Significant Accounting Policies (Details 4) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Deferred Lease Costs
Portion of compensation capitalized	$ 15.1	$ 12.4	$ 11.0
Estimated average lease term	7 years
Joint venture
Investment in Unconsolidated Joint Ventures
Recourse debt	$ 18.4
Number of joint ventures with debt recourse (joint ventures)	1

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Represents the amount of deferred lease costs capitalized during the period.

+ References

No definition available.

+ Details

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- Definition

The number of joint ventures to whom the entity provides guarantees in the form of recourse for debt.

+ References

No definition available.

+ Details

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- Definition

Represents the estimated average term of the operating leases.

+ References

No definition available.

+ Details

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- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph (b)(1)

-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248

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- Details

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