Benefit Plans (Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	$ (80)
Cumulative net loss	10,658
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	388
Cumulative net loss	10,371
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	(468)
Cumulative net loss	$ 287