Accumulated Other Comprehensive Income (Loss) and Shareholders' Equity - Schedule of Reclassification from Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 28, 2024	Dec. 30, 2023	Dec. 31, 2022
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense, net	$ 27.2	$ 25.5	$ 8.8
Selling and administrative expenses	820.7	813.2	723.4
Income tax expense	(39.8)	(15.6)	(22.5)
Gain on sale of subsidiary	0.0	0.0	50.4
Numerator for both basic and diluted EPS attributable to HNI Corporation net income	139.5	49.2	123.9
Reclassifications from Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Numerator for both basic and diluted EPS attributable to HNI Corporation net income	0.2	0.0	3.1
Reclassifications from Accumulated Other Comprehensive Income (Loss) | Derivative financial instruments | Interest rate swap
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense, net	0.5	0.2	0.1
Income tax expense	(0.1)	(0.1)	(0.0)
Reclassifications from Accumulated Other Comprehensive Income (Loss) | Unrealized gains (losses) on debt securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Selling and administrative expenses	(0.1)	(0.1)	0.0
Income tax expense	(0.0)	(0.0)	(0.0)
Reclassifications from Accumulated Other Comprehensive Income (Loss) | Pension and post-retirement liabilities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Selling and administrative expenses	(0.1)	(0.1)	(0.3)
Income tax expense	(0.0)	(0.0)	0.1
Reclassifications from Accumulated Other Comprehensive Income (Loss) | Foreign currency translation
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gain on sale of subsidiary	$ 0.0	$ 0.0	$ 3.3