settle the warrants in cash or on a net-share basis.
	The Convertible Note Hedge Transaction and the Warrant Transaction have the effect of increasing the effective conversion price of the Convertible Notes to $21.24 per share. The cost of the Convertible Note Hedge Transaction and the proceeds from the Warrant Transaction was $29.1 million and $18.6 million, respectively. In accordance with ASC 815, the Company recorded the cost of the Convertible Note Hedge Transaction and the proceeds from the Warrant Transaction to additional-paid-in-capital in stockholders' equity in the consolidated statements of financial condition and the recorded values will not be adjusted for subsequent changes in their respective fair values.
	The Convertible Note Hedge Transaction and the Warrant Transaction are separate transactions, in each case, entered into by the Company with certain counterparties, and are not part of the terms of the Convertible Notes and will not affect any holder's right under the Convertible Notes. Holders of the Convertible Notes will not have any rights with respect to the Convertible Hedge Transaction or the Warrant Transaction.
	Under ASC 470 Debt ("ASC 470"), an entity must separately account for the liability and equity components of the convertible debt instruments (such as the Convertible Notes) that may be settled entirely or partially in cash upon conversion in a manner that reflects the issuer's economic interest cost. The effect of ASC 470 on the accounting for the Convertible Notes is that the fair value of the equity component is included in the additional paid-in capital section of stockholders' equity in the Company's consolidated statements of financial condition and the principal amount of the Convertible Notes is reduced by original issue discount to reflect the Convertible Notes fair value at issuance. At issuance, the equity component of the Convertible Notes was valued at $29.1 million and the Convertible Notes were valued at $144.1 million consisting of $172.5 million of principal net of original issuance discount of $29.1 million. The original issue discount will be amortized over the life of the Convertible Notes using the effective interest rate of 6.2%.
	The balances of the liability and equity components as of December 31, 2013, were as follows, with amounts in thousands:
			December 31, 2013
	Liability component - principal		$	172,500
	Deferred bond discount		(26,197		)
	Liability component - net carrying value		$	146,303
	Equity component		$	29,101
	Interest expense related to the Convertible Notes, included in Interest on borrowings in the consolidated statements of operations was as follows, with amounts in thousands:
			Year Ended December 31, 2013
	Interest expense - stated coupon rate		$	2,232
	Interest expense - amortization of deferred bond discount		2,904
	Interest expense - amortization of debt issuance cost		699
	Total interest expense - Convertible Notes		$	5,835
	The Company incurred $6.0 million of Convertible Notes issuance cost. Amortization of Convertible Notes issuance costs included in Interest on borrowings in the consolidated statements of operations was $0.7 million for the year ended December 31, 2013. Unamortized Convertible Notes issuance cost was $5.3 million at December 31, 2013 and is included in Other assets in the consolidated statements of financial condition.
	Notes Payable
	As discussed in Note 5, in connection with the acquisition of Lucid, the Company issued to the Lucid sellers 3.5% unsecured promissory notes in the amounts of $71.4 million and $15.8 million maturing on December 21, 2012. On December 21, 2012, the Company repaid $64.0 million of these notes and issued a series of 2.25%, $22.9 million unsecured promissory notes for the balance. The notes were pre-paid on June 6, 2013 with a portion of the proceeds received from the Convertible Notes issued on June 3, 2013. In the second quarter of 2013, the Lucid purchase price was increased by $15.3 million due to the final determination of tax balances at the Acquisition Date adjusted during the measurement period. The Company issued six-month 2.25% unsecured promissory notes to the Lucid sellers for the purchase price increase which matured on December 21, 2013. In satisfaction of the matured notes, the Company repaid $5.5 million and issued a series of 2.25% unsecured promissory notes to the Lucid sellers for the balance of $9.8 million with a maturity date of June 6, 2014.

Derivative_Financial_Instrumen

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivative Financial Instruments	'
	Derivative Financial Instruments
	Derivative financial instruments are accounted for in accordance with ASC 815 and are included in Due from/to brokers in the consolidated statements of financial condition. The Company recognizes all derivative financial instruments in the consolidated statements of financial condition as either assets or liabilities at fair value. The Company has master netting agreements with its respective counterparties under which derivative financial instruments are presented on a net-by counterparty basis in accordance with ASC 210 and ASC 815. The Company enters into futures contracts to (i) economically hedge the open customer contracts on its CFD business and (ii) hedge trading in its electronic market making and institutional foreign exchange spot and futures markets. Futures contracts are exchanged traded contracts to either purchase or sell a specific asset at a specified future date for a specified price. Gains or losses on futures contracts related to the Company’s CFD business are included in Retail trading revenue and gains or losses on hedge trading in its electronic market making and institutional foreign exchange spot and futures markets are included in Institutional trading revenue in the consolidated statements of operations.
	The following tables present the gross and net fair values of the Company's derivative transactions and the related offsetting amounts permitted under ASC 210 and ASC 815, as of December 31, 2013 and December 31, 2012. Under ASC 210, gross positive fair values are offset against gross negative fair values by counterparty pursuant to enforceable master netting agreements, with amounts in thousands:
		Derivatives Classified
		in Due from/to brokers
		December 31, 2013
		Assets			Liabilities			Net
	Gross fair values	$	84		$	(2,404	)	$	(2,320	)
	Netting agreements	(84		)	84			—
	Net fair values	$	—		$	(2,320	)	$	(2,320	)
		Derivatives Classified
		in Due from/to brokers
		December 31, 2012
		Assets			Liabilities			Net
	Gross fair values	$	520		$	(265	)	$	255
	Netting agreements	(265		)	265			—
	Net fair values	$	255		$	—		$	255
	For the years ended December 31, 2013, 2012 and 2011, total revenues of $489.6 million, $417.3 million, and $415.6 million in the consolidated statements of operations included net losses of $74.3 million, $46.3 million and $8.8 million respectively, related to derivative financial instrument transactions. The net notional value of the derivative financial instruments was $159.9 million and $119.5 million as of December 31, 2013 and 2012 respectively.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	Fair Value Measurements
	The following table presents the Company's assets and liabilities that are measured at fair value on a recurring basis and the related hierarchy levels, with amounts in thousands:
		Fair Value Measurements on a Recurring Basis
		As of December 31, 2013
		Quoted Prices in Active Markets for Identical Assets (Level I)		Significant Observable Inputs (Level II)		Significant Unobservable Inputs (Level III)			Total
	Financial Assets:
	Cash and cash equivalents	$	365,245	$	—	$	—		$	365,245
	Cash and cash equivalents, held for customers	1,190,880		—		—			1,190,880
	Total assets	$	1,556,125	$	—	$	—		$	1,556,125
	Financial Liabilities:
	Customer account liabilities	$	1,190,880	$	—	$	—		$	1,190,880
	Due to brokers- open futures contracts	2,320		—		—			2,320
	Follow-on Payment	—		—		3,672			3,672
	Total liabilities	$	1,193,200	$	—	$	3,672		$	1,196,872
		Fair Value Measurements on a Recurring Basis
		As of December 31, 2012
		Quoted Prices in Active Markets for Identical Assets (Level I)		Significant Observable Inputs (Level II)		Significant Unobservable Inputs (Level III)			Total
	Financial Assets:
	Cash and cash equivalents	$	272,332	$	—	$	—		$	272,332
	Cash and cash equivalents, held for customers	1,190,762		—		—			1,190,762
	Due from brokers- open futures contracts	255		—		—			255
	Total assets	$	1,463,349	$	—	$	—		$	1,463,349
	Financial Liabilities:
	Customer account liabilities	$	1,190,762	$	—	$	—		$	1,190,762
	Total liabilities	$	1,190,762	$	—	$	—		$	1,190,762
	Cash and cash equivalents and cash and cash equivalents, held for customers are deemed to be Level I financial assets. Open futures contracts included in Due from brokers and Due to brokers, are classified as Level I financial assets and liabilities, respectively, as they are actively traded and valued at their quoted market prices.
	The following table presents the carrying value, fair value and fair value hierarchy category of certain financial instruments that are not measured at fair value in the consolidated statements of financial condition, with amounts in thousands:
		As of December 31, 2013				Fair Value Measurements using:
		Carrying Value		Fair Value		Quoted Prices in Active Markets for Identical Assets (Level I)			Significant Observable Inputs (Level II)		Significant Unobservable Inputs (Level III)
	Financial Assets:
	Due from brokers- unsettled spot FX	$	5,450	$	5,450	$	5,450		$	—	$	—
	Equity method investments	9,793		13,504		—			—		13,504
	Notes receivable	11,942		11,942		—			—		11,942
	Total assets	$	27,185	$	30,896	$	5,450		$	—	$	25,446
	Financial Liabilities:
	Due to brokers- unsettled spot FX	$	6,332	$	6,332	$	6,332		$	—	$	—
	Notes payable	9,800		9,800		—			—		9,800
	Senior convertible notes	146,303		149,418		—			149,418		—
	Total liabilities	$	162,435	$	165,550	$	6,332		$	149,418	$	9,800
	Other assets, excluding equity method investments and notes receivable, are carried at contracted amounts, which approximate fair value. Equity method investments are carried at cost. Fair value is based on a DCF analysis. Notes receivables are carried at contracted amounts which approximate fair value, as the fair value is based on an assessment of the underlying collateral. Notes payable are carried at contracted amounts, which approximate fair value based on the relatively short amount of time until maturity. Senior convertible notes are carried at contractual amounts. The fair value of the Senior convertible notes are based on similar recently executed transactions and market price quotations (where observable) obtained from independent brokers.
	The following table reconciles the ending balances of liabilities classified as Level III and identifies the total gains (losses) the Company recognized during the year ended December 31, 2013 on such liabilities that were included in the consolidated statements of financial condition as of December 31, 2013, respectively with amounts in thousands:
		Beginning Balance		Additions		Net Unrealized/Realized (Gains) Losses			Total
	Follow-on Payment	$	—	$	10,631	$	(6,959	)	$	3,672
	Total Level III liabilities	$	—	$	10,631	$	(6,959	)	$	3,672
	As of December 31, 2013, the Follow-on Payment was valued using significant unobservable inputs based on a multiple of Faros' 2014 EBITDA. A hypothetical 10% change (increase or decrease) in either the multiple or EBITDA used in the calculation would result in approximately a 24% increase or decrease in the fair value of the Follow-on Payment. The net unrealized/realized gains (losses) are included in Other income in the consolidated statements of operations.
	The Company did not have any transfers in or out of Level I, II and III during the year ended December 31, 2013.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Holdings operates in the U.S. as a limited liability company that is treated as a partnership for U.S. federal, state, and local income tax purposes. As a result, Holdings' income from its U.S. operations is not subject to U.S. federal income tax because the income is attributable to its members. Accordingly, the Company’s U.S. tax provision is solely based on the portion of Holdings’ income attributable to the Corporation and excludes the income attributable to other members of Holdings whose income is included in Net income attributable to non-controlling interest in FXCM Holdings, LLC in the consolidated statements of operations.
	In addition to U.S. federal and state income taxes, the Company is subject to Unincorporated Business Tax which is attributable to Holdings' operations apportioned to New York City. The Company’s foreign subsidiaries are also subject to local taxes.
	Income before income taxes, as shown in the consolidated statements of operations, includes the following income components, with amounts in thousands:
		Years Ended December 31,
		2013				2012				2011
	Domestic	$	10,390			$	19,794			$	29,035
	Foreign	41,470				27,670				40,562
		$	51,860			$	47,464			$	69,597
	The provision for income taxes consists of the following, with amounts in thousands:
		Year Ended December 31,
		2013				2012				2011
	Current
	Federal income tax (benefit)	$	(185	)		$	478			$	238
	State and local income tax	682				574				1,384
	Foreign income tax	5,085				764				9,268
	Subtotal	$	5,582			$	1,816			$	10,890
	Deferred
	Federal income tax	$	3,996			$	2,837			$	7,578
	State and local income tax (benefit)	235				(171		)		(1,802		)
	Foreign income tax (benefit)	7,211				4,504				(5,850		)
	Subtotal	$	11,442			$	7,170			$	(74	)
	Total provision for taxes	$	17,024			$	8,986			$	10,816
	The following table reconciles the provision for income taxes to the U.S. federal statutory tax rate:
		Year Ended December 31,
		2013			2012			2011
	Statutory U.S. federal income tax rate	34	%		34	%		34	%
	Income passed through to non-controlling members	(5.4	)		(15.5	)		(13.0	)
	State and local income tax	0.9			1			2.1
	Foreign income tax	(1.4	)		(3.1	)		(0.2	)
	Release of valuation allowance	—			—			(11.8	)
	Non- deductible FCA fine	2			—			—
	Foreign tax credit valuation allowance	3.5			2.5			0.8
	Impact of rate change on deferred tax assets	(0.9	)		—			4
	Other	0.1			—			(0.4	)
	Effective tax rate	32.8	%		18.9	%		15.5	%
	The increase in the effective tax rate for the year ended December 31, 2013 compared to the year ended December 31, 2012 was primarily due to an increase in the Corporation’s ownership in Holdings, a valuation allowance established on the Company's foreign tax credits and the non-deductible FCA penalty the Company accrued. The increase in the Corporation’s ownership in Holdings is due to Holdings' members exchanging their membership units for the Corporation’s Class A common stock. The Company’s effective tax rate increases as additional exchanges occur because the portion of Holdings’ income attributable to the Corporation, and therefore taxable, increases. The effect of Holdings member unit exchanges is partially offset by the Corporation's Class A common stock repurchases. Anytime the Corporation repurchases shares of its Class A common stock, Holdings enters into an equivalent Holdings membership unit transaction with the Corporation. The effect of these repurchases decreases the Corporation’s ownership in Holdings and, accordingly, decreases the portion of Holdings’ income attributable to the Corporation (see Note 4). In addition, the Company’s effective tax rate increased due to the Company earning a higher portion of its income from subsidiaries (primarily Lucid) taxed locally as corporations in their respective foreign jurisdictions in 2013. This increase in tax on foreign sourced income is somewhat offset by a lower statutory tax rate in effect in the U.K. for the years ended December 31, 2013 and 2012. The Company’s effective tax rate for the year ended December 31, 2011 reflects the release of a valuation allowance relating to FXCMJ’s tax loss carryforwards.
	Deferred tax assets and liabilities are determined based on the differences between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. A summary of the tax effects of the temporary differences is as follows, with amounts in thousands:
		Years Ended December 31,
		2013				2012
	Deferred tax assets
	Equity based compensation	$	1,059			$	1,259
	Investment in partnership	178,941				118,327
	Fixed assets	2,279				4,009
	Tax loss carryforwards	25,631				7,761
	Tax credit carryforward/foreign sub income	4,265				2,083
	Japan software	1,516				3,083
	Other	577				140
	Gross deferred tax assets	$	214,268			$	136,662
	Less: valuation allowance	(25,288		)		(8,843		)
	Net deferred tax asset	$	188,980			$	127,819
	Deferred tax liabilities
	Fixed assets	$	4			$	65
	Intangible assets	3,965				6,292
	Goodwill	8,742				12,563
	Software development cost	238				193
	Other	1,232				338
	Gross deferred tax liabilities	$	14,181			$	19,451
	Net deferred tax asset	$	174,799			$	108,368
	The increase in deferred tax assets was primarily driven by the increase in the Corporation’s ownership in Holdings as a result of members of Holdings exchanging their membership units for the Corporation's Class A common stock. As Existing Unit Holders exchange their membership units, the Company records a deferred tax benefit related to Holdings election under Section 754 of the Internal Revenue Code (see Note 2). The increase in net operating loss carryforwards also contributed to the increase.
	The Company assesses available positive and negative evidence to estimate if it is more-likely-than-not to use certain jurisdiction-based deferred tax assets including certain tax credits and net operating loss carryovers. On the basis of this assessment, a valuation allowance of $25.3 million was recorded as of December 31, 2013.
	As of December 31, 2013, the Company has $129.8 million of foreign net operating loss carryforwards. The net operating loss carryforwards have various expiration dates through 2033 with the net operating losses generated by certain of our U.K. subsidiaries having indefinite carryforward periods.
	The tax credit carryforward includes foreign tax credits of $3.6 million that may be carried forward for a period of 10 years and begin to expire in 2021 and unincorporated business tax credits of $0.4 million that may be carried forward for 7 years.
	The Company does not provide for deferred taxes on the excess of the financial reporting over the tax basis in its investments in foreign subsidiaries that are essentially permanent in duration. That excess totaled $28.1 million as of December 31, 2013.
Income tax payable as of December 31, 2013 and 2012 was $1.0 million and $1.2 million, respectively, and is included in accounts payable and accrued expenses in the consolidated statements of financial condition (see Note 13). Tax receivable as of December 31, 2013 and 2012 was $3.9 million and $6.0 million respectively.
The following is a tabular reconciliation of the total amounts of unrecognized tax benefits, with amounts in thousands:
	2013				2012				2011
Unrecognized tax benefits – January 1	$	3,691			$	223			$	—
Gross increases – tax positions in prior period	—				1				44
Gross decreases – tax positions in prior period	(3,445		)		(16		)		—
Gross increases – tax positions in current period	51				3,483				179
Settlement	(114		)		—				—
Lapse of statute of limitations	—				—				—
Unrecognized tax benefits – December 31	$	183			$	3,691			$	223
The Company recognizes interest and penalties related to unrecognized tax benefits within the income tax expense line in the accompanying consolidated statements of operations. Accrued interest and penalties are included within the related tax liability line in the consolidated statements of financial condition. Related to the unrecognized tax benefits noted above, the Company accrued penalties and interest of immaterial amounts during 2013 and 2012.
The Company does not believe that it will have a material increase in its unrecognized tax benefits during the coming year.
The Company is subject to taxation in the U.S. and various states and foreign jurisdictions. As of December 31, 2013, the Company’s tax years for 2010, 2011, and 2012 are subject to examination by the tax authorities. Currently, the Company's 2011 U.S. Federal tax return is under examination. With a few exceptions, as of December 31, 2013, the Company is no longer subject to U.S. federal, state, local, or foreign examinations by tax authorities for years before 2010.

Foreign_Currencies_and_Concent

Foreign Currencies and Concentrations of Credit Risk	12 Months Ended
	Dec. 31, 2013
Foreign Currency [Abstract]	'
Foreign Currencies and Concentrations of Credit Risk	'
	Foreign Currencies and Concentrations of Credit Risk
	Under the agency model, the Company accepts and clears FX spot contracts for the accounts of its customers (see Notes 1 and 3). These activities may expose the Company to off- balance-sheet risk in the event that the customer or other broker is unable to fulfill its contracted obligations and the Company has to purchase or sell the financial instrument underlying the contract at a loss.
	In connection with these activities, the Company executes and clears customers’ transactions involving the sale of foreign currency not yet purchased, substantially all of which are transacted on a margin basis subject to internal policies. Such transactions may expose the Company to off-balance-sheet risk in the event margin deposits are not sufficient to fully cover losses that customers may incur. In the event that a customer fails to satisfy its obligations, the Company may be required to purchase or sell financial instruments at prevailing market prices to fulfill the customer’s obligation.
	The Company controls such risks associated with its customer activities by requiring customers to maintain margin collateral, in the form of cash, in compliance with various internal guidelines. The Company’s trading software technology monitors margin levels on a real time basis and, pursuant to such guidelines, requires customers to deposit additional cash collateral, or to reduce positions, if necessary. The system is designed to ensure that any breach in a customer’s margin requirement as a result of losses on the trading account will automatically trigger a final liquidation, which will execute the closing of all positions. Exposure to credit risk is therefore minimal. Institutional customers are permitted credit pursuant to limits set by the Company’s prime brokers. The prime brokers incur the credit risk relating to the trading activities of these customers in accordance with the respective agreements between such brokers and the Company.
	The Company is engaged in various trading activities with counterparties which include brokers and dealers, futures commission merchants, banks, and other financial institutions. In the event counterparties do not fulfill their obligations, the Company may be exposed to risk. The risk of default depends on the creditworthiness of the counterparty or issuer of the financial instrument. It is the Company’s policy to: (i) perform credit reviews and due diligence prior to conducting business with counterparties; (ii) set exposure limits and monitor exposure against such limits; and (iii) periodically review, as necessary, the credit standing of counterparties using multiple sources of information. The Company’s Due from brokers balance included in the consolidated statements of financial condition was $5.5 million and $8.0 million as of December 31, 2013 and 2012, respectively. As of December 31, 2013, 96.2% of the Company’s Due from brokers balance, included in the consolidated statements of financial condition, was from one large financial institution. As of December 31, 2012, 91.5% of the Company’s Due from brokers balance, included in the consolidated statements of financial condition, was from one large financial institution. Two banks held more than 10.0% each of the Company’s total cash and cash equivalents and cash and cash equivalents, held for customers as of December 31, 2013. Three banks held more than 10.0% each of the Company’s total cash and cash equivalents and cash and cash equivalents, held for customers as of December 31, 2012.

Segments

Segments	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Segments	'
	Segments
	ASC 280, Segment Reporting, establishes standards for reporting information about operating segments. Operating segments are defined as components of an enterprise about which separate financial information is available that is evaluated regularly by the chief operating decision maker, or decision making group, in deciding how to allocate resources and in assessing performance. The Company’s operations relate to FX trading and related services and operate in two segments — retail and institutional, with different target markets and are covered by a separate sales force, customer support and trading platforms. The Company’s segments are organized around three geographic areas. These geographic areas are the United States, Asia and Europe and are based on the location of its customers’ accounts.
	Retail Trading
	The Company operates its retail business whereby it acts as an agent between retail customers and a collection of large global banks and financial institutions by making foreign currency markets for customers trading in foreign exchange spot markets through its Retail Trading business segment. The Retail Trading business segment also includes the Company’s white label relationships, CFDs, payments for order flow and rollovers. In addition, the Retail Trading business segment includes offerings to some of the Company’s smaller retail clients to trade with a dealing desk, or principal model.
	Institutional Trading
	Institutional Trading facilitates spot foreign currency trades on behalf of institutional customers, market making and electronic trading in the institutional foreign exchange spot and futures markets. The facilitation of spot foreign currency trades allows customers to obtain the best execution price from external banks and financial institutions.
	Information concerning the Company’s operations by reportable segment is as follows, with amounts in thousands:
		As of and For the
		Year Ended December 31, 2013
		Retail Trading			Institutional Trading			Corporate			Total
	Total net revenues	$	379,840		$	110,957		$	(1,209	)	$	489,588
	Operating and other expenses	219,016			99,536			119,176			437,728
	Income (loss) before income taxes	$	160,824		$	11,421		$	(120,385	)	$	51,860
	Assets	$	1,622,829		$	417,492		$	183,626		$	2,223,947
		As of and For the
		Year Ended December 31, 2012
		Retail Trading			Institutional Trading			Corporate			Total
	Total net revenues	$	355,282		$	62,033		$	—		$	417,315
	Operating and other expenses	218,018			45,164			106,669			369,851
	Income (loss) before income taxes	$	137,264		$	16,869		$	(106,669	)	$	47,464
	Assets	$	1,556,680		$	381,368		$	127,122		$	2,065,170
		As of and For the
		Year Ended December 31, 2011
		Retail Trading			Institutional Trading			Corporate			Total
	Total net revenues	$	383,356		$	28,908		$	3,314		$	415,578
	Operating and other expenses	218,534			20,784			106,663			345,981
	Income (loss) before income taxes	$	164,822		$	8,124		$	(103,349	)	$	69,597
	Assets	$	1,361,577		$	9,534		$	116,022		$	1,487,133
		Years Ended December 31,
		2013			2012			2011
	Total Net Revenues
	United States	$	301,005		$	284,511		$	329,366
	Asia	57,557			51,486			27,960
	Europe, Middle East and North Africa	286,771			191,314			165,073
	Other	4,811			4,183			5,098
	Eliminations	(160,556		)	(114,179		)	(111,919		)
	Total	$	489,588		$	417,315		$	415,578
		Years Ended December 31,
		2013			2012			2011
	Operating and Other Expenses
	United States	$	290,549		$	264,706		$	299,841
	Asia	39,410			41,228			24,173
	Europe, Middle East and North Africa	265,218			173,467			130,254
	Other	3,107			3,214			3,632
	Eliminations	(160,556		)	(112,764		)	(111,919		)
	Total	$	437,728		$	369,851		$	345,981
		Years Ended December 31,
		2013			2012			2011
	Income Before Income Taxes
	United States	$	10,456		$	19,805		$	29,525
	Asia	18,147			10,258			3,787
	Europe, Middle East and North Africa	21,553			17,847			34,819
	Other	1,704			969			1,466
	Eliminations	—			(1,415		)	—
	Total	$	51,860		$	47,464		$	69,597

Litigation

Litigation	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Litigation	'
	Litigation
	In the ordinary course of business, we may from time to time be involved in litigation and claims incidental to the conduct of our business, including intellectual property claims. In addition, our business is also subject to extensive regulation, which may result in regulatory proceedings against us. We have been named in various arbitration and civil litigation cases brought by customers seeking damages for trading losses. Management has investigated these matters and believes that such cases are without merit and is defending them vigorously. However, the arbitrations and litigations are presently in various stages of the judicial process and no judgment can be made regarding the ultimate outcome of the arbitrators’ and/or court’s decisions.
	In October, 2011, the Trustee in bankruptcy, representing three debtors, Certified, Inc., Global Bullion Trading Group, Inc., and WJS Funding, Inc., filed an adversary complaint in the United States Bankruptcy Court for the Southern District of Florida against US, ODL Securities, Inc. and ODL Securities, Ltd. (the “Defendants”). Before the Defendants filed any response, the Trustee amended the Complaint to add ODL, FXCM Securities, LLC, FSL, FXCM, Inc., and Holdings as Defendants. The Amended Complaint asserts claims under the Federal Bankruptcy Code to recover allegedly preferential and fraudulent transfers to the Defendants, under the Racketeer Influenced and Corrupt Organizations Act (“RICO”), 18 U.S.C §1961 et seq., as well as the common law. The Amended Complaint seeks an unspecified amount of compensatory and punitive damages, interests, and costs. The Defendants have filed motions to dismiss the Amended Complaint in its entirety. Thereafter, the parties engaged in non-binding mediation. Ultimately a settlement was reached in the amount of $0.7 million which was approved by the Bankruptcy Court on June 20, 2012.
	In 2012, FXCMJ accrued $2.6 million as an estimate to settle certain trading system matters with the JFSA. The Company settled this matter for $2.3 million, which included an administrative penalty, during the first quarter of 2013.
	In January 2014, the equity Receiver for a former client of US, Revelation Forex Fund (“Revelation”), its principal, Kevin G. White (“White”), and related entities RFF GP, LLC (“RFF”), KGM Capital Management, LLC (“KGM”)(collectively “Fund”), filed suit against US, and certain unrelated defendants, in Texas state court.  The suit alleges that US is liable under the Texas Securities Act, and the common law: (i) as a “control person;” and, (ii) as an aider and abettor of fraud and a breach of fiduciary obligations; and, (iii) for its negligence.  The Receiver seeks joint and several liability for damages in excess of $3.8 million, plus exemplary damages under Texas law, interest, and attorneys’ fees.  On February 7, 2014, US filed the equivalent of a motion to dismiss and to compel arbitration based on the mandatory forum selection clause and arbitration agreement in its Client Agreement with the Fund. It also filed an Answer with multiple affirmative defenses. The motions are currently pending.
	In February 2014, UK and FSL entered into a settlement with the FCA following an investigation into trade execution practices of UK and FSL in the period from 2006 to 2010, as well as a breach of notification obligations to the FCA. UK and FSL agreed to pay (a) restitution to affected clients up to $9.9 million; and (b) a financial penalty of GBP 4.0 million, together with any unclaimed restitution.
	For the outstanding matters referenced above for which a loss is more than remote but less than likely, whether in excess of an accrued liability or where there is no accrued liability, we have estimated a range of possible loss. We believe the estimate of the aggregate range of possible loss in excess of accrued liabilities for such matters is between nil and $3.8 million as of December 31, 2013.
	In view of the inherent difficulty of predicting the outcome of litigation and claims, we cannot predict what the eventual outcome of the pending matters will be, what the timing of the ultimate resolution of these matters will be, or what the eventual loss related to each pending matter may be. Furthermore, the above-referenced matters represented in the estimated aggregate range of possible loss will change from time to time and actual results may vary significantly from the current estimate. An adverse outcome in one or more of these matters could be material to our results of operations or cash flows for any particular reporting period.

Subsequent_Events

Subsequent Events	12 Months Ended
	Dec. 31, 2013
Subsequent Events [Abstract]	'
Subsequent Events	'
	Subsequent Events
	The Company has evaluated subsequent events after the date of the consolidated financial statements to consider whether or not the impact of such events needed to be reflected or disclosed in the consolidated financial statements. Such evaluation was performed through the report date of the consolidated financial statements.
	On February 28, 2014, the Company, through a new entity, V3 Markets, LLC, created with the non-controlling members of Lucid, completed the acquisition of certain assets and liabilities of Infinium Capital  and certain of its affiliates.   Assets acquired included exchange memberships, trading network infrastructure and intellectual property. The acquisition is intended to expand the Company into a broader array of financial instruments and provide more robust connectivity to various financial exchanges. The consideration for the transaction was approximately $30.0 million consisting of cash, assumed liabilities and a credit of $11.9 million for the Infinium Capital senior secured notes held and exchanged by a consolidated subsidiary of the Company (see Note 10). The Company will hold a 50.1% interest in the new entity.
	As of March 14, 2014, the Company had an outstanding balance of $50 million under the Credit Agreement.
	The Company declared a quarterly dividend of $0.06 per share on its outstanding Class A common stock. The dividend is payable on April 1, 2014 to Class A stockholders of record at the close of business on March 21, 2014.

