Future Minimum Lease Payments (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Future minimum lease payments
2013	$ 41,017
2014	39,594
2015	36,988
2016	32,869
2017	30,380
Thereafter	122,346
Total	$ 303,194

Future minimum rental payments in aggregate as of the balance sheet date under operating leases.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6454179&loc=d3e41551-112718

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 13

-Paragraph 23

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

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- Definition

Future rental payments receivable within one year of the balance sheet date under an operating lease.

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- Definition

Future rental payments receivable within the fifth year from the balance sheet date under an operating lease.

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Future rental payments receivable within the fourth year from the balance sheet date under an operating lease.

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Future rental payments receivable within the third year from the balance sheet date under an operating lease.

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Future rental payments receivable within the second year from the balance sheet date under an operating lease.

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- Definition

Future minimum lease payments receivable under operating leases for periods greater than five years following the balance sheet date.

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