Refers to the period of unsecured term loan facility.

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

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

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- Definition

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

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-Paragraph 12

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Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

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- Details

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- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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

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-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(2))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
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- Definition

Amount borrowed under the credit facility as of the balance sheet date.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

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- Definition

Average amount borrowed under the credit facility during the period.

+ References

No definition available.

+ Details

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- Definition

Amount of the fee for available but unused credit capacity under the credit 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))

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-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

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Balance Type:	debit
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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

Amount of long-term debt, after unamortized discount or premium, scheduled to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19,20)

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-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19

-Article 5

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- Definition

The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

+ 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

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-Topic 230

-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (b)

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

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- Definition

Carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion. Senior note holders are paid off in full before any payments are made to junior note holders.

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

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- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

+ References

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-Topic 942

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-Subparagraph (SX 210.9-03.16)

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-Section S99

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

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Long-Term Debt, Narrative (Details) (USD $)	12 Months Ended
Long-Term Debt, Narrative (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Senior Notes	$ 500,000,000us-gaap_SeniorNotes
Additional notes issued	0	225,000,000	275,000,000
Current portion of long-term debt	116,700,000us-gaap_LongTermDebtCurrent	0us-gaap_LongTermDebtCurrent
Total debt outstanding, Fair value	705,215,000us-gaap_DebtInstrumentFairValue	710,377,000us-gaap_DebtInstrumentFairValue
Commitment fee (in hundredths)	0.30%
Senior Notes Series A Due February 27, 2020 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage (in hundredths)	2.72%
Additional notes issued	67,500,000
Credit facility, amount outstanding	150,000,000	150,000,000
Senior debt retired	82,500,000
Senior Notes Series B Due February 27, 2023 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage (in hundredths)	3.29%
Additional notes issued	157,500,000
Credit facility, amount outstanding	350,000,000	350,000,000
Senior debt retired	192,500,000
Term Loan Due July 1, 2016 [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	100,000,000	208,000,000
Revolving Credit Facility Due November 9, 2015 [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	116,700,000	41,150,000
Term Loan [Member]
Debt Instrument [Line Items]
Maturity date	Jul. 01, 2016
Average borrowing under revolving credit facility	152,892,000
Senior debt retired	100,000,000
Current portion of long-term debt	0
Term loan, duration	5 years
Weighted average interest rate (in hundredths)	1.70%
Term Loan [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Interest rate, variable rate basis	LIBOR
Basis spread on variable rate (in hundredths)	1.50%
Term Loan [Member] \| Alternate Base Rate [Member]
Debt Instrument [Line Items]
Interest rate, variable rate basis	Alternate Base Rate
Basis spread on variable rate (in hundredths)	0.50%
Senior Notes [Member]
Debt Instrument [Line Items]
Senior debt retired			200,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maturity date	Nov. 09, 2015
Average borrowing under revolving credit facility	28,591,000
Commitment amount	25,000,000
Credit facility, amount outstanding	4,939,000
Weighted average interest rate (in hundredths)	1.70%
Revolving Credit Facility [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Interest rate, variable rate basis	LIBOR
Basis spread on variable rate (in hundredths)	1.50%
Revolving Credit Facility [Member] \| Alternate Base Rate [Member]
Debt Instrument [Line Items]
Interest rate, variable rate basis	Alternate Base Rate
Basis spread on variable rate (in hundredths)	0.50%
Line Of Credit [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	$ 1,194,000