Commitments And Contingencies (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Commitments And Contingencies [Line Items]
Litigation reserves and payments		$ 1,235,000	$ 700,000
Operating leases, expiration range	2012 and 2021
Rent expense	28,500,000	23,300,000	21,000,000
Short-term deferred lease obligation	1,000,000	1,800,000
Long-term deferred lease obligation	5,300,000	4,800,000
Standby Letters Of Credit [Member]
Commitments And Contingencies [Line Items]
Standby letters of credit	$ 2,300,000	$ 2,100,000