Postretirement Health Care (Components of Net Periodic Postretirement Benefit Cost) (Details) (Other Postretirement Benefit Plans, Defined Benefit [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 450
Interest cost	721
Amortization of net (gain)/loss	0
Amortization of unrecognized transition (asset)/obligation	507
Net periodic postretirement benefit cost/(income)	$ 1,678