Equity Incentive Plans (Summary Of Outstanding Options) (Details) (USD $) In Thousands, except Share data, unless otherwise specified					12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2011 $18.18 - 19.99 [Member]	Dec. 31, 2011 20.00 - 29.99 [Member]	Dec. 31, 2011 30.00 - 39.99 [Member]	Dec. 31, 2011 40.00 - 49.99 [Member]	Dec. 31, 2011 50.00 - 59.99 [Member]	Dec. 31, 2011 60.00 - 65.50 [Member]
Exercise price range, lower limit					$ 18.18	$ 20.00	$ 30.00	$ 40.00	$ 50.00	$ 60.00
Exercise price range, upper limit					$ 19.99	$ 29.99	$ 39.99	$ 49.99	$ 59.99	$ 65.50
Options outstanding	1,002,833	1,071,096	1,208,288	911,117	310,807	172,304	96,303	310,066	10,000	103,353
Weighted avg. life remaining	5.1				7.1	1.2	4.1	5.7	6.4
Weighted avg. exercise price	$ 34.41	$ 32.00	$ 30.27	$ 34.07
Aggregate intrinsic value	$ 11,992