Weighted Average Assumptions Used (Details)	Dec. 31, 2012	Dec. 31, 2011
Compensation and Retirement Disclosure [Abstract]
Discount rate	2.80%	4.00%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation Average remaining service life at year end	12 years 9 months 18 days	13 years 7 months 6 days
Average rate of future compensation increase	2.50%	2.50%