Employee Benefit Plans Net Periodic Benefit Cost (Details) (USD $) In Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Pension Plans, Defined Benefit [Member]
Components of Net Periodic Benefit Cost [Abstract]
Service cost	$ 2,549	$ 2,340	$ 7,649	$ 7,021
Interest cost	6,099	6,023	18,296	18,068
Expected return on plan assets	(7,616)	(7,459)	(22,847)	(22,379)
Amortization of prior service cost	62	62	185	185
Recognized actuarial loss	629	34	1,887	104
Net Periodic Benefit Cost (Income)	1,723	1,000	5,170	2,999
Other Pension Plans, Postretirement or Supplemental Plans, Defined Benefit [Member]
Components of Net Periodic Benefit Cost [Abstract]
Service cost	109	120	328	362
Interest cost	337	450	1,011	1,352
Expected return on plan assets	(296)	(297)	(889)	(890)
Amortization of prior service cost	(500)	(488)	(1,499)	(1,464)
Recognized actuarial loss	165	247	494	738
Net Periodic Benefit Cost (Income)	$ (185)	$ 32	$ (555)	$ 98