Summary of Significant Accounting Policies and Basis of Presentation - Summary of Changes in SpartanNash's Self-Insurance Liability (Detail) - USD ($) $ in Thousands	12 Months Ended
Jan. 02, 2021	Dec. 28, 2019	Dec. 29, 2018
Payables And Accruals [Abstract]
Balance at beginning of year	$ 16,780	$ 14,291	$ 15,155
Expenses	62,999	69,253	49,532
Acquisitions		1,894
Claim payments, net of employee contributions	(63,042)	(68,658)	(50,396)
Balance at end of year	$ 16,737	$ 16,780	$ 14,291

Carrying amount (including both current and noncurrent portions) of accrued known and estimated losses incurred as of the balance sheet date for which no insurance coverage exists, and for which a claim has been made or is probable of being asserted, typically arising from workmen's compensation-type of incidents and personal injury to nonemployees from accidents on the entity's property.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.24)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Name:	us-gaap_SelfInsuranceReserve
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant