Rentals Under Operating Leases Rentals Under Operating Leases (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Property Subject to or Available for Operating Lease [Line Items]
Operating Leases, Future Minimum Payments Receivable, Current	$ 61,220
Operating Leases, Future Minimum Payments Receivable, in Two Years	40,268
Operating Leases, Future Minimum Payments Receivable, in Three Years	33,469
Operating Leases, Future Minimum Payments Receivable, in Four Years	28,565
Operating Leases, Future Minimum Payments Receivable, in Five Years	19,500
Operating Leases, Future Minimum Payments Receivable, Thereafter	56,541
Operating Leases, Future Minimum Payments Receivable	$ 239,563

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

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

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- Definition

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

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- Definition

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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