Employee Benefits (Expected Future Benefit Payments) (Details) (USD $)	Dec. 31, 2011
Retirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year	$ 19,800,000
Retirement Income Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2012	9,132,000
2013	9,967,000
2014	10,932,000
2015	11,924,000
2016	13,021,000
2017-2021	83,027,000
Non-Qualified Retirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2012	1,844,000
2013	1,813,000
2014	1,777,000
2015	1,758,000
2016	1,801,000
2017-2021	$ 9,430,000