Equity Compensation (Stock Options Granted, Forfeited, Exercised And Expired) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010	Sep. 30, 2011		Sep. 30, 2010
Equity Compensation [Abstract]
Number of Shares, Outstanding at beginning of period				1,724,791
Number of Shares, Granted	0		0	159,500		305,000
Number of Shares, Forfeited				0
Number of Shares, Exercised	(8,800)		(101,550)	(112,110)		(172,879)
Number of Shares, Expired				0
Number of Shares, Outstanding at end of period	1,772,181			1,772,181
Number of Shares, Exercisable at end of period	1,326,000			1,326,000
Weighted Average Exercise Price, Outstanding at beginning of period				$ 77.95
Weighted Average Exercise Price, Granted	$ 69.43			$ 69.43
Weighted Average Exercise Price, Forfeited	$ 0.00			$ 0.00
Weighted Average Exercise Price, Exercised	$ 47.15			$ 47.15
Weighted Average Exercise Price, Expired	$ 0.00			$ 0.00
Weighted Average Exercise Price, Outstanding at end of period	$ 79.13			$ 79.13
Weighted Average Exercise Price, Exercisable at end of period	$ 72.38			$ 72.38
Aggregate Exercise Price, Outstanding at beginning of period				$ 134,447
Aggregate Exercise Price, Granted	11,074			11,074
Aggregate Exercise Price, Forfeited	0			0
Aggregate Exercise Price, Exercised	(5,286)			(5,286)
Aggregate Exercise Price, Expired	0			0
Aggregate Exercise Price, Outstanding at end of period	140,235			140,235
Aggregate Exercise Price, Exercisable at end of period	95,970			95,970
Weighted Average Remaining Contractual Term, Outstanding at end of period, years	3.8			3.8
Weighted Average Remaining Contractual Term, Exercisable at end of period, years				3.1
Aggregate Intrinsic Value, Outstanding at end of period	7,941	[1]		7,941	[1]
Aggregate Intrinsic Value, Exercisable at end of period	$ 7,941	[1]		$ 7,941	[1]

[1] The aggregate intrinsic value of the stock options was calculated by identifying those stock options that had a lower exercise price than the closing market price of our common stock on September 30, 2011 and multiplying the difference between the closing market price of our common stock and the exercise price of each of those stock options by the number of shares subject to those stock options that were outstanding or exercisable, as applicable.