Significant_Accounting_Policie1

Significant Accounting Policies and Estimates (Policies)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Basis of Presentation	'
	Basis of Presentation
	The accompanying consolidated financial statements are presented in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The Company consolidates those entities in which it is the primary beneficiary of a variable-interest entity (VIE) as required by ASC 810, Consolidations (“ASC 810”), or entities where it has a controlling interest. Intercompany accounts and transactions are eliminated in consolidation.
	As indicated above, the Corporation operates and controls all of the businesses and affairs of Holdings and its subsidiaries. As such, the Corporation consolidates the financial results of Holdings and records a non-controlling interest for the economic interest in Holdings not owned by the Corporation. The Corporation’s and the non-controlling unit holders’ economic interest in Holdings was 54.8% and 45.2%, respectively, as of December 31, 2013. The Corporation’s and the non-controlling unit holders’ economic interest in Holdings was 42.5% and 57.5%, respectively, as of December 31, 2012.
	Net income attributable to the non-controlling interest in Holdings in the consolidated statements of operations represents the portion of earnings or loss attributable to the economic interest in Holdings held by the non-controlling unit holders. Net income attributable to other non-controlling interests in the consolidated statements of operations represents the portion of net income attributable to the non-controlling interests of Lucid, Faros and other consolidated subsidiaries or VIE's. Net income attributable to the non-controlling interest in Lucid represents the portion of earnings or loss attributable to the 49.9% economic interest held by Lucid non-controlling members whose allocation among the non-controlling members is not contingent upon services being provided. The portion of the 49.9% of Lucid earnings allocated among the non-controlling members of Lucid contingent on services provided is reported as a component of compensation expense under “Allocation of net income to Lucid members for services provided” in the consolidated statements of operations. Net income or loss attributable to the non-controlling interest in Faros (see Note 5) represents the portion of earnings or loss attributable to the 49.9% economic interest held by Faros non-controlling members. Net income or loss attributable to the non-controlling interests in other consolidated subsidiaries or VIE's represents the portion of earnings or loss attributable to the economic interests held by the non-controlling members.
	Non-controlling interests in the consolidated statements of financial condition represents the portion of equity attributable to the non-controlling interests of Holdings, Lucid, Faros and other consolidated subsidiaries or VIE's. The allocation of equity to the non-controlling interests is based on the percentage owned by the non-controlling interest in the respective entity.
	The Company's consolidated financial statements include the following significant subsidiaries of Holdings:
	Forex Capital Markets LLC	(“US”)
	FXCM Asia Limited	(“HK”)
	Forex Capital Markets Limited	(“UK”)
	FXCM Australia Limited	(“Australia”)
	ODL Group Limited	(“ODL”)
	FXCM Securities Limited	(“FSL”)
	FXCM Japan Securities Co., Ltd.	(“FXCMJ”)
	FXCM UK Merger Limited	(“Merger”)
	Lucid Markets Trading Limited	(“Lucid”)
	Lucid Markets LLP	("Lucid LLP")
	Faros Trading LLC	("Faros")
	Investments where the Company is deemed to exercise significant influence (generally defined as owning a voting interest of 20% to 50% ), but no control, are accounted for using the equity method of accounting. The Company records its pro-rata share of earnings or losses each period and records any dividends as a reduction in the investment balance. The carrying value of these investments are included in Other assets in the consolidated statements of financial condition and earnings or losses are included in Loss on equity method investments, net in the consolidated statements of operations.
	FXCMJ, a wholly owned subsidiary of Holdings, has a fiscal year end of March 31 while the Company has a fiscal year end of December 31. FXCMJ is a Japanese based foreign exchange provider and is required under Japanese law to have a fiscal year end of March 31. The difference between the Company's reporting year end and FXCMJ does not result in a material impact on the Company's financial position or results of operations.
	Certain reclassifications have been made to previously reported amounts to conform to the current presentation.
Use of Estimates	'
	Use of Estimates
	The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements as well as the reported amount of revenue and expenses during the year. Actual results could differ from those estimates and could have a material impact on the consolidated financial statements.
Cash and Cash Equivalents	'
	Cash and Cash Equivalents
	Cash and cash equivalents include cash at banks and highly liquid instruments with original maturities of less than 90 days at the time of purchase and cash collateral held by FX and CFD market makers related to hedging activities. At times, balances held in U.S. bank accounts may exceed federally insured limits. This potentially subjects the Company to concentration risk. The Company has not experienced losses in such accounts.
Cash and Cash Equivalents, held for customers	'
	Cash and Cash Equivalents, held for customers
	Cash and cash equivalents, held for customers represents cash held to fund customer liabilities. At times, balances held in U.S. bank accounts may exceed federally insured limits. This potentially subjects the Company to concentration risk. The Company has not experienced losses in such accounts.
	The balance arises primarily from cash deposited by customers and net realized gains from customer trading activity. The Company records a corresponding liability in connection with this amount that is included in customer account liabilities in the consolidated statements of financial condition (see Note 12). A portion of the balance is not available for general use due to regulatory restrictions in certain jurisdictions. These restricted balances were $1.0 billion as of December 31, 2013 and 2012.
Derivatives	'
	Due from/to Brokers
	Due from/to brokers represents the amount of the unsettled spot currency trades that the Company has open with its financial institutions. Also included in due from/to brokers is the fair value of derivative financial instruments discussed below. The Company has master netting agreements with its respective counterparties under which its due from/to brokers are presented on a net-by-counterparty basis in accordance with ASC 815 Derivatives and Hedging (“ASC 815”) and ASC Topic 210 Balance Sheet (“ASC 210”).
	Derivatives
	Derivative financial instruments are accounted for in accordance with ASC 815 and are included in Due from/to brokers in the consolidated statements of financial condition. The Company recognizes all derivative financial instruments in the consolidated statements of financial condition as either assets or liabilities at fair value. The Company enters into futures contracts to (i) economically hedge the open customer contracts on its CFD business and (ii) hedge trading in its electronic market making and institutional foreign exchange spot and futures markets. Futures contracts are exchanged traded contracts to either purchase or sell a specific asset at a specified future date for a specified price. Gains or losses on futures contracts related to the Company’s CFD business are included in Retail trading revenue and gains or losses on hedge trading in its electronic market making and institutional foreign exchange spot and futures markets are included in Institutional trading revenue in the consolidated statements of operations (see Note 22).
Fair Value Measurements	'
	Fair Value Measurements
	Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value measurement establishes a fair value hierarchy that prioritizes the inputs of valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. These three levels of fair value hierarchy are defined as follows:
	Level I:  Quoted prices in active markets for identical assets or liabilities, accessible by the Company at the measurement date.
	Level II:  Quoted prices for similar assets or liabilities in active markets, or quoted prices for identical or similar assets or liabilities in markets that are not active, or other observable inputs other than quoted prices.
	Level III:  Unobservable inputs for assets or liabilities.
	When Level I inputs are available, those inputs are selected for determination of fair value. To value derivatives that are characterized as Level II and III, the Company uses observable inputs for similar assets and liabilities that are available from pricing services or broker quotes. These observable inputs may be supplemented with other methods, including internal models that result in the most representative prices for assets and liabilities with similar characteristics. Multiple inputs may be used to measure fair value, however, the level of fair value for each derivative and financial asset or liability is based on the highest priority level of input within this fair value hierarchy.
Office, Communication and Computer Equipment, net	'
	Office, Communication and Computer Equipment, net
	Office, communication and computer equipment, net, consist of computer equipment, purchased technology hardware and software, internally developed software, leasehold improvements, furniture and fixtures and other equipment, licenses and communication equipment. Office, communication and computer equipment are recorded at historical cost, net of accumulated depreciation. Additions and improvements that extend the lives of assets are capitalized, while expenditures for repairs and maintenance are expensed as incurred. Certain costs of software developed or obtained for internal use are capitalized. Depreciation is computed using the straight-line method. The Company depreciates these assets using the following useful lives:
	Computer equipment	3 to 5 years
	Software	2 to 5 years
	Leasehold improvements	Lesser of the estimated economic useful life or the term of the lease
	Furniture and fixtures and other equipment	3 to 5 years
	Licenses	2 to 3 years
	Communication equipment	3 to 5 years
Valuation of Other Long-Lived Assets	'
	Valuation of Other Long-Lived Assets
	The Company also assesses potential impairments of its other long-lived assets, including office, communication and computer equipment, when there is evidence that events or changes in circumstances indicate that the carrying amount of an asset may not be recovered. An impairment loss is recognized when the carrying amount of the long-lived asset exceeds its fair value and is not recoverable. The carrying amount of a long-lived asset is not recoverable if it exceeds the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset. Any required impairment loss is measured as the amount by which the carrying amount of a long-lived asset exceeds its fair value and is recorded as a reduction in the carrying value of the related asset and a charge to operating results.
Business Combination	'
	Business Combinations
	The Company accounts for business acquisitions in accordance with ASC 805 and records assets acquired and liabilities assumed at their fair values as of the acquisition date. The Company records any excess purchase price over the value assigned to net tangible and identifiable intangible assets of a business acquired as goodwill. Acquisition related costs are expensed as incurred (see Note 5).
Goodwill	'
	Goodwill
	The Company recorded goodwill from various acquisitions. Goodwill represents the excess purchase price over the value assigned to the net tangible and identifiable intangible assets of a business acquired. Goodwill is allocated to the Company’s reporting units based on the assignment of the fair values of each reporting unit of the acquired company. For purposes of the goodwill impairment test, the Company has identified its Retail and Institutional trading segments as its reporting units. The Company performs a two-step goodwill impairment review at the reporting unit level annually, or in interim periods if certain events occur indicating that the carrying value may be impaired. The Company tests for impairment during the fourth quarter of our fiscal year using October 1 carrying values.
	The first step of the two-step process involves a comparison of the estimated fair value of a reporting unit to its carrying amount, including goodwill. In performing the first step, the Company determines the fair value of a reporting unit using a DCF analysis. Determining fair value requires the exercise of significant judgment, including judgments about appropriate discount rates, perpetual growth rates, the amount and timing of expected future cash flows. The cash flows employed in the DCF analyses are based on the Company’s most recent budgets and business plans and, when applicable, various growth rates are assumed for years beyond the current business plan period. Discount rate assumptions are based on an assessment of the risk inherent in the future cash flows of the respective reporting units. If the estimated fair value of a reporting unit exceeds its carrying amount, the goodwill of the reporting unit is not impaired and the second step of the impairment test is not necessary. If the carrying amount of a reporting unit exceeds its estimated fair value, then the second step of the goodwill impairment test must be performed. The second step of the goodwill impairment test compares the implied fair value of the reporting unit’s goodwill with its carrying amount to measure the amount of impairment loss, if any. The implied fair value of goodwill is determined in the same manner as the amount of goodwill recognized in a business combination (i.e., the estimated fair value of the reporting unit is allocated to all of the assets and liabilities of that reporting unit including any unrecognized intangible assets as if the reporting unit had been acquired in a business combination and the fair value of the reporting unit was the purchase price paid). If the carrying amount of the reporting unit’s goodwill exceeds the implied fair value of the reporting unit’s goodwill, an impairment loss is recognized in an amount equal to that excess.
	There was no impairment of goodwill for the year ended December 31, 2013. Although there is no impairment as of December 31, 2013, events such as economic weakness and unexpected significant declines in operating results of reporting units may result in our having to perform a goodwill impairment test for some or all of our reporting units prior to the required annual assessment. These types of events and the resulting analysis could result in goodwill impairment charges in the future (see Note 8)
Other Intangible Assets, net	'
	Other Intangible Assets, net
	Other intangible assets, net, primarily include customer relationships, proprietary technology, non-compete agreements and trade names recorded from various acquisitions.
	The customer relationships, non-compete agreements and trade names are finite-lived intangibles and are amortized on a straight-line basis over their estimated average useful life of 4 to 9 years, 3 to 9 years, and 3 years, respectively. Proprietary technology is also finite-lived intangibles and is amortized on a straight-line basis over their estimated average useful life of 4 to 7 years, respectively. The useful life of these intangibles is based on the period they are expected to contribute to future cash flows as determined by the Company's historical experience. For these finite-lived intangible assets subject to amortization, impairment is considered upon certain “triggering events” and is recognized if the carrying amount is not recoverable and the carrying amount exceeds the fair value of the intangible asset. There was no impairment of finite-lived intangible assets for the years ended December 31, 2013, 2012 and 2011.
	The FX trading license is an indefinite-lived asset that is not amortized but tested for impairment. The Company’s policy is to test for impairment at least annually or in interim periods if certain events occur indicating that the fair value of the asset may be less than its carrying amount. An impairment test on this indefinite-lived asset is performed during the fourth quarter of the Company’s fiscal year using the October 1 carrying value. Impairment exists if the carrying value of the indefinite-lived intangible asset exceeds its fair value. There was no impairment of indefinite-lived intangible assets for the years ended December 31, 2013, 2012 and 2011
Equity Method Investment	'
	Equity Method Investments
	Investments where the Company is deemed to exercise significant influence (generally defined as owning a voting interest of 20% to 50%), but no control, are accounted for using the equity method of accounting. The Company records its pro-rata share of earnings or losses each period and records any dividends as a reduction in the investment balance. Additionally, the carrying value of investments accounted for using the equity method of accounting is adjusted downward to reflect any impairment in value. For investments accounted for using the cost or equity method of accounting, the Company evaluates information (e.g., budgets, business plans, financial statements, etc.) in addition to quoted market prices, if any, in determining whether an other-than-temporary decline in value exists. Factors indicative of an impairment in value include recurring operating losses, credit defaults and subsequent rounds of financing at an amount below the cost basis of the Company’s investment.
	All of the Company’s equity method investments are accounted for at cost. These investments are included in Other assets in the consolidated statements of financial condition and earnings or losses are included in Loss on equity method investments, net in the consolidated statements of operations. Equity method investments are included in institutional and corporate for purposes of segment reporting.
Accounts Receivable, net	'
	Accounts Receivable, net
	As of December 31, 2013 and 2012, accounts receivable, net, consisted primarily of amounts due from institutional customers relating to the Company's FX business, and fees receivable from the Company's white label service to third parties and payments for order flow, described in “Retail Trading Revenue” below. Receivables are shown net of reserves for uncollectible accounts. The reserve for bad debts is maintained at a level that management believes to be sufficient to absorb estimated losses in the accounts receivable portfolio. The reserve is increased by the provision for bad debts which is charged against operating results and decreased by the amount of charge-offs, net of recoveries. The amount charged against operating results is based on several factors including, but not limited to, a continuous assessment of the collectability of each account, the length of time a receivable is past due and our historical experience with the particular customer. As of December 31, 2013 and 2012, the reserve netted against receivables in the consolidated statements of financial condition was not material.
Notes Receivable	'
	Notes Receivable
	Notes receivable represent receivable for notes acquired for cash plus accrued interest. Notes receivable are initially recorded at the amount of cash exchanged plus accrued interest. Interest income on the notes is recorded on an accrual basis and included in Interest income in the consolidated statements of operations. The Company individually assesses its notes receivables for impairment using internally generated cash flow projections to determine if the notes will be repaid under the expected terms of the note agreements. If the Company concludes that the counterparty will not repay a note in accordance with its terms, the Company considers the note impaired and begins recognizing interest income on a cash basis, if any. To measure impairment, the Company calculates the estimated fair value of the collateral. If the estimated fair value of the collateral is less than the carrying value of the note receivable, the Company establishes an impairment reserve for the difference. If it is likely that a note will not be collected based on financial or other business indicators, the Company’s policy is to charge off the note in the period which it deems it uncollectible
Other Assets	'
	Other Assets
	Other assets include prepaid expenses, equity method investments, deposits for rent security and deferred debt costs (see Note 11).
Accounts Payable and Accrued Expenses	'
	Accounts Payable and Accrued Expenses
	Accounts payable and accrued expenses include operating expenses payable, amounts due to the Lucid non-controlling members in connection with trade settlements, commissions payable which represents balances owed to referring brokers for trades transacted by customers that were introduced to the Company by such brokers, bonuses payable, income taxes payable, a payable for a portion of the cash consideration relating to the business acquisitions (see Notes 5 and 13) and interest due on borrowings.
Foreign Currency	'
	Foreign Currency
	Foreign denominated assets and liabilities are re-measured into the functional currency at exchange rates in effect at the statements of financial condition dates through the consolidated statements of operations. Gains or losses resulting from foreign currency transactions are re-measured using the rates on the dates on which those elements are recognized during the period, and are included in Retail and Institutional trading revenue in the consolidated statements of operations. The Company recorded gains of $5.3 million, $0.8 million and $3.1 million for the years ended December 31, 2013, 2012 and 2011, respectively.
	Translation gains or losses resulting from translating the Company’s subsidiaries’ financial statements from the functional currency to the reporting currency, net of tax, are included in Foreign currency translation gain (loss) in the consolidated statements of comprehensive income. Assets and liabilities are translated at the statement of financial condition date while revenues and expenses are translated at an applicable average rate.
	Parent's Accounting for the Cumulative Translation Adjustment upon Derecognition of an Investment within a Foreign Entity or of an Investment in a Foreign Entity
	In March 2013, the FASB issued ASU No. 2013-05, Parent's Accounting for the Cumulative Translation Adjustment upon Derecognition of Certain Subsidiaries or Groups of Assets within a Foreign Entity or of an Investment in Foreign Entity. This standard addresses whether consolidation guidance or foreign currency guidance applies to the release of the cumulative translation adjustment into net income when a parent sells all or a part of its investment in a foreign entity or no longer holds a controlling financial interest in a subsidiary or net assets that are a business (other than a sale of in-substance real estate) within a foreign entity. The standard also resolves the diversity in practice for the cumulative translation adjustment treatment in business combinations achieved in stages involving foreign entities.
	Under this standard, the entire amount of the cumulative translation adjustment associated with the foreign entity should be released into earnings when there has been: (i) a sale of a subsidiary or group of net assets within a foreign entity and the sale represents a complete or substantially complete liquidation of the foreign entity in which the subsidiary or the net assets had resided; (ii) a loss of a controlling financial interest in an investment in a foreign entity; or (iii) a change in accounting method from applying the equity method to an investment in a foreign entity to consolidating the foreign entity.
	ASU No. 2013-05 is effective for fiscal years and interim periods beginning after December 15, 2013, and will be applied prospectively. The Company plans to adopt the standard on its required effective date of January 1, 2014 and does not expect the adoption of the standard to have a material effect on our consolidated financial condition, results of operations or cash flows.
Revenue Recognition	'
	Revenue Recognition
	The Company makes foreign currency markets for customers trading in FX spot markets and through its subsidiary FSL, engages in equity and related brokerage activities. FX transactions are recorded on the trade date and positions are marked to market daily with related gains and losses, including gains and losses on open spot transactions, recognized currently in income. Commissions earned on brokerage activities are recorded on a trade date basis and are recognized currently in income.
Retail Trading Revenue	'
	Retail Trading Revenue
	Under the Company’s retail agency FX offering, trading revenue is earned by adding a markup to the price provided by FX market makers generating trading revenue based on the volume of transactions and is recorded on trade date. Under the agency model, when a customer executes a trade on the best price quotation presented by the FX market maker, the Company acts as a credit intermediary, or a riskless principal, simultaneously entering into a trade with the customer and the FX market maker. This agency model has the effect of automatically hedging the Company's positions and eliminating market risk exposure. Retail trading revenues principally represent the difference of the Company's realized and unrealized foreign currency trading gains or losses on its positions with customers and the systematic hedge gains and losses from the trades entered into with the FX market makers. Retail trading revenue also includes fees earned from arrangements with other financial institutions to provide platform, back office and other trade execution services. This service is generally referred to as a white label arrangement. The Company earns a percentage of the markup charged by the financial institutions to their customers. Fees from this service are recorded when earned on a trade date basis. Additionally, the Company earns income from trading in CFDs, rollovers, payments for order flow, and spread betting. Income or loss on CFDs represents the difference between the Company's realized and unrealized trading gains or losses on its positions and the hedge gains or losses with the other financial institutions. Income or loss on CFDs is recorded on a trade date basis. Income or loss on rollovers is the interest differential customers earn or pay on overnight currency pair positions held and the markup that the Company receives on interest paid or received on currency pair positions held overnight. Income or loss on rollovers is recorded on a trade date basis. Income earned on order flow represents payments received from certain FX market makers in exchange for routing trade orders to these firms for execution. The Company's order routing software ensures that payments for order flow do not affect the routing of orders in a manner that is detrimental to its retail customers. The Company recognizes payments for order flow as earned on a trade date basis. Spread betting is where a customer takes a position against the value of an underlying financial instrument moving either upward or downward in the market. Income on spread betting is recorded as earned on a trade date basis.
Institutional Trading Revenue	'
	Institutional Trading Revenue
	Institutional trading revenue relates to commission income generated by facilitating spot FX trades on behalf of institutional customers through the services provided by FXCM Pro and Faros (see Note 5). The counterparties to these trades are external financial institutions that also hold customer account balances. The Company receives commission income on these trades without taking any market or credit risk. Institutional trading revenue is recorded on a trade date basis. The Company also earns income from market making and electronic trading in the institutional foreign exchange spot and futures markets through Lucid. Income on market making and electronic trading in foreign exchange spot and future currencies represents the spread between the bid and ask price for positions purchased and sold and the change in value of positions purchased and sold. Income on market making is recorded as trading gains, net of trading losses, on a trade date basis.
Interest Income	'
	Interest Income
	Interest income consists of interest earned on cash and cash equivalents and cash and cash equivalents, held for customers and is recognized in the period earned.
Other Income	'
	Other Income
	Other income primarily includes amounts earned from the sale of market data, equity and equity option brokerage activities, account maintenance fees, ancillary fee income and recovery of accounts receivable previously written off.
	For the year ended December 31, 2013, Other income in the consolidated statements of operations includes $7.0 million of revenue related to the re-measurement of the contingent consideration recorded for the acquisition of Faros (see Note 5), partly offset by a charge of $1.2 million attributable to the re-measurement of the Due to related parties pursuant to tax receivable agreement to reflect a revised U.S. federal tax rate. For the year ended December 31, 2012, Other income in the consolidated statements of operations includes a $1.4 million gain related to a settlement with the former owners of ODL.
	For the year ended December 31, 2011, Other income in the consolidated statements of operations includes $4.5 million of revenue related to the termination of a trade execution services contract that resulted in the recognition of previously deferred income and $3.3 million attributable to the re-measurement of the Due to related parties pursuant to tax receivable agreement to reflect the Company’s revised U.S. Federal income tax rate.
Communications and Technology	'
	Communications and Technology
	Communications and technology expense consists primarily of costs for network connections to our electronic trading platforms, telecommunications costs, and fees paid for access to external market data. This expense is affected primarily by the growth of electronic trading, our network/ platform capacity requirements and by changes in the number of telecommunication hubs and connections which provide our customers with direct access to our electronic trading platforms.
Trading Costs, Prime Brokerage and Clearing Fees	'
	Trading Costs, Prime Brokerage and Clearing Fees
	Trading costs, prime brokerage and clearing fees primarily represent fees paid to third party clearing banks and prime brokers for clearing foreign exchange spot futures currency and contract transactions, transaction fees paid to exchanges, equity options brokerage activity fees, and fees paid to third party providers for use of their platform for the Company’s market making trading business. Clearing fees primarily fluctuate based on changes in volume, rate of clearing fees charged by clearing banks and rate of fees paid to exchanges.
Referring Broker Fees	'
	Referring Broker Fees
	Referring broker fees represent commissions paid to brokers for introducing trading customers to the Company. Commissions are determined based on the number and size of transactions executed by the customers and are recorded on a trade date basis.
Compensation and Benefits	'
	Compensation and Benefits
	Compensation and benefits expense represents employee and member salaries and benefit expense, including stock based compensation expense.
	The Company accounts for stock-based compensation in accordance with ASC 718, Compensation-Stock Compensation (“ASC 718”). The fair value of the Company’s stock-based compensation is estimated using the Black-Scholes option pricing model or the fair value of the Corporation’s Class A common stock. The Company recognizes compensation expense for equity awards on a straight-line basis over the requisite service period of the award. Compensation expense is adjusted for an estimate of equity awards that do not vest in the future because service or performance conditions are not satisfied (forfeitures) and have been included in Compensation and benefits in the consolidated statements of operations (see Note 16.
Advertising and Marketing	'
	Advertising and Marketing
	Advertising and marketing costs are charged to operations when incurred.
General and Administrative Expenses	'
	General and Administrative Expenses
	General and administrative expenses include bank processing and regulatory fees, professional and consulting fees, occupancy and equipment expense and other administrative costs. Bank processing fees are costs associated with the processing of credit card transactions. Regulatory fees are volume-based costs and annual fees charged by certain regulatory authorities. General and administrative expense for the year ended December 31, 2013 includes a charge of $16.6 million related to a liability established pertaining to a settlement with the FCA regarding our pre August 2010 trade execution practices (see Note 27).
Income Taxes	'
	Presentation of Unrecognized Tax Benefits
	In July 2013, the FASB issued ASU No. 2013-11, Presentation of Unrecognized Tax Benefits When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. This standard requires a liability related to unrecognized tax benefits to be presented as a reduction to the related deferred tax asset for a net operating loss carryforward or a tax credit carryforward. When the carryforwards are not available at the reporting date under the tax law of the applicable jurisdiction or the tax law of the applicable jurisdiction does not require, and the entity does not intend to use, the deferred tax asset for such purpose, the unrecognized tax benefit will be presented in the financial statements as a liability and will not be combined with the related deferred tax asset.
	ASU No. 2013-11 is effective for fiscal years and interim periods beginning after December 15, 2013, but earlier adoption is permitted. Upon adoption, the standard should be applied prospectively to unrecognized tax benefits that existed at the effective date. Retrospective application is permitted. The Company plans to adopt the standard prospectively on its required effective date of January 1, 2014 and does not expect the adoption of the standard to have a material effect on its consolidated financial condition, results of operations or cash flows.
	Income Taxes
	Holdings operates in the United States (“U.S.”) as a limited liability company that is treated as a partnership for U.S. Federal, state and local income tax purposes. As a result, Holdings' income from its U.S. operations is not subject to U.S. federal income tax because the income is attributable to its members. Accordingly, the Company’s U.S. tax provision is solely based on the portion of Holdings’ income attributable to the Corporation and excludes the income attributable to other members of Holdings whose income is included in Net Income attributable to non-controlling interest in FXCM Holdings, LLC in the consolidated statements of operations.
	Income taxes are accounted for in accordance with ASC 740, Income Taxes ("ASC 740"), which requires that deferred tax assets and liabilities are recognized, using enacted tax rates, for the effect of temporary differences between the book and tax basis of recorded assets and liabilities. Deferred tax assets, including net operating losses and income tax credits, are reduced by a valuation allowance if it is "more likely than not" that some portion or all of the deferred tax assets will not be realized (see Note 24).
	In addition to U.S. federal and state income taxes, Holdings is subject to Unincorporated Business Tax which is attributable to Holdings' operations apportioned to New York City. The Company’s foreign subsidiaries are also subject to local taxes.
	In accordance with ASC 740, we evaluate a tax position to determine whether it is more likely than not that the tax position will be sustained upon examination, based on the technical merits of the position. If the position does not meet a more likely than not threshold, a tax reserve is established and no income tax benefit is recognized. We are audited by U.S. federal and state, as well as foreign, tax authorities. In some cases, many years may elapse before a tax return containing tax positions for which an ASC 740 reserve has been established is examined and an audit is completed. As audit settlements are reached, we adjust the corresponding reserves, if required, in the period in which the final determination is made. While it is difficult to predict the final outcome or timing of a particular tax matter, we believe that our reserves for uncertain tax positions are recorded pursuant to the provisions of ASC 740.
Fair Value Measurements and Related Disclosures	'
	Fair Value Measurements and Related Disclosures
	In May 2011, the FASB issued authoritative guidance that provides a uniform framework for fair value measurements and related disclosures between U.S GAAP and International Financial Reporting Standards. Additional disclosure requirements under this guidance include: (1) for Level III fair value measurements, quantitative information about unobservable inputs used, a description of the valuation processes used by the entity, and a qualitative discussion about the sensitivity of the measurements to changes in the unobservable inputs; (2) for an entity's use of nonfinancial asset that is different from the asset's highest and best use, the reason for the difference; (3) for financial instruments not measured at fair value but for which disclosure of fair value is required, the fair value hierarchy level in which the fair value measurements were determined; and (4)the disclosure of all transfers between Level I and Level II of the fair value hierarchy. This guidance became effective for the Company on January 1, 2012 and did not have a material impact on its consolidated financial statements.
Presentation of Comprehensive Income	'
	Presentation of Comprehensive Income
	In June 2011, the FASB issued authoritative guidance that eliminates the option to present components of other comprehensive income as part of the statement of changes in stockholders' equity, among other updates to the presentation of comprehensive income. Under this guidance, an entity has the option to present the total of comprehensive income, the components of net income and the components of other comprehensive income either in a single continuous statement of comprehensive income or in two separate but consecutive statements. In addition, an entity is required to present on the face of the financial statements reclassification adjustments for items that are reclassified from other comprehensive income to net income in the statement(s) where the components of net income and the components of other comprehensive income are presented. This guidance became effective for the Company on January 1, 2012 and did not have a material impact on its consolidated financial statements.
Balance Sheet Offsetting	'
	Balance Sheet Offsetting
	In December 2011, the FASB issued Accounting Standards Update (“ASU”) No. 2011-11 which requires disclosures of both gross and net information about instrument and transactions eligible for offset as well as transactions subject to an agreement similar to a master netting agreement. In February 2013, the FASB issued ASU No. 2013-01 which limited the scope of the offsetting disclosures to recognized derivative instruments accounted for in accordance with ASC 815. ASU No. 2013-01 is effective for annual periods beginning on or after January 1, 2013 and interim periods within those annual periods and must be applied retrospectively. This guidance became effective for the Company on January 1, 2013 and did not have a material impact the presentation of the Company’s unaudited condensed consolidated financial statements.
Testing Goodwill for Impairment	'
	Testing Goodwill for Impairment
	In July 2012, the FASB issued amended guidance relating to FASB ASC Topic 350, Intangibles —  Goodwill and Other, which permits an entity to first assess qualitative factors to determine whether it is more likely than not that an indefinite-lived intangible asset is impaired as a basis for determining whether it is necessary to perform the quantitative impairment test in accordance with ASC Topic 350. The more-likely-than-not threshold is defined as having a likelihood of more than 50 percent. If, after assessing the totality of events and circumstances, an entity concludes that it is not more likely than not that the indefinite-lived intangible asset is impaired, then no further action is required. This guidance became effective for the Company on January 1, 2013. Since this guidance only changes the manner in which the Company assesses indefinite-lived intangible assets for impairment, adoption of this guidance did not have a material effect on the Company’s financial position or results of operations.
Reclassifications Out of Accumulated Other Comprehensive Income	'
	Reclassification Out of Accumulated Other Comprehensive Income
	In February 2013, the FASB issued ASU No. 2013-02, Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income. This guidance requires an entity to present information about significant items reclassified out of Accumulated Other Comprehensive Income (AOCI) by component and for items reclassified out of AOCI and into net income, an entity must disclose the effect of such items on the affected net income line item. ASU No. 2013-02 is effective for annual periods beginning on or after January 1, 2013 and interim periods within those annual periods and must be applied retrospectively. This guidance became effective for the Company on January 1, 2013 and did not have a material impact the presentation of the Company’s unaudited condensed consolidated financial statements.
Certain Obligations Resulting from Joint and Several Liability Arrangements	'
	Certain Obligations Resulting from Joint and Several Liability Arrangements
	In February 2013, the FASB issued ASU No. 2013-20, Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation is Fixed at the Reporting Date. This standard requires an entity to measure obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date as the sum of (i) the amount the entity agreed to pay on the basis of its arrangement among its co-obligors and (ii) any additional amount it expect to pay on behalf of its co-obligors.
	ASU No. 2013-20 is effective for fiscal years and interim periods beginning after December 15, 2013, but earlier adoption is permitted. Upon adoption, the standard should be applied retrospectively to all prior periods presented. The Company plans to adopt the standard on its required effective date of January 1, 2014 and does not expect the adoption of this standard to have a material effect on our consolidated financial condition, results of operations or cash flows.

