Summary of Significant Accounting Policies - Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Jan. 01, 2022	Jan. 02, 2021	Dec. 28, 2019
Numerator:
Numerator for both basic and diluted EPS attributable to HNI Corporation net income	$ 59,814	$ 41,917	$ 110,505
Denominators:
Denominator for basic EPS weighted- average common shares outstanding (in shares)	43,438	42,689	43,101
Potentially dilutive shares from stock-based compensation plans (in shares)	526	267	394
Denominator for diluted EPS (in shares)	43,964	42,956	43,495
Earnings per share - basic (in dollars per share)	$ 1.38	$ 0.98	$ 2.56
Earnings per share - diluted (in dollars per share)	$ 1.36	$ 0.98	$ 2.54
Stock Compensation Plan
Denominators:
Common stock equivalents excluded because their inclusion would be anti-dilutive (in shares)	1,606	3,110	2,131