Fair Value Measurements (Schedule Of Non-Recurring Losses Recognized Using Fair Value Measurements And The Carrying Value Of Any Assets And Liabilities Measured Using Fair Value Estimates) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, Carrying Value	$ 7,354	$ 48,420	$ 36,295
Assets, Non-Recurring Losses	1,751		373
Liabilities, Carrying Value		399	932
Liabilities, Non-Recurring Losses	50	203	87
Vacant Leased Facilities [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Liabilities, Carrying Value		399	932
Liabilities, Non-Recurring Losses	50	203	87
Vacant Owned Facilities [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, Carrying Value	5,009	10,031	11,559
Assets, Non-Recurring Losses	523		373
Net Assets Of Acquired Businesses [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, Carrying Value	1,345	38,389	24,736
Other Indentifiable Intangible Assets [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, Non-Recurring Losses	$ 1,228