Employee Benefit Plans (Assumptions) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Expected long-term return on plan assets	7.25%
Rate of compensation increase for pay-related plans	3.75%
Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]
Health care cost trend rate assumed for next year	7.00%	8.50%
Rate to which the cost trend rate is assumed to decline	5.00%	5.50%
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract]
Effect on total service and interest cost, 1-Percentage Point Decrease	(414)
Effect on total service and interest cost, 1-Percentage Point Increase	504
Effect on net postretirement benefit obligation, 1-Percentage Point Decrease	(4,503)
Effect on net postretirement benefit obligation, 1-Percentage Point Increase	5,313
Pension Plans
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	4.89%	5.49%	6.50%
Expected long-term return on plan assets	7.25%	7.25%	8.25%
Rate of compensation increase for pay-related plans	3.75%	3.95%	3.90%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	4.52%	4.89%
Rate of compensation increase for pay-related plans	3.59%	3.75%
Postretirement Benefit Plans
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	5.45%	5.90%	6.50%
Expected long-term return on plan assets	7.25%	7.25%	8.25%
Rate of compensation increase for pay-related plans	3.61%	3.69%	3.55%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	4.95%	5.45%
Rate of compensation increase for pay-related plans	3.55%	3.61%