Equity-Based Compensation, Profit Sharing and Deferred Compensation Plans - Equity-Based Compensation Plans (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding at beginning of period (Options)	737,702
Granted (Options)	84,073
Exercised (Options)	(148,578)
Forfeited (Options)	(34,119)
Expired (Options)
Outstanding at end of period (Options)	639,078
Exercisable at end of period (Options)	124,763
Outstanding at beginning of period (shares)	154,483
Granted (shares)	4,585
Exercised (shares)	(73,414)
Forfeited (shares)	(3,035)
Outstanding at end of period (shares)	82,619
Vested at end of period (shares)	73,101
Outstanding at beginning of period (Weighted Average Exercise Price)	$ 627.08
Granted (Weighted Average Exercise Price)	$ 808.53
Exercised (Weighted Average Exercise Price)	$ 492.75
Forfeited (Weighted Average Exercise Price)	$ 673.58
Expired (Weighted Average Exercise Price)
Outstanding at end of period (Weighted Average Exercise Price)	$ 679.70
Exercisable at end of period (Weighted Average Exercise Price)	$ 531.45
Outstanding at end of period (Weighted Average Remaining Contract Life (Years)	7 years 1 month 6 days
Exercisable at end of period (Weighted Average Remaining Contract Life (Years)	4 years 3 months 18 days
Outstanding at end of period (Aggregate Intrinsic Value)	$ 153,570
Exercisable at end of period (Aggregate Intrinsic Value)	48,477
Outstanding at end of period (Aggregate Intrinsic Value)	76,009
Vested at end of period (Aggregate Intrinsic Value)	$ 67,253