CONSOLIDATED STATEMENTS OF CASH FLOWS INFORMATION (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplemental Cash Flow Elements [Abstract]
Cash paid for interest	$ 7,529us-gaap_InterestPaid	$ 5,065us-gaap_InterestPaid	$ 5,721us-gaap_InterestPaid
Income tax payments	6,943us-gaap_IncomeTaxesPaid	7,376us-gaap_IncomeTaxesPaid	7,221us-gaap_IncomeTaxesPaid
Income tax refunds	1,352us-gaap_ProceedsFromIncomeTaxRefunds	1,060us-gaap_ProceedsFromIncomeTaxRefunds	1,697us-gaap_ProceedsFromIncomeTaxRefunds
Capital lease additions	2,016us-gaap_CapitalLeaseObligationsIncurred	2,708us-gaap_CapitalLeaseObligationsIncurred	1,722us-gaap_CapitalLeaseObligationsIncurred
Capitalized interest	$ 312us-gaap_InterestPaidCapitalized	$ 274us-gaap_InterestPaidCapitalized	$ 212us-gaap_InterestPaidCapitalized

The increase during the period in capital lease obligations due to entering into new capital leases.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4313-108586

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

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The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

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- Definition

The amount of cash paid for interest during the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

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-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4297-108586

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The amount of cash paid during the current period for interest that is capitalized.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

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-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4297-108586

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- Definition

The amount of cash received during the period as refunds for the overpayment of taxes.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

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