Stockholders' Equity (Summary Of Stock Option Transactions Relating To Non-Qualified Stock Option Plans) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011
Stockholders' Equity [Abstract]
No. of options, Outstanding at December 31, 2010	3,495
No. of options, Granted	575
No. of options, Exercised	(268)
No. of options, Cancelled	(149)
No. of options, Outstanding at December 31, 2011	3,653
No. of options, Exercisable at December 31, 2011	2,464
Weighted-Average Exercise Price of options, Outstanding at December 31, 2010	$ 16.95
Weighted-Average Exercise Price of options, Granted	$ 24.45
Weighted-Average Exercise Price of options, Exercised	$ 7.97
Weighted-Average Exercise Price of options, Cancelled	$ 21.02
Weighted-Average Exercise Price of options, Outstanding at December 31, 2011	$ 18.63
Weighted-Average Exercise Price of options, Exercisable at December 31, 2011	$ 17.55
Weighted-Average Remaining Contractual Term, in years, Outstanding at December 31, 2011	6.1
Weighted-Average Remaining Contractual Term, in years, Exercisable at December 31, 2011	4.9
Aggregate Intrinsic Value, Outstanding at December 31, 2011	$ 14,208
Aggregate Intrinsic Value, Exercisable at December 31, 2011	$ 12,157