Components Of Pension Plan Net Periodic Benefit Costs (Summary Of Components Of Pension Plan Net Periodic Benefit Costs) (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Components Of Pension Plan Net Periodic Benefit Costs
Service cost	$ 618	$ 713	$ 1,236	$ 1,426
Interest cost	788	840	1,576	1,679
Expected return on plan assets	(973)	(924)	(1,945)	(1,846)
Amortization of net loss	122	269	244	538
Net periodic benefit cost	$ 555	$ 898	$ 1,111	$ 1,797