Summary Of Significant Accounting Policies (Schedule Of Operating Expenses By Category) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Summary Of Significant Accounting Policies [Abstract]
Salary and related	$ 279,058	$ 259,854	$ 261,035
Facilities	60,747	62,886	58,446
Vehicles	54,555	47,143	42,851
General supplies/miscellaneous	33,598	29,510	27,427
Total	$ 427,958	$ 399,393	$ 389,759