Stock-Based Compensation Plans (Summary Of Stock Option Activity Under All Plans) (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value of stock options outstanding	$ 14,303
Aggregate intrinsic value of stock options exercisable	13,292
Aggregate intrinsic values of stock options expected to vest	$ 14,248
Weighted average remaining contractual lives of stock options outstanding, years	3 years 8 months 12 days
Weighted average remaining contractual lives of stock options exercisable, years	3 years 3 months 18 days
Weighted average remaining contractual lives of stock options expected to vest, years	3 years 8 months 12 days
Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding, beginning of period, Shares	1,501		2,068
Granted, shares	29		25
Exercised, shares	(622)		(466)
Expired, shares			(10)
Options outstanding, end of period, Shares	908		1,617
Options exercisable, end of period, Shares	840	[1]	1,464	[1]
Options vested and expected to vest, end of period, Shares	905	[1]	1,610	[1]
Weighted average fair value of options granted during the period	$ 15.18	[1]	$ 13.18	[1]
Options outstanding, beginning of period, Exercise Price	$ 31		$ 31
Granted, Exercise Price	$ 44		$ 37
Exercised, Exercise Price	$ 29		$ 29
Expired, Exercise Price	$ 0		$ 38
Options outstanding, end of period, Exercise Price	$ 33	[1]	$ 31	[1]
Options exercisable, end of period, Exercise Price	$ 33	[1]	$ 33	[1]
Options vested and expected to vest, end of period, Exercise Price	$ 33	[1]	$ 31	[1]

[1] At June 30, 2012, the aggregate intrinsic value of stock options outstanding, exercisable and vested/expected to vest was $14,303, $13,292 and $14,248, respectively. At that same date, the weighted average remaining contractual lives of stock options outstanding, exercisable and vested/expected to vest was 3.7 years, 3.3 years and 3.7 years, respectively.