INCOME TAXES (Schedule of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 27, 2015	Dec. 28, 2014
Deferred tax liabilities:
PP&E and identified intangible assets	$ 151,761	$ 126,537
Inventories	97,743	48,365
Insurance claims and losses	39,800	36,953
Other	15,054	26,801
Total deferred tax liabilities	304,358	238,656
Deferred tax assets:
Net operating losses	4,297	5,842
Foreign net operating losses	16,595	7,873
Credit carry forwards	2,638	2,916
Allowance for doubtful accounts	4,382	4,261
Accrued liabilities	56,753	52,772
Workers compensation	41,217	43,309
Pension and other postretirement benefits	22,559	26,049
Other	31,956	30,612
Total deferred tax assets	180,397	173,634
Valuation allowance	(7,921)	(9,150)
Net deferred tax assets	172,476	164,484
Net deferred tax liabilities	$ 131,882	$ 74,172