Long-Term Bank Debt (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Long-Term Debt (Textual) [Abstract]
Percentage for base rate loans at the prime rate	3.25%
Long-Term Debt (Additional Textual) [Abstract]
Credit facility borrowing capacity	$ 250
Maturity date of Amended and Restated Credit Agreement	Jul. 30, 2017
Credit facility borrowing base	145.0
Credit facility, interest rate description	The Company’s borrowing rates in the credit facility provide for base rate loans at the prime rate (3.25% at March 31, 2013) plus applicable margin utilization rates that range from 1.75% to 2.00%, and LIBO rate loans at LIBO published rates plus applicable utilization rates (2.75% to 3.00% at March 31, 2013). At March 31, 2013, the Company had in place one base rate loan and one LIBO rate loan with effective rates of 5.00% and 2.95%, respectively
Minimum range for applicable margin utilization rate	1.75%
Maximum range for applicable margin utilization rate	2.00%
Debt instrument interest one base rate basis for effective rate	5.00%
Effective LIBOR Loan Rate	2.95%
Outstanding borrowings under revolving credit facility	122.0
Weighted-average interest rate of borrowings	3.57%
Credit facility remaining borrowing capacity	23.0
Debt instrument basis weighted average interest rate spread on variable rate	3.57%	3.93%
Interest Rate Swap [Member]
Long-Term Debt (Textual) [Abstract]
Interest swap agreements period	2 years
Company bank debt	$ 75
Percentage for base rate loans at the prime rate	0.563%
Maximum [Member]
Long-Term Debt (Textual) [Abstract]
LIBOR rate loans	3.00%
Minimum [Member]
Long-Term Debt (Textual) [Abstract]
LIBOR rate loans	2.75%

Debt instrument basis weighted average interest rate spread on variable rate.

No definition available.

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Debt instrument interest one base rate basis for effective rate.

+ References

No definition available.

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- Definition

Effective LIBOR loan rate.

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No definition available.

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- Definition

Term of derivative interest rate swap.

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No definition available.

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- Definition

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

+ References

No definition available.

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- Definition

Including current and noncurrent portions, aggregate carrying amount of long-term borrowings as of the balance sheet date before deducting unamortized discount or premiums (if any). May include notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, which had initial maturities beyond one year or beyond the normal operating cycle, if longer.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number APB14-1

-Paragraph 31

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5

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-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

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-Name Regulation S-X (SX)

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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

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-Paragraph 1

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

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- Definition

When presenting a range of interest rates, the highest effective rate for funds borrowed under the debt agreement 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 22

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

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

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- Definition

When presenting a range of interest rates, the lowest effective rate for funds borrowed under the debt agreement as of the balance sheet date.

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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

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- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any 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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-Name Regulation S-X (SX)

-Number 210

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-Paragraph 19, 22

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- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

+ References

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- Definition

Description of the interest rate for the amounts borrowed under the credit facility, including the terms and the method for determining the interest rate (for example, fixed or variable, LIBOR plus a percentage, increasing rate, timing of interest rate resets, remarketing provisions).

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 2, 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

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-Subparagraph (SX 210.5-02.19(b),22(b))

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

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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

+ Details

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- 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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- Definition

Reflects the calculation as of the balance sheet date of the average interest rate weighted by the amount of long-term debt outstanding by type or by instrument at that time.

+ References

No definition available.

+ Details

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