Pension Plan (Schedule Of Reconciliation Of Defined Benefit Pension Plan) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Pension Plan [Abstract]
Fair value of plan assets at beginning of year	$ 73,402	$ 61,451
Actual return (loss) on plan assets	5,689	10,027
Employer contributions	14,065	6,657
Benefits paid	(4,541)	(4,256)
Administrative expenses	(675)	(477)
Fair value of plan assets at end of year	87,940	73,402	61,451
Benefit obligation at beginning of year	93,513	85,476
Service cost	1,162	1,140	1,191
Interest cost	5,047	4,958	4,834
Actuarial (gain) loss	13,265	6,195
Benefit obligation at end of year	108,446	93,513	85,476
Other noncurrent liabilities	20,506	20,110
Total liability at end of year	20,506	20,110
Projected benefit obligation	108,446	93,513
Accumulated benefit obligation	106,609	91,559
Fair value of plan assets	$ 87,940	$ 73,402	$ 61,451