Condensed Consolidated Statements of Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 27, 2025	Sep. 28, 2024	Sep. 27, 2025	Sep. 28, 2024
Income Statement [Abstract]
Net sales	$ 683.8	$ 672.2	$ 1,950.6	$ 1,883.9
Cost of sales	395.7	393.4	1,138.0	1,110.9
Gross profit	288.1	278.8	812.6	773.0
Selling and administrative expenses	222.7	208.4	645.7	617.3
Restructuring, impairment, and loss on divestiture	0.8	1.6	9.7	3.7
Operating income	64.6	68.9	157.2	151.9
Interest expense, net	7.2	7.1	18.9	22.1
Income before income taxes	57.4	61.8	138.3	129.8
Income taxes	16.2	14.3	34.9	28.6
Net income	41.2	47.5	103.4	101.2
Less: Net income (loss) attributable to non-controlling interest	0.0	0.0	0.0	0.0
Net income attributable to HNI Corporation	$ 41.2	$ 47.5	$ 103.4	$ 101.2
Average number of common shares outstanding – basic (in shares)	45.8	47.7	46.3	47.3
Net income attributable to HNI Corporation per common share – basic (in dollars per share)	$ 0.90	$ 1.00	$ 2.23	$ 2.14
Average number of common shares outstanding – diluted (in shares)	46.7	48.7	47.3	48.4
Net income attributable to HNI Corporation per common share – diluted (in dollars per share)	$ 0.88	$ 0.98	$ 2.19	$ 2.09
Foreign currency translation adjustments	$ 0.1	$ 0.0	$ 6.3	$ (0.1)
Change in unrealized gains (losses) on marketable securities, net of tax	0.0	0.3	0.2	0.3
Change in pension and post-retirement liability, net of tax	0.0	0.0	2.0	0.0
Change in derivative financial instruments, net of tax	0.2	(1.8)	(0.5)	0.0
Other comprehensive income (loss), net of tax	0.3	(1.4)	8.1	0.2
Comprehensive income	41.5	46.1	111.5	101.4
Less: Comprehensive income (loss) attributable to non-controlling interest	0.0	0.0	0.0	0.0
Comprehensive income attributable to HNI Corporation	$ 41.5	$ 46.1	$ 111.5	$ 101.4