Organization and Significant Accounting Policies - Long-Lived Assets, Additional Information (Details) - USD ($)	12 Months Ended
Sep. 26, 2020	Sep. 28, 2019	Sep. 29, 2018
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment charge	$ 0		$ 0
Pet Segment
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment charge	$ 0	$ 2,500,000

The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of an intangible asset (excluding goodwill) to fair value.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16373-109275

Name:	us-gaap_ImpairmentOfIntangibleAssetsExcludingGoodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration