Employee Benefit Plans (Changes In The Benefit Obligation And The Determination Of The Amounts Recognized) (Details) (Postretirement Medical Plan [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Postretirement Medical Plan [Member]
Projected benefit obligation at beginning of year	$ 98,417	$ 92,993
Defined Benefit Plan, Service Cost	1,679	1,441	1,405
Interest cost on projected benefit obligation	4,318	4,492	4,832
Actuarial loss (gain)	1,979	3,493	2,354
Participant contributions	3,265	2,911
Benefits paid	(7,367)	(6,913)
Plan amendments	0	0	(198)
Projected and accumulated benefit obligation at end of year	102,291	98,417	92,993
Funded status of the plan	(102,291)	(98,417)
Current liabilities	(6,588)	(6,822)
Long-term liabilities	(95,703)	(91,595)
Net amount recognized	$ (102,291)	$ (98,417)
Discount rate assumption as of December 31	3.60%	4.30%