Employee Benefit Plans (Changes In The Benefit Obligation And The Determination Of The Amounts Recognized) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Long-term liabilities	$ (610,850)	$ (418,731)
Postretirement Medical Plan [Member]
Projected benefit obligation at beginning of year	92,993	89,843
Service cost	1,441	1,405	1,539
Interest cost on projected benefit obligation	4,492	4,832	5,578
Actuarial loss	3,493	2,354	(10,353)
Participant contributions	2,911	2,856
Plan amendments		(198)
Benefits paid	(6,913)	(8,099)
Projected and accumulated benefit obligation at end of year	98,417	92,993	89,843
Funded status of the plan	(98,417)	(92,993)
Current liabilities	(6,822)	(6,763)
Long-term liabilities	(91,595)	(86,230)
Net amount recognized	$ (98,417)	$ (92,993)
Discount rate assumption as of December 31	4.30%	5.00%