Benefit Plans (Change In Projected Benefit Obligation) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Benefit Plans [Abstract]
Projected benefit obligation at beginning of year	$ 108,146		$ 97,532
Service cost	5,951		5,544		5,216
Interest cost	6,147		5,709		5,059
Plan amendments	338		13
Actuarial loss	16,678		2,243
Benefits paid	(3,464)		(2,895)
Projected benefit obligation at end of year	133,796		108,146		97,532
Fair value of plan assets at beginning of year	83,937	[1]	74,005
Actual return on plan assets	2,168		7,731
Employer contributions	13,105		5,096
Benefits paid	(3,464)		(2,895)
Fair value of plan assets at end of year	95,746	[1]	83,937	[1]	74,005
Funded status of the plan	(38,050)		(24,209)
Liability recognized	(38,050)		(24,209)
Accumulated benefit obligation	120,564		96,360
Accrued interest receivable	$ 309		$ 299

[1] Includes accrued interest receivable of $309 thousand and $299 thousand as of December 31, 2011 and 2010, respectively.