Employee Benefits (Schedule Of Change In Benefit Obligation) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation, beginning of year	$ 54,033	$ 52,059
Service cost	930	938	842
Interest cost	2,723	2,751	2,465
Actuarial loss (gain)	4,358	326
Benefits paid	(2,168)	(2,041)
Benefit obligation, end of year	59,876	54,033	52,059
Post-Retirement Healthcare Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation, beginning of year	20,047	21,048
Service cost	16	45	85
Interest cost	840	919	1,067
Actuarial loss (gain)	816	(656)
Benefits paid	(1,507)	(1,309)
Benefit obligation, end of year	$ 20,212	$ 20,047	$ 21,048