Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 27, 2020	Dec. 29, 2019
Deferred tax assets:
Accounts receivable	$ 32,688	$ 26,973
Inventories	14,038	10,020
Loss and credit carryforwards	221,598	35,509
Operating leases	23,147	15,378
Operating expenses	32,912	23,124
Pension	7,905	6,206
Other compensation	33,718	27,633
Postretirement benefits	7,932	7,053
Interest rate hedge	4,996	5,202
Tax sharing agreement	2,219	3,096
Deferred revenue	8,298	5,591
Other	11,992	10,637
Gross deferred tax assets	401,443	176,422
Deferred tax liabilities:
Depreciation and amortization of long-lived assets	181,227	13,361
Equity method investment	21,328	17,674
Operating leases	20,056	11,936
Foreign exchange	7,280	58
Prepaid expenses	3,565	2,597
Other	10,993	7,741
Gross deferred tax liabilities	244,449	53,367
Valuation allowance	(174,185)	(33,260)
Net deferred income taxes	$ (17,191)
Net deferred income taxes		$ 89,795