Leasing Activity (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014
Operating Leases, Future Minimum Payments Receivable [Abstract]
2015	$ 540,996
2016	486,016
2017	400,297
2018	330,906
2019	258,777
Thereafter	1,019,497
Operating Leases, Future Minimum Payments Due	$ 3,036,489

Amount of minimum lease payments to be received by the lessor for capital leases in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 30

-Section 50

-Paragraph 4

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=25496975&loc=d3e45377-112738

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- Definition

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

+ References

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

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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 third year from the balance sheet date under an operating lease.

+ References

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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.

+ References

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