Significant_Accounting_Policie2

Significant Accounting Policies and Estimates (Tables)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Property, Plant and Equipment	'
	Computer equipment		3 to 5 years
	Software		2 to 5 years
	Leasehold improvements		Lesser of the estimated economic useful life or the term of the lease
	Furniture and fixtures and other equipment		3 to 5 years
	Licenses		2 to 3 years
	Communication equipment		3 to 5 years
	Office, communication and computer equipment, net, including capitalized software development costs, leasehold improvements, capital leases, furniture and fixtures and other equipment, licenses and communication equipment, consisted of the following as of December 31, 2013 and 2012, with amounts in thousands:
		December 31, 2013			December 31, 2012
	Computer equipment	$	28,047		$	34,541
	Software	47,138			31,476
	Leasehold improvements	9,687			9,478
	Furniture and fixtures and other equipment	3,427			3,185
	Licenses	10,101			20,222
	Communication equipment	1,664			1,522
		100,064			100,424
	Less: Accumulated depreciation	(50,899		)	(50,108		)
	Office, communication and computer equipment, net	$	49,165		$	50,316

NonControlling_Interest_Tables

Non-Controlling Interest (Tables)	12 Months Ended
	Dec. 31, 2013
Noncontrolling Interest [Abstract]	'
Corporation's interests in Holdings	'
	Changes in the non-controlling and the Corporation’s interests in Holdings for the year ended December 31, 2013 are presented in the following table:
		Controlling Units		Non-		Total Units		FXCM		Non-		Total
				Controlling Units				Inc.		Controlling
	Balance as of January 1, 2013	34,683,599		46,930,192		81,613,791		42.5	%	57.5	%	100	%
	Holding Units repurchased related to Class A common stock repurchased	(1,815,800	)	—		(1,815,800	)	(0.8	)%	0.8	%	—	%
	Holding Units acquired by FXCM Inc. related to exchanges of Holding Units for shares of Class A common stock	10,094,371		(10,094,371	)	—		12.3	%	(12.3	)%	—	%
	Exercise of stock options	1,702,714		—		1,702,714		0.8	%	(0.8	)%	—	%
	Balance as of December 31, 2013	44,664,884		36,835,821		81,500,705		54.8	%	45.2	%	100	%

Business_Acquisition_Tables

Business Acquisition (Tables)	12 Months Ended
	Dec. 31, 2013
Business Acquisition [Line Items]	'
Business Acquisition, Pro Forma Information	'
	Pro forma condensed combined financial information for the acquisitions completed in 2013 (i.e., Faros), 2012 (i.e., Lucid) and 2011 (i.e., Foreland and FXCMJ) are presented as they may have appeared if all acquisitions had been completed on January 1, 2013, 2012 and 2011, with amounts in thousands:
		For the Years Ended
		December 31, 2013			December 31, 2012		December 31, 2011
	Total revenues	$	491,217		$	463,767	$	588,028
	Net income before non-controlling interest	$	32,463		$	49,224	$	115,884
Faros Trading LLC	'
Business Acquisition [Line Items]	'
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	'
	The following condensed statement of net assets acquired reflects the amounts of Faros net assets recognized as of the Faros Acquisition Date, with amounts in thousands:
	Condensed Statement of Net Assets Acquired
		As of September 20, 2013
	Assets
	Cash and cash equivalents	$	1,055
	Accounts receivable, net	40
	Office, communication and computer equipment, net	31
	Intangible assets	8,030
	Other assets	76
	Total assets	$	9,232
	Liabilities
	Accounts payable and accrued expenses	1,065
	Total liabilities	1,065
	Fair value of net assets acquired	$	8,167
	Faros Purchase Price Allocation
	(Amounts in thousands)
	Purchase price				$	15,631
	Non-controlling interest				15,569
	Total fair value at Acquisition Date				31,200
	Net assets acquired	$	137
	Adjustments to reflect acquired assets and liabilities at fair value
	Customer relationships (1)	6,000
	Non-compete agreement (2)	1,900
	Trade name (3)	130
	Fair value of net assets acquired				8,167
	Goodwill resulting from the Faros acquisition				$	23,033
	(1)	Consists of institutional and bank customers, with an amortization life of 4 years.
	(2)	Amortization life is 9 years.
	(3)	Amortization life is 3 years.
Business Combination, Separately Recognized Transactions	'
	The following condensed financial information presents the resulting operations of Faros from the Faros Acquisition Date to December 31, 2013, with amounts in thousands:
		For the period September 20, 2013 to December 31, 2013
	Total revenue	$	526
	Net loss	$	(301	)
Lucid Markets Trading Limited	'
Business Acquisition [Line Items]	'
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	'
	The following condensed statement of net assets acquired reflects the amounts of Lucid net assets recognized as of the Acquisition Date, with amounts in thousands:
		As of June 18, 2012
	Assets
	Cash and cash equivalents	$	28,656
	Accounts receivable, net	5,100
	Due from brokers	302
	Deferred tax asset	11,311
	Office, communication and computer equipment, net	499
	Intangible assets	84,900
	Other assets	226
	Total assets	$	130,994
	Liabilities
	Accounts payable and accrued expenses	13,362
	Total liabilities	13,362
	Fair value of net assets acquired	$	117,632
	Lucid Purchase Price Allocation (¹)
	(Amounts in thousands)
	Purchase price				$	192,784
	Non-Controlling interest				160,165
	Total fair value at Acquisition Date				352,949
	Net assets acquired	$	32,732
	Adjustments to reflect acquired assets and liabilities at fair value
	Proprietary technology (2)	83,900
	Non-compete agreements (3)	1,000
	Fair value of net assets acquired				117,632
	Goodwill resulting from the Lucid acquisition				$	235,317
	__________________
	(¹) The amounts included in the Lucid Purchase Price Allocation table represent the allocation of the purchase price and includes revisions made during the 12 months remeasurement period from the Acquisition Date.
	(²) Consists of internally developed software platforms through which the Company: (i) executes its specific trading strategies, with an amortization life of 4 years and (ii) clears and efficiently settle trades, with an amortization life of 7 years.
	(³) Consists of two non-compete agreements with amortization lives of 3 years.
Business Combination, Separately Recognized Transactions	'
	The following condensed financial information presents the resulting operations of Lucid from the Acquisition Date to December 31, 2012:
		For the period June 18, 2012 to December 31, 2012
	Total revenue	$	42,198
	Net income	$	21,446
Foreland	'
Business Acquisition [Line Items]	'
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	'
	Foreland Purchase Price Allocation
	(Amounts in thousands)
	Purchase price				$	37,654
	Net assets acquired	$	21,460
	Adjustments to reflect acquired assets and liabilities at fair value
	Customer relationships(1)	9,925
	Deferred tax liability	(3,726		)
	Fair value of net assets acquired				27,659
	Goodwill resulting from the Foreland acquisition				$	9,995
	_______________
	(1)	Consists of retail customers. The amortization life is 6 years.
	The following condensed statement of net assets acquired reflects the amounts of Foreland net assets recognized as of October 7, 2011, with amounts in thousands:
		As of October 7, 2011
	Assets
	Cash and cash equivalents	$	29,853
	Cash and cash equivalents, held for customers	172,826
	Accounts receivable, net	501
	Office, communication and computer equipment, net	847
	Intangible assets	9,934
	Other assets	1,199
	Total assets	$	215,160
	Liabilities
	Customer account liabilities	$	172,826
	Accounts payable and accrued expenses	6,502
	Due to brokers	4,447
	Deferred tax liability	3,726
	Total liabilities	187,501
	Fair value of net assets acquired	$	27,659
Fxcm Japan	'
Business Acquisition [Line Items]	'
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	'
	The following condensed statement of net assets acquired reflects the amounts of FXCMJ net assets recognized as of March 31, 2011, with amounts in thousands:
		As of March 31, 2011
	Assets
	Cash and cash equivalents	$	9,827
	Cash and cash equivalents, held for customers	114,024
	Due from broker	3,885
	Accounts receivable, net	194
	Tax receivable	478
	Office, communication and computer equipment, net	2,279
	Intangible assets	1,064
	Other assets	1,189
	Total assets	$	132,940
	Liabilities
	Customer account liabilities	$	114,023
	Accounts payable and accrued expenses	3,561
	Deferred tax liability	397
	Total liabilities	117,981
	Fair value of net assets acquired	$	14,959
	FXCM Japan Inc. Purchase Price Allocation
	(Amounts in thousands)
	Purchase price				$	15,725
	Net assets acquired	$	14,301
	Adjustments to reflect acquired assets and liabilities at fair value
	Customer relationships (1)	1,055
	Deferred tax liability	(397		)
	Fair value of net assets acquired				14,959
	Goodwill resulting from the FXCMJ acquisition				$	766
	_______________
	(1)	Consists of retail customers. The amortization life is 6 years.

Office_Communication_and_Compu1

Office, Communication and Computer Equipment, net (Tables)	12 Months Ended
	Dec. 31, 2013
Property, Plant and Equipment [Abstract]	'
Property, Plant and Equipment	'
	Computer equipment		3 to 5 years
	Software		2 to 5 years
	Leasehold improvements		Lesser of the estimated economic useful life or the term of the lease
	Furniture and fixtures and other equipment		3 to 5 years
	Licenses		2 to 3 years
	Communication equipment		3 to 5 years
	Office, communication and computer equipment, net, including capitalized software development costs, leasehold improvements, capital leases, furniture and fixtures and other equipment, licenses and communication equipment, consisted of the following as of December 31, 2013 and 2012, with amounts in thousands:
		December 31, 2013			December 31, 2012
	Computer equipment	$	28,047		$	34,541
	Software	47,138			31,476
	Leasehold improvements	9,687			9,478
	Furniture and fixtures and other equipment	3,427			3,185
	Licenses	10,101			20,222
	Communication equipment	1,664			1,522
		100,064			100,424
	Less: Accumulated depreciation	(50,899		)	(50,108		)
	Office, communication and computer equipment, net	$	49,165		$	50,316

Goodwill_Tables

Goodwill (Tables)	12 Months Ended
	Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Changes in Goodwill by Segment	'
	The following table presents the changes in goodwill by segment during the year ended December 31, 2013, with amounts in thousands:
		Retail Trading			Institutional Trading			Total
	Balance at January 1, 2013	$	37,851		$	247,803		$	285,654
	Goodwill acquired	—			23,033			23,033
	Goodwill adjustment/remeasurement	1,387			(1,196		)	191
	Foreign currency translation adjustment	(1,159		)	217			(942		)
	Balance at December 31, 2013	$	38,079		$	269,857		$	307,936

Other_Intangible_Assets_net_Ta

Other Intangible Assets, net (Tables)	12 Months Ended
	Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Schedule of Acquired Finite-Lived Intangible Assets by Major Class	'
	The Company’s acquired intangible assets consisted of the following as of December 31, 2013 and 2012, with amounts in thousands:
		December 31, 2013									December 31, 2012
		Gross Carrying Amount			Accumulated Amortization			Net Carrying Amount			Gross Carrying Amount			Accumulated Amortization			Net Carrying Amount
	Finite-lived intangible assets
	Customer relationships	$	37,746		$	(14,529	)	$	23,217		$	32,269		$	(9,815	)	$	22,454
	Non-compete agreements	10,507			(8,177		)	2,330			8,214			(5,841		)	2,373
	Proprietary technology	83,900			(31,849		)	52,051			83,900			(11,081		)	72,819
	Trade name	177			(13		)	164			—			—			—
	Foreign currency translation adjustment	(1,831		)	172			(1,659		)	(220		)	(244		)	(464		)
	Total finite-lived intangible assets	$	130,499		$	(54,396	)	$	76,103		$	124,163		$	(26,981	)	$	97,182
	Indefinite-lived intangible assets
	License	610			—			610			610			—			610
	Total indefinite-lived intangible assets	$	610		$	—		$	610		$	610		$	—		$	610
Acquired Intangible Assets	'
	The Company’s acquired intangible assets consisted of the following as of December 31, 2013 and 2012, with amounts in thousands:
		December 31, 2013									December 31, 2012
		Gross Carrying Amount			Accumulated Amortization			Net Carrying Amount			Gross Carrying Amount			Accumulated Amortization			Net Carrying Amount
	Finite-lived intangible assets
	Customer relationships	$	37,746		$	(14,529	)	$	23,217		$	32,269		$	(9,815	)	$	22,454
	Non-compete agreements	10,507			(8,177		)	2,330			8,214			(5,841		)	2,373
	Proprietary technology	83,900			(31,849		)	52,051			83,900			(11,081		)	72,819
	Trade name	177			(13		)	164			—			—			—
	Foreign currency translation adjustment	(1,831		)	172			(1,659		)	(220		)	(244		)	(464		)
	Total finite-lived intangible assets	$	130,499		$	(54,396	)	$	76,103		$	124,163		$	(26,981	)	$	97,182
	Indefinite-lived intangible assets
	License	610			—			610			610			—			610
	Total indefinite-lived intangible assets	$	610		$	—		$	610		$	610		$	—		$	610
Estimated Future Amortization Expense for Acquired Intangible Assets Outstanding	'
	Estimated future amortization expense for acquired intangible assets outstanding as of December 31, 2013 is as follows, with amounts in thousands:
	Year Ending December 31,	Estimated Amortization Expense
	2014	$	27,655
	2015	27,431
	2016	15,562
	2017	3,068
	2018	1,022
	Thereafter	1,365
		$	76,103

Other_Assets_Tables

Other Assets (Tables)	12 Months Ended
	Dec. 31, 2013
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]	'
Components of Other Assets	'
	Other assets were comprised of the following as of December 31, 2013 and 2012, with amounts in thousands:
		31-Dec-13		31-Dec-12
	Prepaid expenses	$	5,738	$	5,439
	Equity method investments	9,793		12,000
	Deferred debt issuance costs	7,131		1,109
	Deposits	1,492		1,555
	Other	162		13
		$	24,316	$	20,116

Accounts_Payable_and_Accrued_E1

Accounts Payable and Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2013
Payables and Accruals [Abstract]	'
Accounts Payable and Accrued Expenses	'
	Accounts payable and accrued expenses were comprised of the following as of December 31, 2013 and 2012, with amounts in thousands:
		December 31, 2013		December 31, 2012
	Operating expenses payable	$	41,528	$	28,793
	Due to Lucid non-controlling members	9,995		9,611
	Commissions payable	9,485		8,126
	Bonus payable	7,455		3,945
	Income tax payable	1,046		1,231
	Acquisition cash consideration payable	—		808
	Interest due on borrowings	177		121
	Other	11		—
		$	69,697	$	52,635

Earnings_per_Share_Tables

Earnings per Share (Tables)	12 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Reconciliation of Numerator and Denominator Used in Basic and Diluted EPS Calculations	'
	The following is a reconciliation of the numerator and denominator used in the basic and diluted EPS calculations, with amounts in thousands except per share data:
		Year Ended December 31, 2013		Year Ended December 31, 2012		Year Ended December 31, 2011
	Basic and diluted net income per share:
	Numerator
	Net income available to holders of Class A common stock	$	14,832	$	8,958	$	12,736
	Earnings allocated to participating securities	—		—		—
	Earnings available for common stockholders	$	14,832	$	8,958	$	12,736
	Denominator for basic net income per share of Class A common stock
	Weighted average shares of Class A common stock	32,789		24,086		16,567
	Add dilutive effect of the following:
	Stock options	616		—		—
	Lucid contingently issuable shares	552		—		—
	Convertible note hedges	—		—		—
	Warrants	—		—		—
	Assumed conversion of Holding Units for	—		—		—
	Class A common stock
	Dilutive weighted average shares of Class A common stock	33,957		24,086		16,567
	Basic income per share of Class A common stock	$	0.45	$	0.37	$	0.77
	Diluted income per share of Class A common stock	$	0.44	$	0.37	$	0.77

Related_Party_Transactions_Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2013
Related Party Transactions [Abstract]	'
Amounts receivable from, and payable to, related parties	'
	Amounts receivable from, and payable to, related parties are set forth below, with amounts in millions:
		December 31, 2013		December 31, 2012
	Receivables
	Advances to partners	$	0.9	$	—
	Advances to employees	0.8		0.9
		$	1.7	$	0.9
	Payables
	Guaranty agreements	$	8.4	$	9
	Employees	0.7		0.3
	Shareholders with greater than 5% ownership in the Company	0.2		0.7
	Due to Lucid non-controlling members in connection with the allocation of net income to Lucid non-controlling members for services provided	9.8		—
	Due to Lucid non-controlling members in connection with trade settlements	0.2		9.6
	Notes payable to Lucid non-controlling members in connection with the Acquisition	9.8		22.9
	Tax receivable agreement	150.3		100.8
	Follow-on Payment	3.7		—
		$	183.1	$	143.3

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Schedule of Share-based Compensation, Stock Options, Activity	'
	The following table summarizes the Company's stock options activity as of December 31, 2013 and changes for the year then ended:
	Options	Shares			Weighted-Average Exercise Price				Weighted-Average Remaining Contractual Term
	Outstanding at January 1, 2013	9,178,128			$	13.37			2.1
	Granted	531,636			$	14.87
	Exercised	(1,702,714	)		$	13.21
	Forfeited or expired	(399,250	)		$	13.78
	Outstanding as of December 31, 2013	7,607,800			$	13.48			4.3
	Vested or expected to vest at December 31, 2013	7,485,369			$	13.49			4.3
	Exercisable as of December 31, 2013	4,445,164			$	13.77			4
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions	'
	Assumptions used in the Black Scholes valuation model were as follows:
		Employee Stock Options											Independent Directors Options
		For the Years Ended											For the Years Ended
		2013				2012				2011			2013			2012			2011
	Expected term in years	4.75				4.75				4.75			4			4			N/A
	Risk-free interest rate	1.06		%		0.71		%		0.96		%	0.63		%	0.6		%	N/A
	Expected volatility	51		%		52		%		56		%	54		%	63		%	N/A
	Dividend yield	1.55		%		2.48		%		2.24		%	2.05		%	2.4		%	N/A
	Estimated fair value at grant date	$	6.02			$	3.47			$	4.26		$	4.26		$	4.11		N/A

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Schedule of Stockholders Equity	'
	The following table presents the changes in the Company’s Class A common stock shares outstanding during the year ended December 31, 2013, with amounts in thousands:
	Class A Common Stock	As of
		December 31, 2013
	Balance at January 1, 2013	34,684
	Issued	—
	Repurchased	(1,816	)
	Exchange of Holdings units into Class A common stock	10,094
	Stock options exercised	1,703
	Balance at December 31, 2013	44,665

