Defined Benefit Pension Plans Defined Benefit Pension Plan Additional Information (Details) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Contributions by Employer	$ 34,000	$ 37,000	$ 355,000	$ 391,000	$ 520,000
Estimated Future Employer Contributions in Current Fiscal Year	$ 485,000		$ 485,000