Earnings Per Share - Schedule of Earnings Per Share Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2022	Oct. 02, 2021	Oct. 01, 2022	Oct. 02, 2021
Numerator:
Numerator for both basic and diluted EPS attributable to HNI Corporation net income	$ 63.1	$ 19.2	$ 107.6	$ 51.6
Denominators:
Denominator for basic EPS weighted-average common shares outstanding (in shares)	41.3	43.8	41.8	43.6
Potentially dilutive shares from stock-based compensation plans (in shares)	0.5	0.6	0.5	0.5
Denominator for diluted EPS (in shares)	41.8	44.3	42.3	44.0
Earnings per share - basic (in dollars per share)	$ 1.53	$ 0.44	$ 2.57	$ 1.18
Earnings per share - diluted (in dollars per share)	$ 1.51	$ 0.43	$ 2.54	$ 1.17