Net_Capital_Requirements_Table

Net Capital Requirements (Tables)	12 Months Ended
	Dec. 31, 2013
Banking and Thrift [Abstract]	'
Minimum Capital Requirement And the Excess Capital	'
	The tables below present the capital, as defined by the respective regulatory authority, the minimum capital requirement and the excess capital for US, HK, UK, Australia, ODL, FSL, FXCMJ, Lucid LLP and Faros as of December 31, 2013 and 2012, with amounts in millions:
		December 31, 2013
		US		HK		UK		Australia		ODL		FSL		FXCMJ		Lucid LLP		Faros
	Capital	$	64.2	$	33.6	$	86	$	4.7	$	18.4	$	34.8	$	36.3	$	41.8	$	0.1
	Minimum capital requirement	27.1		12.3		24.7		0.4		6.9		8.2		5.6		4.2		—
	Excess capital	$	37.1	$	21.3	$	61.3	$	4.3	$	11.5	$	26.6	$	30.7	$	37.6	$	0.1
		December 31, 2012
		US		HK		UK		Australia		ODL		FSL		FXCMJ
	Capital	$	53.5	$	22.7	$	73.1	$	4.2	$	14.1	$	30.7	$	33.5
	Minimum capital requirement	26.1		8.1		17.4		1.2		4.4		4.4		5.6
	Excess capital	$	27.4	$	14.6	$	55.7	$	3	$	9.7	$	26.3	$	27.9

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Schedule of Future Minimum Rental Payments for Operating Leases	'
	Future minimum lease payments under non-cancelable operating leases with terms in excess of one year are as follows as of December 31, 2013, with amounts in thousands:
	Year Ending December 31,	As of
		December 31, 2013
	2014	$	7,186
	2015	5,847
	2016	4,685
	2017	3,807
	2018	3,612
	Thereafter	23,240
		$	48,377

Debt_Tables

Debt (Tables)	12 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Applicable Margin and Commitment Fees	'
	The applicable margin and commitment fees are set forth in the table below:
	Consolidated Leverage Ratio	Commitment Fee			Applicable Margin for Eurodollar Loans		Applicable Margin for Base Rate Loans
	Less than .50 to 1.00	0.25	%		1.75	%	0.75	%
	Greater than or equal to 0.50 to 1.00 but less than 1.00 to 1.00	0.3	%		2	%	1	%
	Greater than or equal to 1.00 to 1.00 but less than 1.50 to 1.00	0.35	%		2.25	%	1.25	%
	Greater than or equal to 1.50 to 1.00, but less than 2.00 to 1.00	0.4	%		2.5	%	1.5	%
	Greater than or equal to 2.00 to 1.00	0.45	%		2.75	%	1.75	%
Convertible Debt	'
	The balances of the liability and equity components as of December 31, 2013, were as follows, with amounts in thousands:
		December 31, 2013
	Liability component - principal	$	172,500
	Deferred bond discount	(26,197		)
	Liability component - net carrying value	$	146,303
	Equity component	$	29,101
	Interest expense related to the Convertible Notes, included in Interest on borrowings in the consolidated statements of operations was as follows, with amounts in thousands:
		Year Ended December 31, 2013
	Interest expense - stated coupon rate	$	2,232
	Interest expense - amortization of deferred bond discount	2,904
	Interest expense - amortization of debt issuance cost	699
	Total interest expense - Convertible Notes	$	5,835

Derivative_Financial_Instrumen1

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Offsetting Assets	'
	Under ASC 210, gross positive fair values are offset against gross negative fair values by counterparty pursuant to enforceable master netting agreements, with amounts in thousands:
		Derivatives Classified
		in Due from/to brokers
		December 31, 2013
		Assets			Liabilities			Net
	Gross fair values	$	84		$	(2,404	)	$	(2,320	)
	Netting agreements	(84		)	84			—
	Net fair values	$	—		$	(2,320	)	$	(2,320	)
		Derivatives Classified
		in Due from/to brokers
		December 31, 2012
		Assets			Liabilities			Net
	Gross fair values	$	520		$	(265	)	$	255
	Netting agreements	(265		)	265			—
	Net fair values	$	255		$	—		$	255
Offsetting Liabilities	'
	Under ASC 210, gross positive fair values are offset against gross negative fair values by counterparty pursuant to enforceable master netting agreements, with amounts in thousands:
		Derivatives Classified
		in Due from/to brokers
		December 31, 2013
		Assets			Liabilities			Net
	Gross fair values	$	84		$	(2,404	)	$	(2,320	)
	Netting agreements	(84		)	84			—
	Net fair values	$	—		$	(2,320	)	$	(2,320	)
		Derivatives Classified
		in Due from/to brokers
		December 31, 2012
		Assets			Liabilities			Net
	Gross fair values	$	520		$	(265	)	$	255
	Netting agreements	(265		)	265			—
	Net fair values	$	255		$	—		$	255

Fair_Value_Measurements_Fair_V

Fair Value Measurements Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	'
	The following table presents the Company's assets and liabilities that are measured at fair value on a recurring basis and the related hierarchy levels, with amounts in thousands:
		Fair Value Measurements on a Recurring Basis
		As of December 31, 2013
		Quoted Prices in Active Markets for Identical Assets (Level I)		Significant Observable Inputs (Level II)		Significant Unobservable Inputs (Level III)			Total
	Financial Assets:
	Cash and cash equivalents	$	365,245	$	—	$	—		$	365,245
	Cash and cash equivalents, held for customers	1,190,880		—		—			1,190,880
	Total assets	$	1,556,125	$	—	$	—		$	1,556,125
	Financial Liabilities:
	Customer account liabilities	$	1,190,880	$	—	$	—		$	1,190,880
	Due to brokers- open futures contracts	2,320		—		—			2,320
	Follow-on Payment	—		—		3,672			3,672
	Total liabilities	$	1,193,200	$	—	$	3,672		$	1,196,872
		Fair Value Measurements on a Recurring Basis
		As of December 31, 2012
		Quoted Prices in Active Markets for Identical Assets (Level I)		Significant Observable Inputs (Level II)		Significant Unobservable Inputs (Level III)			Total
	Financial Assets:
	Cash and cash equivalents	$	272,332	$	—	$	—		$	272,332
	Cash and cash equivalents, held for customers	1,190,762		—		—			1,190,762
	Due from brokers- open futures contracts	255		—		—			255
	Total assets	$	1,463,349	$	—	$	—		$	1,463,349
	Financial Liabilities:
	Customer account liabilities	$	1,190,762	$	—	$	—		$	1,190,762
	Total liabilities	$	1,190,762	$	—	$	—		$	1,190,762
Fair Value, by Balance Sheet Grouping	'
	The following table presents the carrying value, fair value and fair value hierarchy category of certain financial instruments that are not measured at fair value in the consolidated statements of financial condition, with amounts in thousands:
		As of December 31, 2013				Fair Value Measurements using:
		Carrying Value		Fair Value		Quoted Prices in Active Markets for Identical Assets (Level I)			Significant Observable Inputs (Level II)		Significant Unobservable Inputs (Level III)
	Financial Assets:
	Due from brokers- unsettled spot FX	$	5,450	$	5,450	$	5,450		$	—	$	—
	Equity method investments	9,793		13,504		—			—		13,504
	Notes receivable	11,942		11,942		—			—		11,942
	Total assets	$	27,185	$	30,896	$	5,450		$	—	$	25,446
	Financial Liabilities:
	Due to brokers- unsettled spot FX	$	6,332	$	6,332	$	6,332		$	—	$	—
	Notes payable	9,800		9,800		—			—		9,800
	Senior convertible notes	146,303		149,418		—			149,418		—
	Total liabilities	$	162,435	$	165,550	$	6,332		$	149,418	$	9,800
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	'
	The following table reconciles the ending balances of liabilities classified as Level III and identifies the total gains (losses) the Company recognized during the year ended December 31, 2013 on such liabilities that were included in the consolidated statements of financial condition as of December 31, 2013, respectively with amounts in thousands:
		Beginning Balance		Additions		Net Unrealized/Realized (Gains) Losses			Total
	Follow-on Payment	$	—	$	10,631	$	(6,959	)	$	3,672
	Total Level III liabilities	$	—	$	10,631	$	(6,959	)	$	3,672

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Schedule of Income before Income Tax, Domestic and Foreign	'
	Income before income taxes, as shown in the consolidated statements of operations, includes the following income components, with amounts in thousands:
		Years Ended December 31,
		2013				2012				2011
	Domestic	$	10,390			$	19,794			$	29,035
	Foreign	41,470				27,670				40,562
		$	51,860			$	47,464			$	69,597
Schedule of Components of Income Tax Expense (Benefit)	'
	The provision for income taxes consists of the following, with amounts in thousands:
		Year Ended December 31,
		2013				2012				2011
	Current
	Federal income tax (benefit)	$	(185	)		$	478			$	238
	State and local income tax	682				574				1,384
	Foreign income tax	5,085				764				9,268
	Subtotal	$	5,582			$	1,816			$	10,890
	Deferred
	Federal income tax	$	3,996			$	2,837			$	7,578
	State and local income tax (benefit)	235				(171		)		(1,802		)
	Foreign income tax (benefit)	7,211				4,504				(5,850		)
	Subtotal	$	11,442			$	7,170			$	(74	)
	Total provision for taxes	$	17,024			$	8,986			$	10,816
Schedule of Effective Income Tax Rate Reconciliation	'
	The following table reconciles the provision for income taxes to the U.S. federal statutory tax rate:
		Year Ended December 31,
		2013			2012			2011
	Statutory U.S. federal income tax rate	34	%		34	%		34	%
	Income passed through to non-controlling members	(5.4	)		(15.5	)		(13.0	)
	State and local income tax	0.9			1			2.1
	Foreign income tax	(1.4	)		(3.1	)		(0.2	)
	Release of valuation allowance	—			—			(11.8	)
	Non- deductible FCA fine	2			—			—
	Foreign tax credit valuation allowance	3.5			2.5			0.8
	Impact of rate change on deferred tax assets	(0.9	)		—			4
	Other	0.1			—			(0.4	)
	Effective tax rate	32.8	%		18.9	%		15.5	%
Schedule of Deferred Tax Assets and Liabilities	'
	A summary of the tax effects of the temporary differences is as follows, with amounts in thousands:
		Years Ended December 31,
		2013				2012
	Deferred tax assets
	Equity based compensation	$	1,059			$	1,259
	Investment in partnership	178,941				118,327
	Fixed assets	2,279				4,009
	Tax loss carryforwards	25,631				7,761
	Tax credit carryforward/foreign sub income	4,265				2,083
	Japan software	1,516				3,083
	Other	577				140
	Gross deferred tax assets	$	214,268			$	136,662
	Less: valuation allowance	(25,288		)		(8,843		)
	Net deferred tax asset	$	188,980			$	127,819
	Deferred tax liabilities
	Fixed assets	$	4			$	65
	Intangible assets	3,965				6,292
	Goodwill	8,742				12,563
	Software development cost	238				193
	Other	1,232				338
	Gross deferred tax liabilities	$	14,181			$	19,451
	Net deferred tax asset	$	174,799			$	108,368
Schedule of Unrecognized Tax Benefits Roll Forward	'
	The following is a tabular reconciliation of the total amounts of unrecognized tax benefits, with amounts in thousands:
		2013				2012				2011
	Unrecognized tax benefits – January 1	$	3,691			$	223			$	—
	Gross increases – tax positions in prior period	—				1				44
	Gross decreases – tax positions in prior period	(3,445		)		(16		)		—
	Gross increases – tax positions in current period	51				3,483				179
	Settlement	(114		)		—				—
	Lapse of statute of limitations	—				—				—
	Unrecognized tax benefits – December 31	$	183			$	3,691			$	223

Segments_Tables

Segments (Tables)	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Schedule of Segment Reporting Information, by Segment	'
	Information concerning the Company’s operations by reportable segment is as follows, with amounts in thousands:
		As of and For the
		Year Ended December 31, 2013
		Retail Trading			Institutional Trading			Corporate			Total
	Total net revenues	$	379,840		$	110,957		$	(1,209	)	$	489,588
	Operating and other expenses	219,016			99,536			119,176			437,728
	Income (loss) before income taxes	$	160,824		$	11,421		$	(120,385	)	$	51,860
	Assets	$	1,622,829		$	417,492		$	183,626		$	2,223,947
		As of and For the
		Year Ended December 31, 2012
		Retail Trading			Institutional Trading			Corporate			Total
	Total net revenues	$	355,282		$	62,033		$	—		$	417,315
	Operating and other expenses	218,018			45,164			106,669			369,851
	Income (loss) before income taxes	$	137,264		$	16,869		$	(106,669	)	$	47,464
	Assets	$	1,556,680		$	381,368		$	127,122		$	2,065,170
		As of and For the
		Year Ended December 31, 2011
		Retail Trading			Institutional Trading			Corporate			Total
	Total net revenues	$	383,356		$	28,908		$	3,314		$	415,578
	Operating and other expenses	218,534			20,784			106,663			345,981
	Income (loss) before income taxes	$	164,822		$	8,124		$	(103,349	)	$	69,597
	Assets	$	1,361,577		$	9,534		$	116,022		$	1,487,133
		Years Ended December 31,
		2013			2012			2011
	Total Net Revenues
	United States	$	301,005		$	284,511		$	329,366
	Asia	57,557			51,486			27,960
	Europe, Middle East and North Africa	286,771			191,314			165,073
	Other	4,811			4,183			5,098
	Eliminations	(160,556		)	(114,179		)	(111,919		)
	Total	$	489,588		$	417,315		$	415,578
		Years Ended December 31,
		2013			2012			2011
	Operating and Other Expenses
	United States	$	290,549		$	264,706		$	299,841
	Asia	39,410			41,228			24,173
	Europe, Middle East and North Africa	265,218			173,467			130,254
	Other	3,107			3,214			3,632
	Eliminations	(160,556		)	(112,764		)	(111,919		)
	Total	$	437,728		$	369,851		$	345,981
		Years Ended December 31,
		2013			2012			2011
	Income Before Income Taxes
	United States	$	10,456		$	19,805		$	29,525
	Asia	18,147			10,258			3,787
	Europe, Middle East and North Africa	21,553			17,847			34,819
	Other	1,704			969			1,466
	Eliminations	—			(1,415		)	—
	Total	$	51,860		$	47,464		$	69,597
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas	'
	Information concerning the Company’s operations by reportable segment is as follows, with amounts in thousands:
		As of and For the
		Year Ended December 31, 2013
		Retail Trading			Institutional Trading			Corporate			Total
	Total net revenues	$	379,840		$	110,957		$	(1,209	)	$	489,588
	Operating and other expenses	219,016			99,536			119,176			437,728
	Income (loss) before income taxes	$	160,824		$	11,421		$	(120,385	)	$	51,860
	Assets	$	1,622,829		$	417,492		$	183,626		$	2,223,947
		As of and For the
		Year Ended December 31, 2012
		Retail Trading			Institutional Trading			Corporate			Total
	Total net revenues	$	355,282		$	62,033		$	—		$	417,315
	Operating and other expenses	218,018			45,164			106,669			369,851
	Income (loss) before income taxes	$	137,264		$	16,869		$	(106,669	)	$	47,464
	Assets	$	1,556,680		$	381,368		$	127,122		$	2,065,170
		As of and For the
		Year Ended December 31, 2011
		Retail Trading			Institutional Trading			Corporate			Total
	Total net revenues	$	383,356		$	28,908		$	3,314		$	415,578
	Operating and other expenses	218,534			20,784			106,663			345,981
	Income (loss) before income taxes	$	164,822		$	8,124		$	(103,349	)	$	69,597
	Assets	$	1,361,577		$	9,534		$	116,022		$	1,487,133
		Years Ended December 31,
		2013			2012			2011
	Total Net Revenues
	United States	$	301,005		$	284,511		$	329,366
	Asia	57,557			51,486			27,960
	Europe, Middle East and North Africa	286,771			191,314			165,073
	Other	4,811			4,183			5,098
	Eliminations	(160,556		)	(114,179		)	(111,919		)
	Total	$	489,588		$	417,315		$	415,578
		Years Ended December 31,
		2013			2012			2011
	Operating and Other Expenses
	United States	$	290,549		$	264,706		$	299,841
	Asia	39,410			41,228			24,173
	Europe, Middle East and North Africa	265,218			173,467			130,254
	Other	3,107			3,214			3,632
	Eliminations	(160,556		)	(112,764		)	(111,919		)
	Total	$	437,728		$	369,851		$	345,981
		Years Ended December 31,
		2013			2012			2011
	Income Before Income Taxes
	United States	$	10,456		$	19,805		$	29,525
	Asia	18,147			10,258			3,787
	Europe, Middle East and North Africa	21,553			17,847			34,819
	Other	1,704			969			1,466
	Eliminations	—			(1,415		)	—
	Total	$	51,860		$	47,464		$	69,597

Nature_of_Business_and_Organiz1

Nature of Business and Organization - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2013	Jun. 18, 2012
		Lucid Markets Trading Limited	Lucid Markets Trading Limited
Basis of Presentation [Line Items]	'	'	'
Entity Incorporation, Date of Incorporation	10-Aug-10	'	'
Acquisition of controlling interest	'	50.10%	50.10%

Reorganization_and_IPO_Additio

Reorganization and IPO - Additional Information (Detail) (USD $)	12 Months Ended		12 Months Ended	11 Months Ended
	Dec. 31, 2013	Dec. 06, 2010	Dec. 31, 2013	Dec. 06, 2010
			Common Class A	Common Class A
			vote	IPO
Reorganization and IPO Disclosure [Line Items]	'	'	'	'
Votes per common share	'	'	1	'
IPO of class A common stock, offering price	'	'	'	$14
Percentage of capital	'	50.00%	'	'
Percentage of benefits to Holding members	85.00%	'	'	'

Significant_Accounting_Policie3

Significant Accounting Policies and Estimates - Additional Information (Detail) (USD $)

12 Months Ended

12 Months Ended

0 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2011

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Sep. 20, 2013

Sep. 20, 2013

Sep. 20, 2013

Dec. 31, 2013

Dec. 31, 2012

Other Income

Other Income

Settlement with FCA

Customer relationships

Customer relationships

Noncompete Agreements

Noncompete Agreements

Trade Names

Proprietary Technology

Proprietary Technology

Lucid Markets Trading Limited

Lucid Markets Trading Limited

Faros Trading LLC

Faros Trading LLC

Faros Trading LLC

Faros Trading LLC

FXCM Holdings, LLC

FXCM Holdings, LLC

Positive Outcome of Litigation

General and Administrative Expense

Minimum

Maximum

Minimum

Maximum

Minimum

Maximum

Noncompete Agreements

Other Income

Customer relationships

Noncompete Agreements

Trade Names

Significant Accounting Policies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of voting interests

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

54.80%

42.50%

Equity interest

'

'

'

'

'

'

'

'

'

'

'

'

'

49.90%

'

'

'

'

'

45.20%

57.50%

Restricted cash and cash equivalents

$1,000,000,000

$1,000,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Goodwill impairment loss

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Intangible asset amortization period

'

'

'

'

'

'

'4 years

'9 years

'3 years

'9 years

'3 years

'4 years

'7 years

'

'3 years

'

'4 years

'9 years

'3 years

'

'

Impairment of finite-lived intangible assets

0

0

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Foreign currency transactions gain

5,300,000

800,000

3,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Remeasurement gain

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

7,000,000

'

'

'

'

'

Remeasurement due to tax receivable

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,200,000

'

'

'

'

'

Settlement

'

'

'

'

1,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Other income

'

'

'

4,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Other noncash income (expense)

4,079,000

0

0

3,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Liability established pertaining to a settlement with FCA

'

'

'

'

'

$16,600,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Useful_Lives_of_Assets_Detail

