Stock-Based Compensation Plans (Summary Of Plans' Restricted Share And Performance-Vested Stock Award Activity) (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Shares, Beginning of the Period	181,522	314,226
Shares, Granted	2,775	0
Shares, Vested and issued	(24,900)	(109,725)
Shares, Forfeited	(451)	(674)
Shares, Outstanding, End of the Period	158,946	203,827
Shares, Vested, but not issuable	85,000	85,000
Weighted Average Grant-Date Fair Value	$ 44.95	$ 41.40	$ 43.39	$ 37.99
Weighted Average Grant-Date Fair Value, Granted	$ 46.86	$ 0.00
Weighted Average Grant-Date Fair Value, Vested and issued	$ 33.81	$ 31.67
Weighted Average Grant-Date Fair Value, Forfeited	$ 44.29	$ 32.10
Weighted Average Grant-Date Fair Value, Vested, but not issuable	$ 51.88	$ 51.88
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Shares, Beginning of the Period	307,512	214,565
Shares, Granted	91,501	102,160
Shares, Vested and issued	(15,944)	0
Shares, Forfeited	(81,551)	(2,359)
Shares, Outstanding, End of the Period	301,518	314,366
Weighted Average Grant-Date Fair Value	$ 38.12	$ 33.95	$ 34.01	$ 32.08
Weighted Average Grant-Date Fair Value, Granted	$ 46.86	$ 37.84
Weighted Average Grant-Date Fair Value, Vested and issued	$ 33.25	$ 0.00
Weighted Average Grant-Date Fair Value, Forfeited	$ 33.38	$ 33.02