Note 13 - Earnings Per Share - Reconciliation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Net income attributable to Generac Holdings Inc.		$ 156,359	$ 127,036	$ 270,217	$ 276,029
Redeemable noncontrolling interest redemption value adjustment		(13,645)	1,747	(25,592)	1,870
Net income attributable to common shareholders		$ 142,714	$ 128,783	$ 244,625	$ 277,899
Weighted average shares, basic (in shares)		63,662,510	62,605,166	63,607,711	62,533,725
Dilutive effect of stock compensation awards (in shares)	[1]	1,040,295	1,483,543	1,180,348	1,563,653
Dilutive effect of contingently issued shares (in shares)		10,943	0	10,943	0
Diluted shares (in shares)		64,713,748	64,088,709	64,799,002	64,097,378
Net income attributable to Generac Holdings Inc. per common share - basic: (in dollars per share)		$ 2.24	$ 2.06	$ 3.85	$ 4.44
Net income attributable to Generac Holdings Inc. per common share - diluted: (in dollars per share)		$ 2.21	$ 2.01	$ 3.78	$ 4.34

[1] Excludes approximately 17,000 stock options and restricted stock awards for the three months ended March 31, 2022 as the impact of such awards was anti-dilutive. There were no awards with an anti-dilutive impact for the three months ended March 31, 2021.