Useful Lives of Assets (Detail)	12 Months Ended
	Dec. 31, 2013
Computer equipment | Minimum	'
Property, Plant and Equipment, Estimated Useful Lives, Lease Terms [Line Items]	'
Property plant and equipment estimated useful lives	'3 years
Computer equipment | Maximum	'
Property, Plant and Equipment, Estimated Useful Lives, Lease Terms [Line Items]	'
Property plant and equipment estimated useful lives	'5 years
Software | Minimum	'
Property, Plant and Equipment, Estimated Useful Lives, Lease Terms [Line Items]	'
Property plant and equipment estimated useful lives	'2 years
Software | Maximum	'
Property, Plant and Equipment, Estimated Useful Lives, Lease Terms [Line Items]	'
Property plant and equipment estimated useful lives	'5 years
Leasehold improvements	'
Property, Plant and Equipment, Estimated Useful Lives, Lease Terms [Line Items]	'
Property plant and equipment estimated useful lives	'Lesser of the estimated economic useful life or the term of the lease
Furniture and fixtures and other equipment | Minimum	'
Property, Plant and Equipment, Estimated Useful Lives, Lease Terms [Line Items]	'
Property plant and equipment estimated useful lives	'3 years
Furniture and fixtures and other equipment | Maximum	'
Property, Plant and Equipment, Estimated Useful Lives, Lease Terms [Line Items]	'
Property plant and equipment estimated useful lives	'5 years
Licenses | Minimum	'
Property, Plant and Equipment, Estimated Useful Lives, Lease Terms [Line Items]	'
Property plant and equipment estimated useful lives	'2 years
Licenses | Maximum	'
Property, Plant and Equipment, Estimated Useful Lives, Lease Terms [Line Items]	'
Property plant and equipment estimated useful lives	'3 years
Communication equipment | Minimum	'
Property, Plant and Equipment, Estimated Useful Lives, Lease Terms [Line Items]	'
Property plant and equipment estimated useful lives	'3 years
Communication equipment | Maximum	'
Property, Plant and Equipment, Estimated Useful Lives, Lease Terms [Line Items]	'
Property plant and equipment estimated useful lives	'5 years

Change_in_Interest_Holdings_of

Change in Interest Holdings of Corporation and Non-Controlling Interest (Detail)	12 Months Ended
	Dec. 31, 2013
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Shares [Roll Forward]	'
Exercise of stock options	1,702,714
Controlling Units	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Shares [Roll Forward]	'
Balance at January 1, 2013	34,683,599
Holding Units repurchased related to Class A common stock repurchased	-1,815,800
Exercise of stock options	1,702,714
Balance at December 31, 2013	44,664,884
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Percent [Roll Forward]	'
Balance as of January 1, 2013	42.50%
Holding Units repurchased related to Class A common stock repurchased	-0.80%
Holding Units acquired by FXCM Inc. related to exchanges of Holding Units for shares of Class A common stock	12.30%
Exercise of stock options	0.80%
Balance as of December 31, 2013	54.80%
Non- Controlling Units	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Shares [Roll Forward]	'
Balance at January 1, 2013	46,930,192
Holding Units repurchased related to Class A common stock repurchased	0
Holding Units acquired by FXCM Inc. related to exchanges of Holding Units for shares of Class A common stock	-10,094,371
Exercise of stock options	0
Balance at December 31, 2013	36,835,821
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Percent [Roll Forward]	'
Balance as of January 1, 2013	57.50%
Holding Units repurchased related to Class A common stock repurchased	0.80%
Holding Units acquired by FXCM Inc. related to exchanges of Holding Units for shares of Class A common stock	-12.30%
Exercise of stock options	-0.80%
Balance as of December 31, 2013	45.20%
Total Units	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Shares [Roll Forward]	'
Balance at January 1, 2013	81,613,791
Holding Units repurchased related to Class A common stock repurchased	-1,815,800
Holding Units acquired by FXCM Inc. related to exchanges of Holding Units for shares of Class A common stock	0
Exercise of stock options	1,702,714
Balance at December 31, 2013	81,500,705
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Percent [Roll Forward]	'
Balance as of January 1, 2013	100.00%
Balance as of December 31, 2013	100.00%

Business_Acquisition_Additiona

Business Acquisition - Additional Information (Detail) (USD $)

12 Months Ended

0 Months Ended

0 Months Ended

3 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 21, 2012

Dec. 21, 2013

Dec. 31, 2013

Sep. 20, 2013

Dec. 31, 2013

Dec. 31, 2013

Jun. 18, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Jun. 18, 2012

Jun. 18, 2012

Jun. 18, 2012

Dec. 31, 2013

Dec. 21, 2012

Jun. 18, 2012

Jun. 18, 2012

Oct. 07, 2011

Dec. 31, 2013

Dec. 31, 2011

Mar. 31, 2011

Dec. 31, 2013

Dec. 31, 2011

Unsecured Promissory Note

Unsecured Promissory Note

Faros Trading LLC

Faros Trading LLC

Faros Trading LLC

Lucid Markets Trading Limited

Lucid Markets Trading Limited

Lucid Markets Trading Limited

Lucid Markets Trading Limited

Lucid Markets Trading Limited

Lucid Markets Trading Limited

Lucid Markets Trading Limited

Lucid Markets Trading Limited

Lucid Markets Trading Limited

Lucid Markets Trading Limited

Lucid Markets Trading Limited

Lucid Markets Trading Limited

Foreland

Foreland

Foreland

Fxcm Japan

Fxcm Japan

Fxcm Japan

Maximum

Minimum

Class A common stock

Shares at Closing

Shares Held in Escrow

Unsecured Promissory Note

Unsecured Promissory Note

Unsecured Promissory Note

Unsecured Promissory Note

$71.4 million 3.5% Unsecured Promissory Note

$15.8 million 3.5% Unsecured Promissory Note

Business Acquisition [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Acquisition of controlling interest

'

'

'

'

'

'

50.10%

'

'

50.10%

50.10%

'

'

'

'

'

'

'

'

'

'

100.00%

'

'

100.00%

'

'

Cost of acquired entity, cash paid

'

'

'

'

'

'

$5,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contingent liability

'

'

'

'

'

'

10,600,000

3,700,000

3,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Purchase price

'

'

'

'

'

'

15,631,000

'

'

177,500,000

192,784,000

[1]

'

'

'

'

'

'

'

'

'

'

37,700,000

37,654,000

'

15,700,000

15,725,000

'

Business acquisition equity interest issued remaining shares fair value

'

'

'

'

'

'

400,000

'

'

67,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fair value of controlling interest, discount rate

'

'

'

'

'

'

25.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Adjustment to follow-on payment for business acquisition

-6,959,000

0

0

'

'

'

'

7,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Goodwill adjustment/remeasurement

191,000

'

'

'

'

'

'

'

800,000

'

-1,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Goodwill

307,936,000

285,654,000

'

'

'

'

23,033,000

23,000,000

23,000,000

236,500,000

235,317,000

[1]

'

'

'

'

'

'

'

'

'

'

10,000,000

9,995,000

'

800,000

766,000

'

Non-Controlling interest

'

'

'

'

'

'

15,569,000

'

'

'

160,165,000

[1]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term annual earnings growth rate

'

'

'

'

'

'

3.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Face amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

71,400,000

15,800,000

'

'

'

'

'

'

Interest rate on promissory notes

'

'

'

2.25%

2.25%

2.25%

'

'

'

'

'

'

'

'

'

'

'

2.25%

3.50%

3.50%

3.50%

'

'

'

'

'

'

Issuance of shares for acquisition

'

'

'

'

'

'

'

'

'

9,000,000

'

'

'

'

'

1,800,000

7,200,000

'

'

'

'

'

'

'

'

'

'

Period for share issuance

'

'

'

'

'

'

'

'

'

'3 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Time limit for purchase of buy back of shares

'

'

'

'

'

'

'

'

'

'30 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fair value of the shares issued for acquisition

'

'

'

'

'

'

'

'

'

89,400,000

'

'

'

'

21,500,000

'

'

'

'

'

'

'

'

'

'

'

'

Deferred compensation liability

'

'

'

'

'

'

'

'

'

9,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Assumed discount rates ,in estimate of fair value of non controlling interest

'

'

'

'

'

'

'

'

'

'

'

'

11.00%

10.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

Annual earnings growth rate

'

'

'

'

'

'

'

'

'

'

4.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Increase in purchase price

'

'

'

'

'

'

'

'

'

'

15,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Term

'

'

'

'

'6 months

'

'

'

'

'

'

'

'

'

'

'

'

'6 months

'

'

'

'

'

'

'

'

'

Expected tax deductible goodwill

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0

'

'

0

'

'

Acquisition-related transaction costs

'

'

'

'

'

'

'

'

'

'

'

$900,000

'

'

'

'

'

'

'

'

'

'

'

$200,000

'

'

$300,000

[1]

The amounts included in the Lucid Purchase Price Allocation table represent the allocation of the purchase price and includes revisions made during the 12 months remeasurement period from the Acquisition Date.

Purchase_Price_Allocation_Deta

Purchase Price Allocation (Detail) (USD $)

Dec. 31, 2013

Dec. 31, 2012

Sep. 20, 2013

Dec. 31, 2013

Sep. 20, 2013

Sep. 20, 2013

Sep. 20, 2013

Jun. 18, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Oct. 07, 2011

Dec. 31, 2013

Dec. 31, 2013

Mar. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

In Thousands, unless otherwise specified

Faros Trading LLC

Faros Trading LLC

Faros Trading LLC

Faros Trading LLC

Faros Trading LLC

Lucid Markets Trading Limited

Lucid Markets Trading Limited

Lucid Markets Trading Limited

Lucid Markets Trading Limited

Foreland

Foreland

Foreland

Fxcm Japan

Fxcm Japan

Fxcm Japan

Customer relationships

Noncompete Agreements

Trade Names

Noncompete Agreements

Proprietary technology

Customer relationships

Customer relationships

Business Combination Allocation of Purchase Price [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Purchase price

'

'

$15,631

'

'

'

'

$177,500

$192,784

[1]

'

'

$37,700

$37,654

'

$15,700

$15,725

'

Net assets acquired

'

'

137

'

'

'

'

'

32,732

[1]

'

'

'

21,460

'

'

14,301

'

Non-Controlling interest

'

'

15,569

'

'

'

'

'

160,165

[1]

'

'

'

'

'

'

'

'

Total fair value at Acquisition Date

'

'

31,200

'

'

'

'

'

352,949

[1]

'

'

'

'

'

'

'

'

Adjustments to reflect acquired assets and liabilities at fair value

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Intangible Assets

'

'

'

'

6,000

[2]

1,900

[3]

130

[4]

'

'

1,000

[1],[5]

83,900

[1],[6]

'

'

9,925

[7]

'

'

1,055

[7]

Deferred tax liability

'

'

'

'

'

'

'

'

'

'

'

-3,726

-3,726

'

-397

-397

'

Fair value of net assets acquired

'

'

8,167

'

'

'

'

117,632

117,632

[1]

'

'

27,659

27,659

'

14,959

14,959

'

Goodwill resulting from the Foreland acquisition

$307,936

$285,654

$23,033

$23,000

'

'

'

$236,500

$235,317

[1]

'

'

$10,000

$9,995

'

$800

$766

'

[1]

The amounts included in the Lucid Purchase Price Allocation table represent the allocation of the purchase price and includes revisions made during the 12 months remeasurement period from the Acquisition Date.

[2]

Consists of institutional and bank customers, with an amortization life of 4 years.

[3]

Amortization life is 9 years.

[4]

Amortization life is 3 years.

[5]

Consists of two non-compete agreements with amortization lives of 3 years.

[6]

Consists of internally developed software platforms through which the Company: (i) executes its specific trading strategies, with an amortization life of 4 years and (ii) clears and efficiently settle trades, with an amortization life of 7 years.

[7]

Consists of retail customers. The amortization life is 6 years.

Purchase_Price_Allocation_Pare

Purchase Price Allocation (Parenthetical) (Detail)	12 Months Ended	0 Months Ended			12 Months Ended
	Dec. 31, 2013	Sep. 20, 2013	Sep. 20, 2013	Sep. 20, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013
	Trade Names	Faros Trading LLC	Faros Trading LLC	Faros Trading LLC	Lucid Markets Trading Limited	Lucid Markets Trading Limited	Lucid Markets Trading Limited	Lucid Markets Trading Limited	Foreland	Fxcm Japan
		Customer relationships	Noncompete Agreements	Trade Names		Noncompete Agreements	Core Trading Platform	Post Trade Processing Platform	Customer relationships	Customer relationships
						asset
Business Combination Allocation of Purchase Price [Line Items]	'	'	'	'	'	'	'	'	'	'
Number of Non-Compete agreements	'	'	'	'	'	2	'	'	'	'
Intangible asset amortization period	'3 years	'4 years	'9 years	'3 years	'	'3 years	'4 years	'7 years	'6 years	'6 years
Remeasurement period	'	'	'	'	'12 months	'	'	'	'	'

Condensed_Statement_of_Net_Ass

Condensed Statement of Net Assets Acquired (Detail) (USD $)	Sep. 20, 2013	Dec. 31, 2013		Jun. 18, 2012	Dec. 31, 2013	Oct. 07, 2011	Dec. 31, 2013	Mar. 31, 2011
In Thousands, unless otherwise specified	Faros Trading LLC	Lucid Markets Trading Limited		Lucid Markets Trading Limited	Foreland	Foreland	Fxcm Japan	Fxcm Japan
Assets	'	'		'	'	'	'	'
Cash and cash equivalents	$1,055	'		$28,656	'	$29,853	'	$9,827
Cash and cash equivalents, held for customers	'	'		'	'	172,826	'	114,024
Due from broker	'	'		'	'	'	'	3,885
Accounts receivable, net	40	'		5,100	'	501	'	194
Tax receivable	'	'		'	'	'	'	478
Office, communication and computer equipment, net	31	'		499	'	847	'	2,279
Intangible assets	8,030	'		84,900	'	9,934	'	1,064
Due from brokers	'	'		302	'	'	'	'
Deferred tax asset	'	'		11,311	'	'	'	'
Other assets	76	'		226	'	1,199	'	1,189
Total assets	9,232	'		130,994	'	215,160	'	132,940
Liabilities	'	'		'	'	'	'	'
Customer account liabilities	'	'		'	'	172,826	'	114,023
Accounts payable and accrued expenses	1,065	'		13,362	'	6,502	'	3,561
Due to brokers	'	'		'	'	4,447	'	'
Deferred tax liability	'	'		'	3,726	3,726	397	397
Total liabilities	1,065	'		13,362	'	187,501	'	117,981
Fair value of net assets acquired	$8,167	$117,632	[1]	$117,632	$27,659	$27,659	$14,959	$14,959
[1]	The amounts included in the Lucid Purchase Price Allocation table represent the allocation of the purchase price and includes revisions made during the 12 months remeasurement period from the Acquisition Date.

Condensed_Combined_Financial_I

Condensed Combined Financial Information (Detail) (USD $)	12 Months Ended			6 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012
				Lucid Markets Trading Limited
Business Combination, Separately Recognized Transactions [Line Items]	'	'	'	'
Total revenue	$489,588	$417,315	$415,578	$42,198
Net income	$14,832	$8,958	$12,736	$21,446

Pro_Forma_Condensed_Combined_F

Pro Forma Condensed Combined Financial Information of Acquisitions (Detail) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	Faros Trading LLC	Faros Trading LLC	Lucid Markets Trading Limited	Foreland and FXCM Japan
Business Acquisition [Line Items]	'	'	'	'
Total revenues	$526	$491,217	$463,767	$588,028
Net income before non-controlling interest	($301)	$32,463	$49,224	$115,884

Equity_Method_Investment_Addit

Equity Method Investment - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 04, 2012	Dec. 31, 2013
				Loss on Equity Method Investments, Net	Electric Communication Network for Foreign Exchange Trading	FX Trading Software Developer
Schedule of Equity Method Investments [Line Items]	'	'	'	'	'	'
Ownership percentage by parent	'	'	'	'	38.00%	'
Percentage of equity interest	'	'	'	'	'	26.30%
Equity method investments	$9,793,000	$12,000,000	'	'	'	'
Loss on equity method investments, net	752,000	0	0	800,000	'	'
Equity method dividends	'	$0	$0	'	'	'

Office_Communication_and_Compu2

Office, Communication and Computer Equipment, net (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]	'	'
Property plant and equipment	$100,064	$100,424
Less: Accumulated depreciation	-50,899	-50,108
Office, communication and computer equipment, net	49,165	50,316
Computer equipment	'	'
Property, Plant and Equipment [Line Items]	'	'
Property plant and equipment	28,047	34,541
Software	'	'
Property, Plant and Equipment [Line Items]	'	'
Property plant and equipment	47,138	31,476
Leasehold improvements	'	'
Property, Plant and Equipment [Line Items]	'	'
Property plant and equipment	9,687	9,478
Furniture and fixtures and other equipment	'	'
Property, Plant and Equipment [Line Items]	'	'
Property plant and equipment	3,427	3,185
Licenses	'	'
Property, Plant and Equipment [Line Items]	'	'
Property plant and equipment	10,101	20,222
Communication equipment	'	'
Property, Plant and Equipment [Line Items]	'	'
Property plant and equipment	$1,664	$1,522

Office_Communication_and_Compu3

Office, Communication and Computer Equipment, Net - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]	'	'	'
Depreciation	$25,800,000	$17,700,000	$13,100,000
Unamortized capitalized software development costs	26,000,000	20,300,000	'
Assets of Disposal Group, Including Discontinued Operation	19,200,000	2,900,000	'
Impairment of finite-lived intangible assets	0	0	0
Core Trading Platform	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Impairment of finite-lived intangible assets	3,500,000	'	'
Capitalized Computer Software	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Amortization cost	$10,600,000	$6,500,000	$3,000,000

Changes_in_Goodwill_by_Segment

Changes in Goodwill by Segment (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013
Goodwill [Roll Forward]	'
Balance at January 1, 2013	$285,654
Goodwill acquired	23,033
Goodwill adjustment/remeasurement	191
Foreign currency translation adjustment	-942
Balance at December 31, 2013	307,936
Retail Trading	'
Goodwill [Roll Forward]	'
Balance at January 1, 2013	37,851
Goodwill acquired	0
Goodwill adjustment/remeasurement	1,387
Foreign currency translation adjustment	-1,159
Balance at December 31, 2013	38,079
Institutional Trading	'
Goodwill [Roll Forward]	'
Balance at January 1, 2013	247,803
Goodwill acquired	23,033
Goodwill adjustment/remeasurement	-1,196
Foreign currency translation adjustment	217
Balance at December 31, 2013	$269,857

Acquired_Intangible_Assets_Det

Acquired Intangible Assets (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Acquired Indefinite-lived Intangible Assets [Line Items]	'	'
Indefinite-lived intangible assets	$610	$610
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross Carrying Amount	130,499	124,163
Accumulated Amortization	-54,396	-26,981
Net Carrying Amount	76,103	97,182
Customer relationships	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross Carrying Amount	37,746	32,269
Accumulated Amortization	-14,529	-9,815
Net Carrying Amount	23,217	22,454
Noncompete Agreements	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross Carrying Amount	10,507	8,214
Accumulated Amortization	-8,177	-5,841
Net Carrying Amount	2,330	2,373
Proprietary Technology	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross Carrying Amount	83,900	83,900
Accumulated Amortization	-31,849	-11,081
Net Carrying Amount	52,051	72,819
Trade Names	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross Carrying Amount	177	0
Accumulated Amortization	-13	0
Net Carrying Amount	164	0
Foreign Currency Translation	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Gross Carrying Amount	-1,831	-220
Accumulated Amortization	172	-244
Net Carrying Amount	-1,659	-464
Licenses	'	'
Acquired Indefinite-lived Intangible Assets [Line Items]	'	'
Indefinite-lived intangible assets	$610	$610

Other_Intangible_Assets_Net_Ad

Other Intangible Assets, Net - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Acquired Intangible Assets by Major Class [Line Items]	'	'	'
Intangible asset amortization expense	$27.90	$19	$6.90
Customer relationships | Minimum	'	'	'
Acquired Intangible Assets by Major Class [Line Items]	'	'	'
Intangible asset amortization period	'4 years	'	'
Customer relationships | Maximum	'	'	'
Acquired Intangible Assets by Major Class [Line Items]	'	'	'
Intangible asset amortization period	'9 years	'	'
Noncompete Agreements | Minimum	'	'	'
Acquired Intangible Assets by Major Class [Line Items]	'	'	'
Intangible asset amortization period	'3 years	'	'
Noncompete Agreements | Maximum	'	'	'
Acquired Intangible Assets by Major Class [Line Items]	'	'	'
Intangible asset amortization period	'9 years	'	'
Proprietary Technology | Minimum	'	'	'
Acquired Intangible Assets by Major Class [Line Items]	'	'	'
Intangible asset amortization period	'4 years	'	'
Proprietary Technology | Maximum	'	'	'
Acquired Intangible Assets by Major Class [Line Items]	'	'	'
Intangible asset amortization period	'7 years	'	'
Trade Names	'	'	'
Acquired Intangible Assets by Major Class [Line Items]	'	'	'
Intangible asset amortization period	'3 years	'	'

