Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Numerator:
Numerator for both basic and diluted EPS attributable to HNI Corporation net income	$ 30,688	$ 46,078	$ 19,349	$ 62,910
Denominators:
Denominator for basic EPS weighted-average common shares outstanding (in shares)	42,684	42,899	42,651	43,217
Potentially dilutive shares from stock-based compensation plans (in shares)	326	287	254	403
Denominator for diluted EPS (in shares)	43,010	43,186	42,905	43,620
Earnings per share - basic (in dollars per share)	$ 0.72	$ 1.07	$ 0.45	$ 1.46
Earnings per share - diluted (in dollars per share)	$ 0.71	$ 1.07	$ 0.45	$ 1.44