Stock-Based Compensation Plans (Summary Of Stock Option Activity) (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding at beginning of the period	2,064,534		2,040,701
Stock Options, Granted	250,997		10,000
Stock Options, Exercised	(421,426)		(48,883)
Stock Options, Forfeited or canceled	(50,235)		(103,149)
Outstanding at end of the period	1,843,870		1,898,669
Stock Options, Exercisable	1,840,731		1,717,762
Stock Options, Weighted Average Strike Price	$ 42.09		$ 39.07		$ 38.83	$ 38.92
Stock Options, Weighted Average Strike Price, Granted	$ 31.16		$ 31.00
Stock Options, Weighted Average Strike Price, Exercised	$ 20.27		$ 15.90
Stock Options, Weighted Average Strike Price, Forfeited or canceled	$ 36.42		$ 46.30
Stock Options, Weighted Average Strike Price, Exercisable	$ 42.11		$ 39.85
Stock Options, Remaining Contractual Term, Outstanding, Years	3 years 2 months 12 days	[1]	2 years 7 months 6 days	[1]
Stock Options, Remaining Contractual Term, Exercisable, Years	3 years 2 months 12 days	[1]	2 years 3 months 18 days	[1]
Stock Options, Intrinsic Value, Outstanding	$ 5,029	[2]	$ 3,028	[2]
Stock Options, Intrinsic Value, Exercisable	$ 5,010	[2]	$ 2,818	[2]

[1] Represents the weighted average contractual life remaining in years.

[2] Aggregate intrinsic value represents the total pre-tax intrinsic value (i.e., the difference between the Company’s average of the high and low stock price on the last trading day of the quarter and the option exercise price, multiplied by the number of shares) that would have been received by the option holders if they had exercised their options on the last day of the quarter. This amount will change based on the fair market value of the Company’s stock.