Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 28, 2019	Sep. 29, 2018
Numerator:
Numerator for both basic and diluted EPS attributable to HNI Corporation net income	$ 46,078	$ 39,907	$ 62,910	$ 61,014
Denominators:
Denominator for basic EPS weighted-average common shares outstanding (in shares)	42,899	43,823	43,217	43,616
Potentially dilutive shares from stock-based compensation plans (in shares)	287	856	403	733
Denominator for diluted EPS (in shares)	43,186	44,679	43,620	44,349
Earnings per share - basic (in dollars per share)	$ 1.07	$ 0.91	$ 1.46	$ 1.40
Earnings per share - diluted (in dollars per share)	$ 1.07	$ 0.89	$ 1.44	$ 1.38