Estimated_Future_Amortization_

Estimated Future Amortization Expense for Acquired Intangible Assets Outstanding (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]	'	'
2014	$27,655	'
2015	27,431	'
2016	15,562	'
2017	3,068	'
2018	1,022	'
Thereafter	1,365	'
Net Carrying Amount	$76,103	$97,182

Notes_Receivable_Details

Notes Receivable (Details) (Infinium Capital, Notes Receivable, USD $)	Oct. 02, 2013
In Millions, unless otherwise specified	payment
Infinium Capital | Notes Receivable	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'
Interest rate	4.00%
Notes receivable	$11.90
Number of lump sum payments	2
Lump sum due on August 1, 2014	50.00%
Lump sum due on August 1, 2015	50.00%

Components_of_Other_Assets_Det

Components of Other Assets (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]	'	'
Prepaid expenses	$5,738	$5,439
Equity method investments	9,793	12,000
Deferred debt issuance costs	7,131	1,109
Deposits	1,492	1,555
Other	162	13
Other assets	$24,316	$20,116

Customer_Account_Liabilities_A

Customer Account Liabilities - Additional Information (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Other Liabilities Disclosure [Abstract]	'	'
Customer account liabilities	$1,190,880	$1,190,762

Recovered_Sheet1

Accounts payable and accrued expenses (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Payables and Accruals [Abstract]	'	'
Operating expenses payable	$41,528	$28,793
Due to Lucid non-controlling members	9,995	9,611
Commissions payable	9,485	8,126
Bonus payable	7,455	3,945
Income tax payable	1,046	1,231
Acquisition cash consideration payable	0	808
Interest due on borrowings	177	121
Other	11	0
Accounts payable and accrued expenses	$69,697	$52,635

Earnings_Per_Share_Additional_

Earnings Per Share - Additional Information (Detail) (USD $)

12 Months Ended

1 Months Ended

0 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 21, 2012

Jun. 30, 2013

Jun. 18, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

2.25% Senior Convertible Notes

Lucid Markets Trading Limited

Common Class A

Common Class A

Common Class A

Common Class A

Common Class A

Common Class A

Common Class A

Common Class A

Employee Stock Option

Employee Stock Option

Employee Stock Option

Employee Stock Option

Independent Directors Option

Independent Directors Option

Convertible Debt

Controlling Units

Controlling Units

Common Stock

Common Stock

Common Stock

Common Stock

Common Class A

Common Class A

Common Class A

Common Class A

Lucid Markets Trading Limited

Lucid Markets Trading Limited

Lucid Markets Trading Limited

Lucid Markets Trading Limited

First Anniversary

Second Anniversary

Third Anniversary

Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stock options granted to purchase shares (in shares)

531,636

'

'

'

'

'

'

'

'

'

'

'

'

'

426,000

725,000

105,636

109,488

Stock option granted excluded from computation of earnings per share

'

'

'

'

'

'

'

'

'

'

'

'

426,000

9,178,128

'

'

'

'

Issuance of shares for acquisition

'

'

'

9,000,000

'

'

'

'

7,200,000

1,200,000

3,000,000

3,000,000

'

'

'

'

'

'

Face amount

'

'

$172,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest rate

'

2.25%

2.25%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Conversion ratio

'

'

53.2992

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Conversion price (in dollars per share)

'

'

$18.76

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Holding Units acquired by FXCM Inc. related to exchanges of Holding Units for shares of Class A common stock

'

'

'

'

'

'

10,094,371

10,800,000

'

'

'

'

'

'

'

'

'

'

Conversion ratio

'

'

'

'

1

1

'

'

'

'

'

'

'

'

'

'

'

'

Reconciliation_of_Numerator_an

Reconciliation of Numerator and Denominator Used in Basic and Diluted EPS Calculations (Detail) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Denominator for basic net income per share of Class A common stock	'	'	'
Weighted average shares of Class A common stock	32,789	24,086	16,567
Add dilutive effect of the following:	'	'	'
Dilutive weighted average shares of Class A common stock	33,957	24,086	16,567
Basic income per share of Class A common stock (in dollars per share)	$0.45	$0.37	$0.77
Diluted income per share of Class A common stock (in dollars per share)	$0.44	$0.37	$0.77
Common Class A	'	'	'
Numerator	'	'	'
Net Income (Loss) Available to Common Stockholders, Basic	$14,832	$8,958	$12,736
Earnings allocated to participating securities	0	0	0
Net Income (Loss) Available to Common Stockholders, Diluted	$14,832	$8,958	$12,736
Denominator for basic net income per share of Class A common stock	'	'	'
Weighted average shares of Class A common stock	32,789	24,086	16,567
Add dilutive effect of the following:	'	'	'
Stock options	616	0	0
Lucid contingently issuable shares	552	0	0
Convertible note hedges	0	0	0
Warrants	0	0	0
Assumed conversion of Holding Units for Class A common stock	0	0	0
Dilutive weighted average shares of Class A common stock	'	24,086	16,567
Basic income per share of Class A common stock (in dollars per share)	$0.45	$0.37	$0.77
Diluted income per share of Class A common stock (in dollars per share)	$0.44	$0.37	$0.77

Amounts_Receivable_From_And_Pa

Amounts Receivable From, And Payable To, Related Parties (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Receivables	'	'
Advances to partners	$0.90	$0
Advances to employees	0.8	0.9
Total	1.7	0.9
Payables	'	'
Guaranty agreements	'	9
Employees	0.7	0.3
Shareholders with greater than 5% ownership in the Company	0.2	0.7
Tax receivable agreement	150.3	100.8
Follow-on Payment	3.7	0
Total	183.1	143.3
Holdings non-controlling units	'	'
Payables	'	'
Due to other related parties	9.8	0
Lucid non controlling units - trade settlements	'	'
Payables	'	'
Due to other related parties	0.2	9.6
Lucid non controlling units - acquisition	'	'
Payables	'	'
Due to other related parties	$9.80	$22.90

Related_Partly_Transaction_Add

Related Partly Transaction - Additional Information (Detail) (USD $)

12 Months Ended

1 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

1 Months Ended

Share data in Thousands, unless otherwise specified

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Mar. 31, 2012

Mar. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Jan. 31, 2014

Common Class A

Common Class A

ODL Group Limited

ODL Group Limited

ODL Group Limited

Global Finance and Master Capital

Global Finance and Master Capital

Global Finance and Master Capital

Shareholders With a Greater Than 5% Ownership

Shareholders With a Greater Than 5% Ownership

Shareholder

Method Credit Fund

Method Credit Fund

Method Credit Fund

Monetary Credit Group LLC

Monetary Credit Group LLC

Monetary Credit Group LLC

Other Income

Other Income

Global Finance and Master Capital

Cash and Cash Equivalents Held for Customers

Cash and Cash Equivalents Held for Customers

Cash and Cash Equivalents Held for Customers

Subsequent Event

Related Party Transaction [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of equity interest

'

'

'

'

'

'

'

'

'

'

'

5.00%

5.00%

'

'

'

'

'

'

'

Percentage of ownership interests

'

'

'

'

'

'

'

'

'

'

'

'

'

90.00%

'

'

'

'

'

'

Referring broker fees

$84,231,000

$76,585,000

$92,832,000

'

'

'

'

'

$1,600,000

$2,500,000

$3,500,000

'

'

'

'

'

'

'

'

'

Settlement agreement, cash paid

'

'

'

'

'

1,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Equity amount issued related to acquisition

'

21,491,000

'

'

'

4,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Forgiveness of liability related to acquisition

'

'

'

'

'

1,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Gain from settlement related to acquisition

'

'

'

'

'

'

1,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Loss related to settlement

'

'

'

'

'

'

'

200,000

'

'

'

'

'

'

'

'

'

'

'

'

Cash collateral amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0

9,000,000

'

8,400,000

6,000,000

Return of cash collateral to former member of Method

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2,400,000

Unconditional guaranty

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,100,000

'

4,500,000

'

'

Proceeds from related parties

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0

0

'

0

'

'

Follow-on Payment

3,700,000

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Exchange of Holdings units into Class A common stock

'

'

'

10,094

10,800

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Conversion ratio

'

'

'

1

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Tax receivable agreement

150,300,000

100,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Payments for tax receivable agreement

$3,800,000

$0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Stock options granted to purchase shares (in shares)	531,636	'	'
Weighted average grant date fair value of stock options granted during the period (in dollars per share)	$5.67	$3.55	$4.26
Unrecognized expense	$12,900,000	'	'
Vested stock options	6,308,628	2,046,250	'
Fair value of vested stock options	32,400,000	21,300,000	'
Cash received from exercise of stock options	22,500,000	'	'
Tax benefit from stock option exercise	1,500,000	'	'
Office, Communication and Computer Equipment, Net [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Capitalized compensation cost	1,400,000	1,400,000	1,100,000
Common Class A	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Other equity awards granted during the period (in shares)	0	945,847	'
Fair value of other equity awards granted during the period (in dollars per share)	'	$11.76	'
Employee Stock Option	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Stock options contractual term	'7 years	'	'
Vesting period	'4 years	'	'
Weighted average grant date fair value of stock options granted during the period (in dollars per share)	$6.02	$3.47	$4.26
Recognition period	'1 year 7 months 15 days	'	'
Employee Stock Option | Compensation and Benefits	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Stock based compensation expense	10,400,000	9,800,000	9,100,000
Employee Stock Option | Common Class A	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Stock options granted to purchase shares (in shares)	426,000	725,000	'
Independent Directors Option	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Stock options contractual term	'7 years	'	'
Weighted average grant date fair value of stock options granted during the period (in dollars per share)	$4.26	$4.11	'
Independent Directors Option | Compensation and Benefits	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Stock based compensation expense	400,000	400,000	400,000
Independent Directors Option | Common Class A	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Stock options granted to purchase shares (in shares)	105,636	109,488	'
Other Equity Awards | Compensation and Benefits	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Stock based compensation expense	$0	$11,100,000	'

Summary_of_Companys_Stock_Opti

Summary of Company's Stock Options Activity Under LTIP (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Number of Stock Options	'	'
Outstanding at January 1, 2013 (in shares)	9,178,128	'
Granted (in shares)	531,636	'
Exercised (in shares)	-1,702,714	'
Forfeited or expired (in shares)	-399,250	'
Outstanding at December 31, 2013 (in shares)	7,607,800	9,178,128
Vested or expected to vest at end of (in shares) period	7,485,369	'
Exercisable as of end period (in shares)	4,445,164	'
Stock options outstanding weighted-average exercise price	'	'
Outstanding at January 1, 2013 (in dollars per share)	$13.37	'
Granted (in dollars per share)	$14.87	'
Exercised (in dollars per share)	$13.21	'
Forfeited or expired (in dollars per share)	$13.78	'
Outstanding at December 31, 2013 (in dollars per share)	$13.48	$13.37
Vested or expected to vest at end of period (in dollars per share)	$13.49	'
Exercisable as of end period (in dollars per share)	$13.77	'
Stock options outstanding weighted-average remaining contractual term	'	'
Outstanding as beginning period	'4 years 3 months 18 days	'2 years 1 month 6 days
Vested or expected to vest at end period	'4 years 3 months 18 days	'
Exercisable as end period	'4 years	'

Assumptions_used_in_Black_Scho

Assumptions used in Black Scholes valuation model (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Assumptions used to Determine Fair Value Options [Line Items]	'	'	'
Estimated fair value at grant date	$5.67	$3.55	$4.26
Employee Stock Option	'	'	'
Assumptions used to Determine Fair Value Options [Line Items]	'	'	'
Expected term in years	'4 years 9 months	'4 years 9 months	'4 years 9 months
Risk-free interest rate	1.06%	0.71%	0.96%
Expected volatility	51.00%	52.00%	56.00%
Dividend yield	1.55%	2.48%	2.24%
Estimated fair value at grant date	$6.02	$3.47	$4.26
Independent Directors	'	'	'
Assumptions used to Determine Fair Value Options [Line Items]	'	'	'
Expected term in years	'4 years	'4 years	'
Risk-free interest rate	0.63%	0.60%	'
Expected volatility	54.00%	63.00%	'
Dividend yield	2.05%	2.40%	'
Estimated fair value at grant date	$4.26	$4.11	'

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)	0 Months Ended			12 Months Ended
	Nov. 07, 2012	Oct. 17, 2011	17-May-11	Dec. 31, 2013	Dec. 31, 2012
				vote
Stockholders Equity Note [Line Items]	'	'	'	'	'
Preferred stock, shares authorized	'	'	'	300,000,000	'
Preferred stock, par value	'	'	'	$0.01	'
Common Class A	'	'	'	'	'
Stockholders Equity Note [Line Items]	'	'	'	'	'
Common stock, shares authorized	'	'	'	3,000,000,000	3,000,000,000
Common stock, par value	'	'	'	$0.01	$0.01
Stock repurchase under stock repurchase program	$80,000,000	$20,000,000	$30,000,000	'	'
Additional stock repurchase under stock repurchase program	30,000,000	'	'	'	'
Stock repurchased and retired	'	'	'	1,815,800	'
Stock repurchase price	'	'	'	$15.46	'
Stock repurchased and retired, value	'	'	'	$28,100,000	'
Class B common stock issued	'	'	'	44,664,884	34,683,599
Common stock votes per share	'	'	'	1	'
Common Class B	'	'	'	'	'
Stockholders Equity Note [Line Items]	'	'	'	'	'
Common stock, shares authorized	'	'	'	1,000,000	1,000,000
Common stock, par value	'	'	'	$0.01	$0.01
Class B common stock issued	'	'	'	41	43
Common stock votes per share	'	'	'	1	'

Changes_in_Companys_Class_A_Co

Changes in Company's Class A Common Stock Shares Outstanding (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Stockholders' Equity Note [Roll Forward]	'	'
Class A Common Stock	1,702,714	'
Common Class A	'	'
Stockholders' Equity Note [Roll Forward]	'	'
Balance at January 1, 2013	34,683,599	'
Issued	0	'
Repurchased	-1,816,000	'
Exchange of Holdings units into Class A common stock	10,094,000	10,800,000
Class A Common Stock	1,702,714	'
Balance at December 31, 2013	44,664,884	34,683,599

Employee_Benefit_Plan_Addition

Employee Benefit Plan - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Compensation and Retirement Disclosure [Abstract]	'	'	'
401K plan contribution	$0	$0	$0

Minimum_Capital_Requirement_An

Minimum Capital Requirement And Excess Capital (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
United States	'	'
Capital Requirements on Foreign Financial Institutions [Line Items]	'	'
Capital	$64.20	$53.50
Minimum capital requirement	27.1	26.1
Excess capital	37.1	27.4
HK	'	'
Capital Requirements on Foreign Financial Institutions [Line Items]	'	'
Capital	33.6	22.7
Minimum capital requirement	12.3	8.1
Excess capital	21.3	14.6
United Kingdom	'	'
Capital Requirements on Foreign Financial Institutions [Line Items]	'	'
Capital	86	73.1
Minimum capital requirement	24.7	17.4
Excess capital	61.3	55.7
Australia	'	'
Capital Requirements on Foreign Financial Institutions [Line Items]	'	'
Capital	4.7	4.2
Minimum capital requirement	0.4	1.2
Excess capital	4.3	3
ODL	'	'
Capital Requirements on Foreign Financial Institutions [Line Items]	'	'
Capital	18.4	14.1
Minimum capital requirement	6.9	4.4
Excess capital	11.5	9.7
FSL	'	'
Capital Requirements on Foreign Financial Institutions [Line Items]	'	'
Capital	34.8	30.7
Minimum capital requirement	8.2	4.4
Excess capital	26.6	26.3
FXCMJ	'	'
Capital Requirements on Foreign Financial Institutions [Line Items]	'	'
Capital	36.3	33.5
Minimum capital requirement	5.6	5.6
Excess capital	30.7	27.9
Lucid LLP	'	'
Capital Requirements on Foreign Financial Institutions [Line Items]	'	'
Capital	41.8	'
Minimum capital requirement	4.2	'
Excess capital	37.6	'
Faros	'	'
Capital Requirements on Foreign Financial Institutions [Line Items]	'	'
Capital	0.1	'
Minimum capital requirement	0	'
Excess capital	$0.10	'

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Commitments and Contingencies Disclosure [Line Items]	'	'	'
Operating lease rental expense	$8.30	$7.90	$8.90
Sublease rentals	'	'	'
Variable Interest Entity, Primary Beneficiary	'	'	'
Commitments and Contingencies Disclosure [Line Items]	'	'	'
Variable Interest Entity, Change in Control, Put Option Buyout Value	$3.30	'	'
Variable Interest Entity, Change in Control, Put Option Buyout, Accretion Interest Rate	15.00%	'	'
Minimum	'	'	'
Commitments and Contingencies Disclosure [Line Items]	'	'	'
Lease renewal options	'3 years	'	'
Maximum	'	'	'
Commitments and Contingencies Disclosure [Line Items]	'	'	'
Lease renewal options	'5 years	'	'

Future_Minimum_Lease_Payments_

Future Minimum Lease Payments Under Noncancelable Operating Leases (Detail) (USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]	'
2014	$7,186
2015	5,847
2016	4,685
2017	3,807
2018	3,612
Thereafter	23,240
Total	$48,377

Debt_Additional_Information_De

Debt - Additional Information (Detail) (USD $)

0 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

Dec. 21, 2013

Dec. 21, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Jun. 18, 2012

Dec. 31, 2013

Jun. 30, 2013

Dec. 31, 2013

Jun. 30, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 21, 2013

Dec. 31, 2013

Dec. 21, 2012

Dec. 31, 2013

Dec. 21, 2012

Dec. 31, 2013

Jun. 18, 2012

Dec. 19, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Nov. 15, 2013

Nov. 08, 2012

Dec. 31, 2013

Dec. 31, 2013

Lucid Markets Trading Limited

Lucid Markets Trading Limited

Lucid Markets Trading Limited

Convertible Debt

Convertible Debt

Convertible Debt

Convertible Debt

Unsecured Promissory Note

Unsecured Promissory Note

Unsecured Promissory Note

Unsecured Promissory Note

Unsecured Promissory Note

Unsecured Promissory Note, One

Unsecured Promissory Note, One

Revolving Credit Facility

Revolving Credit Facility

Revolving Credit Facility

Revolving Credit Facility

Revolving Credit Facility

Revolving Credit Facility

Revolving Credit Facility

Revolving Credit Facility

Restatement Adjustment

2.25% Senior Convertible Notes

2.25% Senior Convertible Notes

2.25% Senior Convertible Notes

Lucid Markets Trading Limited

Lucid Markets Trading Limited

Federal Funds Rate

Eurodollar

D

Interest on Borrowings

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Term

'

'

'

'

'

'

'

'

'

'

'

'

'6 months

'

'

'6 months

'

'

'

'3 years

'

'

'

'

'

'

'

Revolving credit facility borrowing capacity

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$22,900,000

'

'

'

'

$75,000,000

'

'

'

$205,000,000

$155,000,000

'

'

Percentage of equity interests

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

65.00%

'

'

'

'

'

'

'

Revolving credit facility total borrowing capacity

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

250,000,000

175,000,000

'

'

Amount outstanding

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0

85,000,000

'

'

'

'

'

Interest rate

'

2.25%

'

'

'

'

'

'

'

2.25%

'

'

2.25%

2.25%

'

2.25%

3.50%

'

'

'

'

'

'

'

'

0.50%

1.00%

Interest expense, borrowings

'

'

7,673,000

2,763,000

0

'

'

'

2,232,000

'

'

'

'

'

'

'

'

'

'

'

1,400,000

1,200,000

0

'

'

'

'

Debt Instrument, Covenant, Net Capital Required Ratio

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

125.00%

'

'

'

'

'

'

'

'

'

Interest Coverage Ratio

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

4

'

'

'

'

'

'

'

'

'

Consolidated Net Leverage Ratio

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2

'

'

'

'

'

'

'

'

'

Net Unhedged Exposure

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

20.00%

'

'

'

'

'

'

'

'

'

Net Unhedged Non Foreign Currency Exposure

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

10.00%

'

'

'

'

'

'

'

'

'

Weighted average dollar amount of borrowings related to the credit agreement

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

34,900,000

41,200,000

41,200,000

'

'

'

'

Debt, weighted average interest rate

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2.40%

2.10%

2.10%

'

'

'

'

Face amount

'

'

'

'

'

'

'

'

'

172,500,000

'

'

'

'

'

'

'

'

71,400,000

'

'

'

'

'

15,800,000

'

'

Proceeds from issuance of senior convertibles notes, net

'

'

166,453,000

0

0

'

'

'

'

166,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Conversion ratio

'

'

'

'

'

'

'

'

'

53.2992

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Conversion price (in dollars per share)

'

'

'

'

'

'

'

'

'

$18.76

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Threshold trading days

'

'

'

'

'

'

'

'

'

20

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Threshold consecutive trading days

'

'

'

'

'

'

'

'

'

'30 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Threshold percentage of stock price trigger

'

'

'

'

'

'

'

'

'

130.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Measurement period, business days

'

'

'

'

'

'

'

'

'

5

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Measurement period, trading days

'

'

'

'

'

'

'

'

'

5

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Measurement period threshold percentage

'

'

'

'

'

'

'

'

'

98.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Repurchase percentage under certain conditions

'

'

'

'

'

'

'

'

'

100.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Warrant strike price

'

'

$21.24

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cost of convertible note hedge

'

'

29,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Proceeds from sale of warrants

'

'

18,571,000

0

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Equity component

'

'

'

'

'

'

'

'

29,101,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Liability component - net carrying value

'

'

'

'

'

'

'

'

146,303,000

144,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Effective interest rate

'

'

'

'

'

'

'

'

'

6.20%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Issuance costs

'

'

'

'

'

'

'

'

'

6,000,000

5,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt issuance cost

'

'

'

'

'

'

'

'

'

'

'

700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument maturity date

'

'

'

'

'

'

'

'

'

'

'

'

21-Dec-12

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Purchase price

'

'

'

'

'

177,500,000

192,784,000

[1]

15,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Repayments of Notes Payable

5,500,000

64,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Notes payable

'

'

'

'

'

'

$9,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

[1]

The amounts included in the Lucid Purchase Price Allocation table represent the allocation of the purchase price and includes revisions made during the 12 months remeasurement period from the Acquisition Date.

