Equity-Based Compensation, Profit Sharing and Deferred Compensation Plans (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 Y	Dec. 31, 2010	Dec. 31, 2009
Stock Options
Outstanding at beginning of period (shares)	1,053,425
Outstanding at beginning of period (weighted average exercise price)	$ 529.18
Granted (shares)	39,960
Granted (weighted average exercise price)	$ 711.86
Exercised (shares)	(333,380)	359,765	418,775
Exercised (weighted average exercise price)	$ 324.92
Forfeited (shares)	(21,835)
Forfeited (weighted average exercise price)	$ 669.63
Expired (shares)	(468)
Expired (weighted average exercise price)	$ 769.40
Outstanding at end of period (shares)	737,702	1,053,425
Outstanding at end of period (weighted average exercise price)	$ 627.08	$ 529.18
Outstanding at end of period (weighted average remaining contract life (years)	6.9
Outstanding at end of period (aggregate intrinsic value)	$ 43,465
Exercisable at end of period (shares)	258,900
Exercisable at end of period (weighted average exercise price)	$ 509.73
Exercisable at end of period (weighted average remaining contract life (years))	4.1
Exercisable at end of period (aggregate intrinsic value)	45,636
RSUs
Outstanding at beginning of period	149,727
Granted	11,394
Forfeited (shares)	(6,638)
Outstanding at end of period (shares)	154,483	149,727
Outstanding at end of period (aggregate intrinsic value)	105,975
Exercisable at end of period (shares)	73,130
Exercisable at end of period (aggregate intrinsic value)	$ 50,167