Assumptions Used to Determine Benefit Obligations (Detail)	Dec. 31, 2013	Dec. 31, 2012
Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.75%	3.75%
Long-term rate of compensation increase	4.50%	4.50%
Other post-retirement benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.75%	3.75%
Long-term rate of compensation increase	4.50%	4.50%