Pension and Other Postretirement Benefits (Details 8)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
US Plan [Member]
Computing net pension expense for the plans
Discount rate	4.50%	5.50%
Expected return on plan assets	7.50%	7.50%
Canadian Plan [Member]
Computing net pension expense for the plans
Discount rate	4.13%	6.25%
Expected return on plan assets	6.00%	7.00%
Rate of compensation increase	2.00%	2.00%