Represents the credit facility term.

No definition available.

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- Definition

Represents the debt instrument, number of annual principal repayments.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
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- Details

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- Definition

Represents the number of annual principal payments.

+ References

No definition available.

+ Details

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- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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-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

+ Details

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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

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

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-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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Data Type:	num:percentItemType
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- Definition

Amount of the required periodic payments including both interest and principal payments.

+ 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)

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-Name Regulation S-X (SX)

-Number 210

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-SubTopic 470

-Section 50

-Paragraph 3

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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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Balance Type:	na
Period Type:	duration

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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

+ Details

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

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

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- Definition

The cash inflow associated with the amount received from entity's raising of capital via private rather than public placement.

+ 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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-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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Balance Type:	debit
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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.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

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-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16(a))

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

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Namespace Prefix:	us-gaap_
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Balance Type:	credit
Period Type:	instant

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Note 12 - Long-term Debt (Details) (USD $)	0 Months Ended	12 Months Ended	0 Months Ended
Note 12 - Long-term Debt (Details) (USD $)	Jan. 16, 2014	Dec. 31, 2014	Jan. 16, 2013	Dec. 31, 2013
Note 12 - Long-term Debt (Details) [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity (in Dollars)		$ 500,000,000
Credit Facility Term		5 years
Debt, Weighted Average Interest Rate		1.60%us-gaap_DebtWeightedAverageInterestRate		2.00%us-gaap_DebtWeightedAverageInterestRate
Line of Credit Facility, Remaining Borrowing Capacity (in Dollars)		155,583,000		166,349,000
Letters of Credit Outstanding, Amount (in Dollars)		7,856,000		7,770,000
Debt Instrument, Interest Rate, Effective Percentage		3.00%		4.50%
Proceeds from Issuance of Private Placement (in Dollars)	5,000
Beginning January 16, 2021 [Member]
Note 12 - Long-term Debt (Details) [Line Items]
Debt Instrument, Number of Annual Principal Repayments			5
3.84% Notes [Member]
Note 12 - Long-term Debt (Details) [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			3.84%
Senior Notes (in Dollars)			150,000,000
Debt Instrument, Term			12 years
6.40% Senior Notes [Member]
Note 12 - Long-term Debt (Details) [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		6.40%
Senior Notes (in Dollars)		12,500,000		25,000,000
Debt Instrument, Number of Annual Principal Repayments		4
5.44% Senior Notes [Member]
Note 12 - Long-term Debt (Details) [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.44%
Senior Notes (in Dollars)		20,000,000		40,000,000
Number Of Annual Principal Payments		5
Debt Instrument, Periodic Payment (in Dollars)		$ 20,000
Minimum [Member]
Note 12 - Long-term Debt (Details) [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		1.25%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage		0.25%
Debt Instrument, Term		1 year
Maximum [Member]
Note 12 - Long-term Debt (Details) [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		3.00%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage		0.60%
Debt Instrument, Term		10 years