Components of Rental Income and Expense (Components Of Rental Expenses) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Component of Operating Other Cost and Expense [Line Items]
Rental expenses	$ 29,679	$ 26,595	$ 82,695	$ 81,130

Costs incurred and are directly related to generating revenues from leased and rented property or equipment.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.2(c))

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Name:	us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration