Employee Pension Benefits - Schedule of Changes in Components of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Compensation and Retirement Disclosure [Abstract]
Accumulated Other Comprehensive Income (Loss) Before Tax - Beginning Balance	$ 5,032
Amortization of Prior service costs (credits)- Before Tax	(389)
Accumulated Other Comprehensive Income (Loss) Before Tax - Ending Balance	4,643
Income Tax Benefit (Expense) - Beginning Balance	(1,886)
Amortization of Prior service costs (credits)- Tax Effect	151
Income Tax Benefit (Expense) - Ending Balance	(1,735)
Accumulated Other Comprehensive Income (Loss) Net of Income Tax - Beginning Balance	3,146
Amortization of Prior service costs (credits)- Net of Income Tax	(238)	$ (238)
Accumulated Other Comprehensive Income (Loss) Net of Income Tax - Ending Balance	$ 2,908