Earnings Per Share - Earnings Per Share Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 30, 2024	Apr. 01, 2023
Numerator:
Numerator for both basic and diluted EPS attributable to HNI Corporation net income	$ 17.7	$ 1.6
Denominators:
Denominator for basic EPS weighted-average common shares outstanding (in shares)	47.1	41.5
Potentially dilutive shares from stock-based compensation plans (in shares)	1.0	0.5
Denominator for diluted EPS (in shares)	48.1	42.1
Earnings per share - basic (in dollars per share)	$ 0.38	$ 0.04
Earnings per share - diluted (in dollars per share)	$ 0.37	$ 0.04