Equity Compensation (Stock Options Granted And Exercised) (Details) (USD $) In Thousands, except Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Equity Compensation [Abstract]
Shares subject to stock options granted	0	0	159,500	305,000
Weighted average grant date fair value per share	$ 0.00	$ 0.00	$ 28.90	$ 43.59
Shares subject to stock options exercised	8,800	101,550	112,110	172,879
Intrinsic value of stock options exercised	$ 469	$ 3,410	$ 3,039	$ 8,582
Proceeds received from stock options exercised	303	5,210	5,286	7,830
Tax benefits realized from stock options exercised	$ 180	$ 1,313	$ 1,169	$ 3,255