Retirement Plan (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Defined Benefit Plan Disclosure [Line Items]
Pension curtailment adjustment	$ 7,102,000	$ 0	$ 7,102,000	$ 0
Other Comprehensive Income (Loss), Finalization of Pension and Non-Pension Postretirement Plan Valuation, before Tax	7,102,000		7,102,000
Expected long-term annual rate of return on plan assets			6.50%
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated contributions in 2012	22,400,000		22,400,000
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Amendments	3,500,000		6,900,000
Estimated effect of curtailment	$ 674,000	$ 0	$ 899,000	$ 0