Assumptions Used to Determine Periodic Benefit Cost (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Long-term rate of return on funded assets	6.25%
Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.75%	4.25%	5.50%
Long-term rate of return on funded assets	6.25%	6.25%	7.00%
Long-term rate of compensation increase	4.50%	4.50%	4.50%
Other post-retirement benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.75%	4.25%	5.50%
Long-term rate of compensation increase	4.50%	4.50%	4.50%