Obligations under capital lease (Details 2) (USD $) In Thousands, unless otherwise specified	6 Months Ended
Jun. 30, 2012
Capital Leases, Future Minimum Payments Due [Abstract]
2012	$ 2,291
2013 through 2016 ($4,582 annually)	18,328
Thereafter	12,100
Less: Interest	(5,888)
Net minimum lease payments under capital lease	26,831
Less: Current portion of net minimum lease payments	(4,448)
Long-term portion of net minimum lease payments	$ 22,383

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Contractually required rental payments on leases meeting the criteria for capitalization, due within one year of the balance sheet date.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 13

-Paragraph 16

-Subparagraph a(ii)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6455398&loc=d3e45280-112737

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- Definition

Contractually required rental payments due on leases meeting the criteria for capitalization, after the fifth year from the balance sheet date.

+ References

+ Details

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- Definition

The total contractually required rental payments on capitalized leases net of deductions for: (i) executory costs, including any profit thereon, included in the minimum lease payments and (ii) the amount of imputed interest necessary to reduce the net minimum lease payments to present value.

+ References

+ Details

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- Definition

The amount, during the lease term, of each minimum [capital] lease payment allocated to interest expense so as to produce a constant periodic rate of interest on the remaining balance of the capital lease obligation.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 13

-Paragraph 12

-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.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.8)

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 30

-Section 35

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6916424&loc=d3e43161-112731

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- Definition

Contractually required rental payments on leases meeting the criteria for capitalization, due in year two through year five.

+ References

No definition available.

+ Details

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- Definition

The total current contractually required rental payments on capitalized lease

+ References

No definition available.

+ Details

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- Definition

The total contractually required rental payments on capitalized leases net of current portion of lease payments

+ References

No definition available.

+ Details

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