Applicable_Margin_and_Commitme

Applicable Margin and Commitment Fees (Detail) (Revolving Credit Facility)	12 Months Ended
	Dec. 31, 2013
Less than .50 to 1.00	'
Debt Instrument [Line Items]	'
Commitment Fee	0.25%
Less than .50 to 1.00 | Maximum	'
Debt Instrument [Line Items]	'
Consolidated leverage ratio	0.5
Less than .50 to 1.00 | Eurodollar	'
Debt Instrument [Line Items]	'
Applicable rate for variable rate	1.75%
Less than .50 to 1.00 | Base Rate	'
Debt Instrument [Line Items]	'
Applicable rate for variable rate	0.75%
Greater than or equal to 0.50 to 1.00 but less than 1.00 to 1.00	'
Debt Instrument [Line Items]	'
Commitment Fee	0.30%
Greater than or equal to 0.50 to 1.00 but less than 1.00 to 1.00 | Minimum	'
Debt Instrument [Line Items]	'
Consolidated leverage ratio	0.5
Greater than or equal to 0.50 to 1.00 but less than 1.00 to 1.00 | Maximum	'
Debt Instrument [Line Items]	'
Consolidated leverage ratio	1
Greater than or equal to 0.50 to 1.00 but less than 1.00 to 1.00 | Eurodollar	'
Debt Instrument [Line Items]	'
Applicable rate for variable rate	2.00%
Greater than or equal to 0.50 to 1.00 but less than 1.00 to 1.00 | Base Rate	'
Debt Instrument [Line Items]	'
Applicable rate for variable rate	1.00%
Greater than or equal to 1.00 to 1.00 but less than 1.50 to 1.00	'
Debt Instrument [Line Items]	'
Commitment Fee	0.35%
Greater than or equal to 1.00 to 1.00 but less than 1.50 to 1.00 | Minimum	'
Debt Instrument [Line Items]	'
Consolidated leverage ratio	1
Greater than or equal to 1.00 to 1.00 but less than 1.50 to 1.00 | Maximum	'
Debt Instrument [Line Items]	'
Consolidated leverage ratio	1.5
Greater than or equal to 1.00 to 1.00 but less than 1.50 to 1.00 | Eurodollar	'
Debt Instrument [Line Items]	'
Applicable rate for variable rate	2.25%
Greater than or equal to 1.00 to 1.00 but less than 1.50 to 1.00 | Base Rate	'
Debt Instrument [Line Items]	'
Applicable rate for variable rate	1.25%
Greater than or equal to 1.50 to 1.00, but less than 2.00 to 1.00	'
Debt Instrument [Line Items]	'
Commitment Fee	0.40%
Greater than or equal to 1.50 to 1.00, but less than 2.00 to 1.00 | Minimum	'
Debt Instrument [Line Items]	'
Consolidated leverage ratio	1.5
Greater than or equal to 1.50 to 1.00, but less than 2.00 to 1.00 | Maximum	'
Debt Instrument [Line Items]	'
Consolidated leverage ratio	2
Greater than or equal to 1.50 to 1.00, but less than 2.00 to 1.00 | Eurodollar	'
Debt Instrument [Line Items]	'
Applicable rate for variable rate	2.50%
Greater than or equal to 1.50 to 1.00, but less than 2.00 to 1.00 | Base Rate	'
Debt Instrument [Line Items]	'
Applicable rate for variable rate	1.50%
Greater than or equal to 2.00 to 1.00	'
Debt Instrument [Line Items]	'
Commitment Fee	0.45%
Greater than or equal to 2.00 to 1.00 | Minimum	'
Debt Instrument [Line Items]	'
Consolidated leverage ratio	2
Greater than or equal to 2.00 to 1.00 | Eurodollar	'
Debt Instrument [Line Items]	'
Applicable rate for variable rate	2.75%
Greater than or equal to 2.00 to 1.00 | Base Rate	'
Debt Instrument [Line Items]	'
Applicable rate for variable rate	1.75%

Convertible_Debt_Details

Convertible Debt (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Debt Instrument [Line Items]	'	'	'
Interest expense - stated coupon rate	$7,673,000	$2,763,000	$0
Interest expense - amortization of deferred bond discount	2,904,000	0	0
Interest expense - amortization of debt issuance cost	1,263,000	304,000	0
Convertible Debt	'	'	'
Debt Instrument [Line Items]	'	'	'
Liability component - principal	172,500,000	'	'
Deferred bond discount	-26,197,000	'	'
Liability component - net carrying value	146,303,000	'	'
Equity component	29,101,000	'	'
Interest expense - stated coupon rate	2,232,000	'	'
Interest expense - amortization of deferred bond discount	2,904,000	'	'
Interest expense - amortization of debt issuance cost	699,000	'	'
Total interest expense - Convertible Notes	$5,835,000	'	'

Offsetting_Assets_and_Liabilit

Offsetting Assets and Liabilities (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'	'
Gross fair values	$84	$520
Netting agreements	-84	-265
Net fair values	0	255
Gross fair values	-2,404	-265
Netting agreements	84	265
Net fair values	-2,320	0
Net	-2,320	'
Net	'	$255

Derivative_Financial_Instrumen2

Derivative Financial Instruments - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'	'	'
Total revenue	$489,588,000	$417,315,000	$415,578,000
Trading activity, loss	74,300,000	46,300,000	8,800,000
Derivative, notional amount	$159,900,000	$119,500,000	'

Fair_Value_Measured_on_a_Recur

Fair Value Measured on a Recurring Basis (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Quoted Prices in Active Markets for Identical Assets (Level I)	'	'
Financial Assets:	'	'
Total assets	$5,450	'
Financial Liabilities:	'	'
Total liabilities	6,332	'
Significant Observable Inputs (Level II)	'	'
Financial Assets:	'	'
Total assets	0	'
Financial Liabilities:	'	'
Total liabilities	149,418	'
Significant Unobservable Inputs (Level III)	'	'
Financial Assets:	'	'
Total assets	25,446	'
Financial Liabilities:	'	'
Total liabilities	9,800	'
Fair Value, Measurements, Recurring	'	'
Financial Assets:	'	'
Cash and cash equivalents	365,245	272,332
Cash and cash equivalents, held for customers	1,190,880	1,190,762
Due from brokers- open futures contracts	'	255
Total assets	1,556,125	1,463,349
Financial Liabilities:	'	'
Customer account liabilities	1,190,880	1,190,762
Due to brokers- open futures contracts	2,320	'
Follow-on Payment	3,672	'
Total liabilities	1,196,872	1,190,762
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level I)	'	'
Financial Assets:	'	'
Cash and cash equivalents	365,245	272,332
Cash and cash equivalents, held for customers	1,190,880	1,190,762
Due from brokers- open futures contracts	'	255
Total assets	1,556,125	1,463,349
Financial Liabilities:	'	'
Customer account liabilities	1,190,880	1,190,762
Due to brokers- open futures contracts	2,320	'
Follow-on Payment	0	'
Total liabilities	1,193,200	1,190,762
Fair Value, Measurements, Recurring | Significant Observable Inputs (Level II)	'	'
Financial Assets:	'	'
Cash and cash equivalents	0	0
Cash and cash equivalents, held for customers	0	0
Due from brokers- open futures contracts	'	0
Total assets	0	0
Financial Liabilities:	'	'
Customer account liabilities	0	0
Due to brokers- open futures contracts	0	'
Follow-on Payment	0	'
Total liabilities	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level III)	'	'
Financial Assets:	'	'
Cash and cash equivalents	0	0
Cash and cash equivalents, held for customers	0	0
Due from brokers- open futures contracts	'	0
Total assets	0	0
Financial Liabilities:	'	'
Customer account liabilities	0	0
Due to brokers- open futures contracts	0	'
Follow-on Payment	3,672	'
Total liabilities	$3,672	$0

Fair_Value_by_Balance_Sheet_Gr

Fair Value by Balance Sheet Groupings (Details) (USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Quoted Prices in Active Markets for Identical Assets (Level I)	'
Financial Assets:	'
Due from brokers- unsettled spot FX	$5,450
Equity method investments	0
Notes receivable	0
Total assets	5,450
Financial Liabilities:	'
Due to brokers- unsettled spot FX	6,332
Notes payable	0
Senior convertible notes	0
Total liabilities	6,332
Significant Observable Inputs (Level II)	'
Financial Assets:	'
Due from brokers- unsettled spot FX	0
Equity method investments	0
Notes receivable	0
Total assets	0
Financial Liabilities:	'
Due to brokers- unsettled spot FX	0
Notes payable	0
Senior convertible notes	149,418
Total liabilities	149,418
Significant Unobservable Inputs (Level III)	'
Financial Assets:	'
Due from brokers- unsettled spot FX	0
Equity method investments	13,504
Notes receivable	11,942
Total assets	25,446
Financial Liabilities:	'
Due to brokers- unsettled spot FX	0
Notes payable	9,800
Senior convertible notes	0
Total liabilities	9,800
Carrying Value	'
Financial Assets:	'
Due from brokers- unsettled spot FX	5,450
Equity method investments	9,793
Notes receivable	11,942
Total assets	27,185
Financial Liabilities:	'
Due to brokers- unsettled spot FX	6,332
Notes payable	9,800
Senior convertible notes	146,303
Total liabilities	162,435
Fair Value	'
Financial Assets:	'
Due from brokers- unsettled spot FX	5,450
Equity method investments	13,504
Notes receivable	11,942
Total assets	30,896
Financial Liabilities:	'
Due to brokers- unsettled spot FX	6,332
Notes payable	9,800
Senior convertible notes	149,418
Total liabilities	$165,550

Fair_Value_Measurements_Signif

Fair Value Measurements Significant Unobservable Inputs Reconciliation (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'
Beginning Balance	$0
Additions	10,631
Net Unrealized/Realized (Gains) Losses	-6,959
Total	3,672
Follow-on Payment	'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'
Beginning Balance	0
Additions	10,631
Net Unrealized/Realized (Gains) Losses	-6,959
Total	$3,672
Change in fair value due to 10% in multiple or EBITDA	24.00%

Income_from_continuing_operati

Income from continuing operations before income taxes (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]	'	'	'
Domestic	$10,390	$19,794	$29,035
Foreign	41,470	27,670	40,562
Income before income taxes	$51,860	$47,464	$69,597

Provision_for_income_taxes_con

Provision for income taxes consists (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Current	'	'	'
Federal income tax (benefit)	($185)	$478	$238
State and local income tax	682	574	1,384
Foreign income tax	5,085	764	9,268
Subtotal	5,582	1,816	10,890
Deferred	'	'	'
Federal income tax	3,996	2,837	7,578
State and local income tax (benefit)	235	-171	-1,802
Foreign income tax (benefit)	7,211	4,504	-5,850
Subtotal	11,442	7,170	-74
Total provision for taxes	$17,024	$8,986	$10,816

Reconciles_provision_for_taxes

Reconciles provision for taxes (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]	'	'	'
Statutory U.S. federal income tax rate	34.00%	34.00%	34.00%
Income passed through to non-controlling members	-5.40%	-15.50%	-13.00%
State and local income tax	0.90%	1.00%	2.10%
Foreign income tax	-1.40%	-3.10%	-0.20%
Release of valuation allowance	0.00%	0.00%	-11.80%
Non- deductible FCA fine	2.00%	0.00%	0.00%
Foreign tax credit valuation allowance	3.50%	2.50%	0.80%
Impact of rate change on deferred tax assets	-0.90%	0.00%	4.00%
Other	0.10%	0.00%	-0.40%
Effective tax rate	32.80%	18.90%	15.50%

Tax_effects_of_temporary_diffe

Tax effects of temporary differences (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Deferred tax assets	'	'
Equity based compensation	$1,059	$1,259
Investment in partnership	178,941	118,327
Fixed assets	2,279	4,009
Tax loss carryforwards	25,631	7,761
Tax credit carryforward/foreign sub income	4,265	2,083
Japan software	1,516	3,083
Other	577	140
Gross deferred tax assets	214,268	136,662
Less: valuation allowance	-25,288	-8,843
Net deferred tax asset	188,980	127,819
Deferred tax liabilities	'	'
Fixed assets	4	65
Intangible assets	3,965	6,292
Goodwill	8,742	12,563
Software development cost	238	193
Other	1,232	338
Gross deferred tax liabilities	14,181	19,451
Net deferred tax asset	$174,799	$108,368

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Income Tax Contingency [Line Items]	'	'
Valuation allowance	($25,288,000)	($8,843,000)
Income tax reconciliation tax credits foreign	3,600,000	'
Tax credit carryforward period	'10 years	'
Income tax reconciliation tax credits	400,000	'
Business tax credit carryforward period	'7 years	'
Deferred tax assets not recognized permanent difference	28,100,000	'
Tax receivable	3,861,000	6,003,000
Accounts Payable and Accrued Expenses	'	'
Income Tax Contingency [Line Items]	'	'
Taxes Payable	1,000,000	1,200,000
United Kingdom	'	'
Income Tax Contingency [Line Items]	'	'
Operating loss carry forwards, foreign	$129,800,000	'

Reconciliation_of_Unrecognized

Reconciliation of Unrecognized Tax Benefits (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]	'	'	'
Unrecognized tax benefits – January 1	$3,691	$223	$0
Gross increases – tax positions in prior period	0	1	44
Gross decreases – tax positions in prior period	-3,445	-16	0
Gross increases – tax positions in current period	51	3,483	179
Settlement	-114	0	0
Lapse of statute of limitations	0	0	0
Unrecognized tax benefits – December 31	$183	$3,691	$223

Foreign_Currencies_and_Concent1

Foreign Currencies and Concentrations of Credit Risk - Additional Information (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	bank	bank
Foreign Currency [Abstract]	'	'
Due from brokers	$5,450	$8,040
Percentage of due from correspondent brokers	96.20%	91.50%
Banks held more than 10% each of the company's total cash and cash equivalents	2	3
Percentage of cash and cash equivalent	10.00%	'

Companys_Operations_by_Reporta

Company's Operations by Reportable Segment (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	Segment
Segment Reporting Information [Line Items]	'	'	'
Number of operating segments	2	'	'
Total revenue	$489,588	$417,315	$415,578
Operating and other expenses	437,728	369,851	345,981
Income before income taxes	51,860	47,464	69,597
Assets	2,223,947	2,065,170	1,487,133
Corporate	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Total revenue	-1,209	0	3,314
Operating and other expenses	119,176	106,669	106,663
Income before income taxes	-120,385	-106,669	-103,349
Assets	183,626	127,122	116,022
Operating Segments | Retail Trading	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Total revenue	379,840	355,282	383,356
Operating and other expenses	219,016	218,018	218,534
Income before income taxes	160,824	137,264	164,822
Assets	1,622,829	1,556,680	1,361,577
Operating Segments | Institutional Trading	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Total revenue	110,957	62,033	28,908
Operating and other expenses	99,536	45,164	20,784
Income before income taxes	11,421	16,869	8,124
Assets	$417,492	$381,368	$9,534

Companys_Operations_by_Geograp

Company's Operations by Geographical Reportable Segment (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting, Asset Reconciling Item [Line Items]	'	'	'
Total revenue	$489,588	$417,315	$415,578
Operating and other expenses	437,728	369,851	345,981
Income before income taxes	51,860	47,464	69,597
Eliminations	'	'	'
Segment Reporting, Asset Reconciling Item [Line Items]	'	'	'
Total revenue	-160,556	-114,179	-111,919
Operating and other expenses	-160,556	-112,764	-111,919
Income before income taxes	0	-1,415	0
United States	'	'	'
Segment Reporting, Asset Reconciling Item [Line Items]	'	'	'
Total revenue	301,005	284,511	329,366
Operating and other expenses	290,549	264,706	299,841
Income before income taxes	10,456	19,805	29,525
Asia	'	'	'
Segment Reporting, Asset Reconciling Item [Line Items]	'	'	'
Total revenue	57,557	51,486	27,960
Operating and other expenses	39,410	41,228	24,173
Income before income taxes	18,147	10,258	3,787
Europe Middle East and North Africa	'	'	'
Segment Reporting, Asset Reconciling Item [Line Items]	'	'	'
Total revenue	286,771	191,314	165,073
Operating and other expenses	265,218	173,467	130,254
Income before income taxes	21,553	17,847	34,819
Other	'	'	'
Segment Reporting, Asset Reconciling Item [Line Items]	'	'	'
Total revenue	4,811	4,183	5,098
Operating and other expenses	3,107	3,214	3,632
Income before income taxes	$1,704	$969	$1,466

Litigation_Details

Litigation (Details)	Dec. 31, 2013	Feb. 28, 2014	Oct. 31, 2011	Mar. 31, 2013	Dec. 31, 2012	Jan. 31, 2014	Feb. 28, 2014
	USD ($)	Subsequent Event	United States Bankruptcy Court for the Southern District of Florida	JFSA	JFSA	Texas Securities Act	Restitution to Affected Clients
		Settlement with FCA	USD ($)	USD ($)	USD ($)	Subsequent Event	Subsequent Event
		GBP (£)	debtor			Minimum	Maximum
						USD ($)	Settlement with FCA
							USD ($)
Loss Contingencies [Line Items]	'	'	'	'	'	'	'
Number of debtors	'	'	3	'	'	'	'
Settlement	'	£ 4,000,000	$700,000	$2,300,000	'	'	$9,900,000
Accrual	'	'	'	'	2,600,000	'	'
Damages claimed	'	'	'	'	'	3,800,000	'
Range of loss, minimum	0	'	'	'	'	'	'
Range of loss, maximum	$3,800,000	'	'	'	'	'	'

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (Subsequent Event, USD $)	Mar. 14, 2014	Mar. 14, 2014	Feb. 28, 2014
		Common Class A	Infinium Capital
Subsequent Event [Line Items]	'	'	'
Purchase price	'	'	$30,000,000
Liabilities incurred	'	'	11,900,000
Acquisition of controlling interest	'	'	50.10%
Amount outstanding	$50,000,000	'	'
Dividend declared (in dollars per share)	'	$0.06	'