Income Taxes - Temporary Differences and Carryforwards that Comprised Deferred Income Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 29, 2019
Income Tax Disclosure [Abstract]
Acquisition related contingent consideration	$ 107,769	$ 110,036
Operating lease liabilities	34,632	27,346
Deferred revenue	27,882	24,936
Deferred compensation	26,269	26,788
Accrued liabilities	22,341	19,266
Postretirement benefits	14,726	13,250
Pension	11,055	14,124
Transactional costs	4,451	4,857
Charitable contribution carryover	3,236	6,622
Net operating loss carryforwards	1,628	2,012
Financing lease agreements	1,618	2,432
Other	10,138	3,022
Deferred income tax assets	265,745	254,691
Less: Valuation allowance for deferred tax assets	5,325	7,190
Net deferred income tax asset	260,420	247,501
Intangible assets	(182,585)	(151,940)
Depreciation	(159,359)	(147,140)
Right-of-use assets - operating leases	(33,316)	(26,997)
Inventory	(13,709)	(12,631)
Prepaid expenses	(6,319)	(7,627)
Patronage dividend	(4,555)	(3,009)
Investment in Piedmont	0	(23,287)
Deferred income tax liabilities	(399,843)	(372,631)
Net deferred income tax liability	$ (139,423)	$ (125,130)