Product Warranties - Schedule of Activity Associated with Warranty Obligations (Details) - USD ($) $ in Millions	6 Months Ended
Jul. 04, 2026	Jun. 28, 2025
Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$ 48.2	$ 17.5
Accruals for warranties issued	17.5	6.8
Settlements	(16.3)	(6.7)
Accruals included in acquisition / divestiture	0.6	(0.4)
Balance at end of period	$ 50.0	$ 17.2

Standard Product Warranty Accrual, Increase (Decrease) Due To (Acquisitions) Divestitures

No definition available.

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Namespace Prefix:	hni_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Standard Product Warranty Accrual, Settlements, Increase (Decrease)

+ References

No definition available.

+ Details

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Namespace Prefix:	hni_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount as of the balance sheet date of the aggregate standard product warranty liability. Does not include the balance for the extended product warranty liability.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Subparagraph (c)(5)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482425/460-10-50-8

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482425/460-10-50-8

+ Details

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

- Definition

Amount of increase in the standard product warranty accrual from warranties issued. Excludes extended product warranties.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration