Equity Incentive Plans (Summary Of Exercisable Options) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended
	Jun. 30, 2012 Y
Options outstanding (in shares)	770,690
Weighted avg. life remaining (in years)	4.0
Weighted avg. exercise price	$ 36.55
Aggregate intrinsic value	$ 6,700
$18.18 - 19.99 [Member]
Exercise price range, lower limit	$ 18.18
Exercise price range, upper limit	$ 19.99
Options outstanding (in shares)	161,923
Weighted avg. life remaining (in years)	6.3
20.00 - 29.99 [Member]
Exercise price range, lower limit	$ 20.00
Exercise price range, upper limit	$ 29.99
Options outstanding (in shares)	168,971
Weighted avg. life remaining (in years)	0.7
30.00 - 39.99 [Member]
Exercise price range, lower limit	$ 30.00
Exercise price range, upper limit	$ 39.99
Options outstanding (in shares)	78,955
Weighted avg. life remaining (in years)	2.8
40.00 - 49.99 [Member]
Exercise price range, lower limit	$ 40.00
Exercise price range, upper limit	$ 49.99
Options outstanding (in shares)	247,488
Weighted avg. life remaining (in years)	4.5
50.00 - 59.99 [Member]
Exercise price range, lower limit	$ 50.00
Exercise price range, upper limit	$ 59.99
Options outstanding (in shares)	10,000
Weighted avg. life remaining (in years)	5.9
60.00 - 65.50 [Member]
Exercise price range, lower limit	$ 60.00
Exercise price range, upper limit	$ 65.50
Options outstanding (in shares)	103,353
Weighted avg. life remaining (in years)	4.6