Stock-Based Compensation Plans (Summary Of Stock Option Activity) (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Common Shares, Outstanding at beginning of the period		1,551,734	1,618,426
Common Shares, Conversion of options of acquired company			16,364
Common Shares, Granted		554,107	487,259
Common Shares, Exercised		(19,110)	(51,522)
Common Shares, Forfeited or canceled		(57,004)	(175,579)
Common Shares, Outstanding at end of the period		2,029,727	1,894,948
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Weighted Average Strike Price, Outstanding at beginning of period		$ 41.32	$ 43.00
Weighted Average Strike Price, Conversion of options of acquired company			21.18
Weighted Average Strike Price, Granted		40.87	44.11
Weighted Average Strike Price, Exercised		32.86	31.50
Weighted Average Strike Price, Forfeited or canceled		51.08	54.40
Weighted Average Strike Price, Outstanding at end of period		$ 41.00	$ 42.35
Stock Options, Exercisable		983,659	1,158,991
Stock Options, Weighted Average Strike Price, Exercisable		$ 39.13	$ 41.00
Stock Options, Remaining Contractual Term, Outstanding, Years	[1]	5 years	4 years 7 months 6 days
Stock Options, Remaining Contractual Term, Exercisable, Years	[1]	3 years 9 months 18 days	3 years 3 months 18 days
Stock Options, Intrinsic Value, Outstanding	[2]	$ 7,951	$ 11,649
Stock Options, Intrinsic Value, Exercisable	[2]	$ 5,885	$ 9,291

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

[2] Aggregate intrinsic value represents the total pre-tax intrinsic value (i.e., the difference between the Company's 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. Options with exercise prices above the stock price on the last trading day of the quarter are excluded from the calculation of intrinsic value. The intrinsic value will change based on the fair market value of the Company's stock.