Debt Instrument, Covenants, Ratio of Principal Indebtedness to Net Worth to Trigger Default

No definition available.

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- 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

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

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

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.

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- Definition

Amount, after accumulated amortization, of debt discount.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28541-108399

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

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- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ 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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ 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 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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

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

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Notes Payable - Existing Credit Agreement (Details) - USD ($)				3 Months Ended	12 Months Ended
	Nov. 17, 2017	Apr. 27, 2017	Jun. 25, 2013	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Notes payable				$ 748,000,000	$ 759,000,000	$ 987,000,000
Line of Credit \| Minimum
Debt Instrument [Line Items]
Stated interest rate (as percent)			1.10%
Line of Credit \| Maximum
Debt Instrument [Line Items]
Stated interest rate (as percent)			1.60%
Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility	$ 100,000,000
Extended term (in years)	5 years
Revolving Credit Facility \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as percent)	4.50%
Revolving Credit Facility \| Line of Credit \| Revolving Credit Facility due July 2018
Debt Instrument [Line Items]
Line of credit facility			$ 800,000,000
Ratio of principal indebtedness to net worth to trigger default			3.00%
Notes payable					295,000,000	(3,000,000)
Unamortized debt issue costs					(5,000,000)
Unused portion					500,000,000	$ 500,000,000
Revolving Credit Facility \| Line of Credit \| Revolving Credit Facility due July 2018 \| Minimum
Debt Instrument [Line Items]
Commitment fee percentage			0.15%
Revolving Credit Facility \| Line of Credit \| Revolving Credit Facility due July 2018 \| Maximum
Debt Instrument [Line Items]
Commitment fee percentage			0.40%
Revolving Credit Facility \| Line of Credit \| Revolving Credit Facility due July 2018 \| Federal Funds Rate
Debt Instrument [Line Items]
Basis spread on variable rate (as percent)			0.50%
Revolving Credit Facility \| Line of Credit \| Revolving Credit Facility due July 2018 \| One Month London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate (as percent)			1.00%
Revolving Credit Facility \| Line of Credit \| Revolving Credit Facility due July 2018 \| Base Rate \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (as percent)			0.10%
Revolving Credit Facility \| Line of Credit \| Revolving Credit Facility due July 2018 \| Base Rate \| Maximum
Debt Instrument [Line Items]
Basis spread on variable rate (as percent)			0.60%
Revolving Credit Facility \| Line of Credit \| Revolving Credit Facility due July 2018 \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as percent)			1.40%
Revolving Credit Facility \| Line of Credit \| Revolving Credit Facility Due April 2022
Debt Instrument [Line Items]
Line of credit facility			$ 800,000,000
Extended term (in years)		5 years
Notes payable				295,000,000	$ 295,000,000
Unamortized debt issue costs				(5,000,000)
Unused portion				$ 500,000,000
Revolving Credit Facility \| Line of Credit \| Revolving Credit Facility Due April 2022 \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as percent)				1.40%	1.40%