Employee Benefit Plans Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Net (losses) gains	$ (75,995)	$ 1,348	$ 7,778
Prior service cost	0	(1,704)	(5,352)
Amortization of losses	10,372	6,456	6,196
Amortization of prior service cost (benefit)	1,359	1,657	1,830
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Net (losses) gains	(3,934)	(965)	(533)
Prior service cost	631	0	0
Amortization of losses	570	3,357	5,841
Amortization of prior service cost (benefit)	$ 69	$ (5,334)	$ (9,480)