Summary of Significant Accounting Policies (Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Numerator:
Numerator for both basic and diluted EPS attributable to HNI Corporation net income	$ 110,505	$ 93,377	$ 89,795
Denominators:
Denominator for basic EPS weighted- average common shares outstanding (in shares)	43,101,000	43,639,000	43,839,000
Potentially dilutive shares from stock-based compensation plans (shares)	394,000	689,000	1,001,000
Denominator for diluted EPS (shares)	43,495,000	44,328,000	44,840,000
Earnings per share - basic (in dollars per share)	$ 2.56	$ 2.14	$ 2.05
Earnings per share - diluted (in dollars per share)	$ 2.54	$ 2.11	$ 2.00
Stock Compensation Plan
Denominators:
Common stock equivalents excluded because their inclusion would be anti-dilutive (in shares)	2,131,000	1,508,000	809,000