Equity Method Investment, Percentage of Voting Interest Held

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- Definition

Amount of direct costs of the business combination including legal, accounting, and other costs incurred to consummate the business acquisition.

+ References

No definition available.

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

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- Definition

Amount after accretion (amortization) of discount (premium), and investment expense, of interest income and dividend income on nonoperating securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.8)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.7(a),(b))

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.9)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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- Definition

The cash inflow from other equity not otherwise defined in the taxonomy.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3255-108585

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Investments - Additional Information (Details) (USD $)	12 Months Ended			3 Months Ended
Investments - Additional Information (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2014	Sep. 30, 2014
Schedule of Equity Method Investments [Line Items]
Proceeds and distributions from investments	$ 58,660,000us-gaap_ProceedsFromOtherEquity	$ 3,251,000us-gaap_ProceedsFromOtherEquity	$ 72,196,000us-gaap_ProceedsFromOtherEquity
Investment income and other, net	41,232,000us-gaap_InvestmentIncomeNet	124,095,000us-gaap_InvestmentIncomeNet	27,010,000us-gaap_InvestmentIncomeNet
BATS [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of equity in common stock of private companies cover under strategic investment	16.70%
Percentage of voting interest held	19.90%
BATS and DE [Member]
Schedule of Equity Method Investments [Line Items]
Proceeds and distributions from investments	42,200,000
Merger related transaction costs				6,600,000
BATS and DE [Member] \| Investment Income and Other, Net [Member]
Schedule of Equity Method Investments [Line Items]
Investment income and other, net				9,600,000
DE [Member]
Schedule of Equity Method Investments [Line Items]
Investment income and other, net				16,200,000
tradeMonster [Member] \| Investment Income and Other, Net [Member]
Schedule of Equity Method Investments [Line Items]
Investment income and other, net					15,100,000
TM Holdings [Member]
Schedule of Equity Method Investments [Line Items]
Investment income and other, net					$ 17,600,000