Class of Warrant or Right, Repurchases During Period, Shares

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- Definition

Class of Warrant or Right, Repurchases During Period, Value

+ References

No definition available.

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- Definition

Disposal Group, Sale Period

+ References

No definition available.

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- Definition

Proceeds from Divestiture of Business Related to Tax Benefits

+ References

No definition available.

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- Definition

Related Party Transaction, Number of Beneficial Owners

+ References

No definition available.

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- Definition

Stock Repurchase Program, Fees

+ References

No definition available.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

For an unclassified balance sheet, the amount as of the balance sheet date of capitalized costs associated with the issuance of debt instruments (for example, legal, accounting, underwriting, printing, and registration costs) that will be charged against earnings over the life of the debt instruments to which such costs pertain. Such amount is before the consideration of accumulated amortization.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28555-108399

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- Definition

Amount of consideration received or receivable for the disposal of assets and liabilities, including discontinued operation.

+ References

No definition available.

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- Definition

Amount of gain (loss) on sale or disposal of an equity method investment.

+ References

No definition available.

+ Details

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- Definition

Gain (loss) from sale or disposal of an organization or integrated set of activities (for example, but not limited to, a partnership or corporation) engaged in providing a product or service in a commercial, industrial, or professional environment.

+ References

No definition available.

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- Definition

Amount of fees earned from providing investment advice and research to customers.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.13(a),(d))
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

+ Details

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- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

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- Definition

The cash inflow associated with the sale of other investments not otherwise defined in the taxonomy.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3179-108585

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3521-108585

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-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 26
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3574-108585

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- Definition

A fee charged for services from professionals such as doctors, lawyers and accountants. The term is often expanded to include other professions, for example, pharmacists charging to maintain a medicinal profile of a client or customer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07.2(a),(b),(c),(d))
-URI http://asc.fasb.org/extlink&oid=6488393&loc=d3e606610-122999

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 225
-Section 45
-Paragraph 3
-Subparagraph (k)
-URI http://asc.fasb.org/extlink&oid=6488370&loc=d3e13550-115849

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

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Balance Type:	na
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- Definition

Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29, 30
-Article 5

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- Definition

Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29, 30, 31
-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

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- Definition

The charge against earnings resulting from the aggregate write down of tangible assets from their carrying value to their fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=51719941&loc=d3e2921-110230

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=51717284&loc=d3e1361-107760

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Related Parties - Additional Information (Details) $ / shares in Units, shares in Thousands, $ in Thousands				1 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended
	Dec. 29, 2015 USD ($)	Nov. 11, 2015 USD ($) shares	Nov. 04, 2015 USD ($) $ / shares shares	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($) beneficial_owner shares	Dec. 31, 2013 USD ($)	Dec. 31, 2015 USD ($) beneficial_owner shares	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Jun. 02, 2015 $ / shares	Mar. 10, 2015
Related Party Transaction [Line Items]
Professional fees							$ 27,055	$ 25,596	$ 46,662
Repurchased amount						$ 11,324	$ 63,194	111,585
Warrants repurchased (in shares) \| shares					2,600		2,578
Warrants repurchased					$ 4,400
Aperture
Related Party Transaction [Line Items]
Aggregate purchase price	$ 28,500
Tender Offer
Related Party Transaction [Line Items]
Professional fees							$ 2,100
Investment Income and Other, Net \| Aperture
Related Party Transaction [Line Items]
Gain from sale of investment	$ 10,500						10,500
KCG Hotspot
Related Party Transaction [Line Items]
Gain from sale of business							373,800
Proceeds related to tax sharing arrangement				$ 70,000			$ 70,000
Sale period				3 years			3 years
Additional consideration, fair value					64,200		$ 64,200
KCG Hotspot \| Other Assets
Related Party Transaction [Line Items]
Additional consideration, fair value					$ 64,200		64,200
KCG Hotspot \| Investment Income and Other, Net
Related Party Transaction [Line Items]
Gain from sale of business							385,000
KCG Hotspot \| Professional Fees
Related Party Transaction [Line Items]
Professional fees							$ 6,700
Senior Secured Notes \| 6.875% Senior Secured Notes
Related Party Transaction [Line Items]
Interest rate					6.875%		6.875%				6.875%
Senior Secured Notes \| 6.875% Senior Secured Notes \| Other Assets
Related Party Transaction [Line Items]
Deferred debt costs					$ 12,600		$ 12,600
Common Class A
Related Party Transaction [Line Items]
Repurchased shares \| shares							3,500
Repurchased amount							$ 41,700
Common Class A \| Tender Offer
Related Party Transaction [Line Items]
Shares repurchased, price per share (in usd per share) \| $ / shares										$ 14.00
Related Parties
Related Party Transaction [Line Items]
Financing and advisory fees							16,800
Professional fees							5,507	$ 0	$ 0
Related Parties \| Other Assets
Related Party Transaction [Line Items]
Deferred debt costs					$ 11,300		11,300
Related Parties \| Treasury Stock
Related Party Transaction [Line Items]
Stock buyback program fees							31
Related Parties \| Professional Fees
Related Party Transaction [Line Items]
Professional fees							$ 5,500
Related Parties \| Common Class A
Related Party Transaction [Line Items]
Number of beneficial owners \| beneficial_owner					1		1
Noncontrolling interest, ownership percentage by noncontrolling owners (more than)					10.00%		10.00%
JV \| Write-down of Assets and Other Real Estate Charges
Related Party Transaction [Line Items]
Writedown of assets to fair value					$ 4,300		$ 4,300
Serenity
Related Party Transaction [Line Items]
Repurchased amount			$ 24,500
Serenity \| Common Class A
Related Party Transaction [Line Items]
Shares repurchased, price per share (in usd per share) \| $ / shares			$ 12.89
Repurchased shares \| shares			1,900
Daniel Tierney
Related Party Transaction [Line Items]
Warrants repurchased (in shares) \| shares		2,000
Warrants repurchased		$ 3,600