Commitments and Contingencies (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Lease income and rental expense from operating leases
Rental and service income-operating leases	$ 80,715	$ 78,979	$ 77,916
Rental expense	$ 13,206us-gaap_LeaseAndRentalExpense	$ 13,751us-gaap_LeaseAndRentalExpense	$ 11,987us-gaap_LeaseAndRentalExpense

The total amount of revenue recognized for the period from operating leases, including minimum lease revenue, contingent revenue, percentage revenue and sublease revenue.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 25

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=7501430&loc=d3e39896-112707

Name:	us-gaap_OperatingLeasesIncomeStatementLeaseRevenue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration