Employee Pension Benefits - Schedule of Changes in Components of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 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			(777)
Accumulated Other Comprehensive Income (Loss) Before Tax - Ending Balance	$ 4,255		4,255
Income Tax Benefit (Expense) - Beginning Balance			(1,886)
Amortization of Prior service costs (credits)- Tax Effect			301
Income Tax Benefit (Expense) - Ending Balance	(1,585)		(1,585)
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)	(476)	$ (476)
Accumulated Other Comprehensive Income (Loss) Net of Income Tax - Ending Balance	$ 2,670		$ 2,670