Long-term debt Long-Term Debt--Capital Leases (Details) (U.S. Bank National Association, Capital Lease Obligations, USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2014
U.S. Bank National Association \| Capital Lease Obligations
Debt Instrument [Line Items]
Proceeds from sale leaseback	$ 24,500
Lease term	84 months
Purchase option period	72 months
Implicit interest rate	3.80%
Minimum lease payments	$ 3,181

Sale Leaseback Transaction, Lease, Option Purchase Period

No definition available.

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- Definition

Sale Leaseback Transaction, Lease Term

+ References

No definition available.

+ Details

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- Details

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- Definition

The yearly payments due under the lease entered into in connection with the transaction involving the sale of property to another party and the lease of the property back to the seller.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6452660&loc=d3e36991-112694

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 40

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6456341&loc=d3e50796-112755

+ Details

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- Definition

The gross proceeds received from the asset(s) sold in connection with the transaction involving the sale of property to another party and the lease back to the seller.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 40

-Section 55

-Paragraph 51

-URI http://asc.fasb.org/extlink&oid=28365400&loc=d3e51840-112757

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 40

-Section 55

-Paragraph 52

-URI http://asc.fasb.org/extlink&oid=28365400&loc=d3e51843-112757

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 40

-Section 55

-Paragraph 50

-URI http://asc.fasb.org/extlink&oid=28365400&loc=d3e51831-112757

+ Details

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Balance Type:	debit
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- Definition

The financing cost related to leases that have been recorded under the deposit method, as a financing or as a capital leases in connection with the transaction involving the sale of property to another party and the lease of the property back to the seller.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Imputed Interest Rate

-URI http://asc.fasb.org/extlink&oid=6515215

+ Details

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