Weighted Average Assumptions Used In Determining Pension Plan Information (Detail)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net Cost
Discount rate	4.73%	5.15%	5.62%
Expected return on plan assets	7.52%	7.93%	8.15%
Rate of compensation increase	3.76%	4.34%	4.35%
Benefit Obligation
Discount rate	3.89%	4.73%	5.15%
Rate of compensation increase	3.38%	3.76%	4.34%