Commitments and Contingencies (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Commitments and Contingencies Disclosure [Abstract]
Lease expiration date, maximum	Jan. 01, 2020
Rent expense	$ 17,524	$ 17,375	$ 16,215
Minimum rentals for aggregate lease commitments
2013	8,469
2014	4,252
2015	2,555
2016	1,247
2017	209
Thereafter	89
Total	16,821
Aggregate residual value at lease expiration for vehicle leases	11,334
Guaranteed aggregate residual value at lease expiration for vehicle leases	7,231
Liability for the estimated end-of-term loss related to residual value guarantee	536
Term of unrecorded unconditional purchase obligation	three year
Minimum purchase obligation	$ 2,102

The aggregate residual value at lease expiration for vehicle leases.

No definition available.

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Estimated end-of-term loss related to residual value guarantee as of Balance Sheet date.

+ References

No definition available.

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The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

+ References

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- Definition

Date which lease or group of leases is set to expire, in CCYY-MM-DD format.

+ References

No definition available.

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- Definition

The minimum amount the entity agreed to spend under the long-term purchase commitment.

+ References

No definition available.

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Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

+ References

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-Name Statement of Financial Accounting Standard (FAS)

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-Paragraph 16

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Amount of required minimum rental payments maturing in the next fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

+ References

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Amount of required minimum rental payments maturing in the fifth fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing in the forth fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing in the third fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing in the second fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing after the fifth fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.

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Describes the term of the unconditional purchase obligation that is not recorded as a liability on the balance sheet.

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