Debt instrument interest additional interest above eurodollar rate.

No definition available.

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- Definition

Debt instrument interest additional interest above federal fund rate.

+ References

No definition available.

+ Details

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- Definition

Debt Instrument, Number of Debt Agreement Amendments

+ References

No definition available.

+ Details

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- Definition

Line of credit facility, additional borrowing capacity.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line of Credit Facility, Frequency of Payments, Number of Quarterly Installments

+ References

No definition available.

+ Details

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- Definition

Maximum applicable margin rate.

+ References

No definition available.

+ Details

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- Definition

Minimum applicable margin rate.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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Balance Type:	credit
Period Type:	instant

- 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.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3255-108585

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Debt - 2016 Credit Agreement (Details)			12 Months Ended
Debt - 2016 Credit Agreement (Details)	Apr. 05, 2017 USD ($) installment amendment	Mar. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016	Dec. 31, 2018 USD ($)
Debt Instrument [Line Items]
Long-term debt, gross			$ 3,323,062,000		$ 2,312,092,000
Federal Funds rate
Debt Instrument [Line Items]
Additional interest above federal fund rate				0.50%
2016 Credit Facility Agreement
Debt Instrument [Line Items]
Number of debt agreement amendments \| amendment	3
Debt instrument, interest, additional interest above eurodollar rate	1.00%
2016 Credit Facility Agreement \| Federal Funds rate
Debt Instrument [Line Items]
Minimum applicable margin rate	0.125%
Maximum applicable margin rate	1.50%
2016 Credit Facility Agreement \| Euro Dollar rate
Debt Instrument [Line Items]
Minimum applicable margin rate	1.125%
Maximum applicable margin rate	2.50%
Term loan
Debt Instrument [Line Items]
Long-term debt, gross			1,429,312,000		1,355,062,000
Term B facility
Debt Instrument [Line Items]
Long-term debt, gross			496,250,000		0
Senior notes
Debt Instrument [Line Items]
Proceeds from issuance of debt		$ 800,000,000
Long-term debt, gross			800,000,000		800,000,000
Secured Debt \| 2016 Credit Facility Agreement
Debt Instrument [Line Items]
Line of credit facility, frequency of payments in quarterly installments \| installment	16
Secured Debt \| Term loan \| 2016 Credit Facility Agreement
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			1,500,000,000
Revolving Credit Facility
Debt Instrument [Line Items]
Long-term debt, gross			595,000,000		$ 155,000,000
Revolving Credit Facility \| 2016 Credit Facility Agreement
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			1,200,000,000
CEB
Debt Instrument [Line Items]
Proceeds from issuance of debt	$ 2,800,000,000
CEB \| 2016 Credit Facility Agreement
Debt Instrument [Line Items]
Proceeds from issuance of debt	$ 1,675,000,000
CEB \| Senior notes
Debt Instrument [Line Items]
Proceeds from issuance of debt		$ 800,000,000
CEB \| Secured Debt \| Term B facility \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	2.00%
CEB \| Secured Debt \| Term B facility \| Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
CEB \| Secured Debt \| Term loan \| 2016 Credit Facility Agreement
Debt Instrument [Line Items]
Additional borrowing capacity	$ 900,000,000
CEB \| Secured Debt \| Term B facility \| 2016 Credit Facility Agreement
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 500,000,000
Proceeds from issuance of debt	500,000,000
CEB \| Revolving Credit Facility
Debt Instrument [Line Items]
Proceeds from issuance of debt	275,000,000
Bridge Loan \| CEB
Debt Instrument [Line Items]
Proceeds from issuance of debt	$ 300,000,000
Debt instrument term	364 days		364 days