Benefit Plans (Summary Of Restricted Stock Activity) (Details) (Performance-Contingent Restricted Stock [Member], USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested, January 1 (in shares/awards)	211,651		301,738		296,190
Nonvested shares, January 1, weighted average fair value (in dollars per share)	$ 32.42		$ 32.60		$ 32.32
Granted (in shares)	49,093		45,612		64,217
Granted, weighted average fair value (in dollars per share)	$ 47.58		$ 43.05		$ 38.75
Vested (in shares)	0	[1]	(65,172)	[1]	(53,274)	[1]
Vested, weighted average fair value (in dollars per share)	$ 0.00	[1]	$ 32.56	[1]	$ 37.93	[1]
Forfeited (in shares)	(101,822)	[2]	(70,527)	[2]	(5,395)	[2]
Forfeited, weighted average fair value (in dollars per share)	$ 23.67	[2]	$ 39.93	[2]	$ 38.00	[2]
Nonvested, December 31 (in shares/awards)	158,922		211,651		301,738
Nonvested shares, December 31, weighted average fair value (in dollars per share)	$ 42.71		$ 32.42		$ 32.60
Performace Criteria Not Met [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Forfeited (in shares)	(101,822)		(65,516)

[1] In 2012 and 2011, 65,172 and 53,274 performance-contingent restricted shares granted in 2010 and 2007, respectively, vested because the specified performance criteria for such shares were met.

[2] In 2013 and 2012, 101,822 and 65,516 performance-contingent restricted shares granted in 2009 and 2008, respectively, were forfeited because the specified performance criteria for such shares were not met. The remaining forfeitures during 2012 and 2011 were primarily caused by retirements and terminations of participants.