Income Taxes - Significant Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 30, 2017	Dec. 31, 2016
Deferred tax assets:
Allowance for doubtful accounts	$ 7,416	$ 10,552
Accrued employee benefits	6,472	35,020
Restructuring reserves	4,646	14,885
Workers’ compensation, general and fleet liabilities	42,958	61,118
Deferred income	162	470
Deferred financing costs	1,744	5,379
Postretirement benefit obligations	23,350	51,618
Net operating loss carryforwards	86,246	162,511
Other accrued expenses	9,819	30,429
Total gross deferred tax assets	182,813	371,982
Less valuation allowance	(28,962)	(24,274)
Total net deferred tax assets	153,851	347,708
Deferred tax liabilities:
Property and equipment	(92,092)	(216,556)
Inventories	(29,802)	(41,765)
Intangibles	(273,774)	(435,817)
Total deferred tax liabilities	(395,668)	(694,138)
Net deferred tax liability	$ (241,817)	$ (346,430)