Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Excess Purchase Price over Predecessor Basis [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Parent [Member]	Noncontrolling Interest [Member]	Total
Balance (in shares) at Dec. 31, 2020	72,024,329		(9,173,731)
Balance at Dec. 31, 2020	$ 721	$ 525,541	$ (332,164)	$ (202,116)	$ 1,432,565	$ (34,254)	$ 1,390,293	$ (89)	$ 1,390,204
Unrealized gain (loss) on interest rate swaps, net of tax	0	0	0	0	0	12,243	12,243	0	12,243
Foreign currency translation adjustment	$ 0	0	0	0	0	(15,572)	(15,572)	(5)	(15,577)
Common stock issued under equity incentive plans, net of shares withheld for employee taxes and strike price (in shares)	228,651
Common stock issued under equity incentive plans, net of shares withheld for employee taxes and strike price	$ 2	4,931	0	0	0	0	4,933	0	4,933
Net share settlement of restricted stock awards	0	0	$ (26,317)	0	0	0	(26,317)	0	(26,317)
Net share settlement of restricted stock awards (in shares)			(78,366)
Share-based compensation	0	12,421	$ 0	0	0	0	12,421	0	12,421
Redemption value adjustment	0	0	0	0	1,870	0	1,870	0	1,870
Net income attributable to Generac Holdings Inc.	$ 0	0	$ 0	0	276,029	0	276,029		276,029
Net income								132
Net income									276,161
Balance (in shares) at Jun. 30, 2021	72,252,980		(9,252,097)
Balance at Jun. 30, 2021	$ 723	542,893	$ (358,481)	(202,116)	1,710,464	(37,583)	1,655,900	38	1,655,938
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax, Total	$ 0	0	$ 0	0	0	12,243	12,243	0	12,243
Balance (in shares) at Mar. 31, 2021	72,205,746		(9,251,818)
Balance at Mar. 31, 2021	$ 723	534,303	$ (358,362)	(202,116)	1,581,681	(31,499)	1,524,730	(161)	1,524,569
Unrealized gain (loss) on interest rate swaps, net of tax	0	0	0	0	0	(2,752)	(2,752)	0	(2,752)
Foreign currency translation adjustment	$ 0	0	0	0	0	(3,332)	(3,332)	(2)	(3,334)
Common stock issued under equity incentive plans, net of shares withheld for employee taxes and strike price (in shares)	47,234
Common stock issued under equity incentive plans, net of shares withheld for employee taxes and strike price	$ 0	1,617	0	0	0	0	1,617	0	1,617
Net share settlement of restricted stock awards	0	0	$ (119)	0	0	0	(119)	0	(119)
Net share settlement of restricted stock awards (in shares)			(279)
Share-based compensation	0	6,973	$ 0	0	0	0	6,973	0	6,973
Redemption value adjustment	0	0	0	0	1,747	0	1,747	0	1,747
Net income attributable to Generac Holdings Inc.	$ 0	0	$ 0	0	127,036	0	127,036		127,036
Net income								201
Net income									127,237
Balance (in shares) at Jun. 30, 2021	72,252,980		(9,252,097)
Balance at Jun. 30, 2021	$ 723	542,893	$ (358,481)	(202,116)	1,710,464	(37,583)	1,655,900	38	1,655,938
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax, Total	$ 0	0	$ 0	0	0	(2,752)	(2,752)	0	(2,752)
Balance (in shares) at Dec. 31, 2021	72,386,017		(8,667,031)
Balance at Dec. 31, 2021	$ 725	952,939	$ (448,976)	(202,116)	1,965,957	(54,755)	2,213,774	313	2,214,087
Unrealized gain (loss) on interest rate swaps, net of tax	0	0	0	0	0	25,857	25,857	0	25,857
Foreign currency translation adjustment	$ 0	0	0	0	0	(53,941)	(53,941)	(74)	(54,015)
Common stock issued under equity incentive plans, net of shares withheld for employee taxes and strike price (in shares)	202,571
Common stock issued under equity incentive plans, net of shares withheld for employee taxes and strike price	$ 2	(1,682)	0	0	0	0	(1,680)	0	(1,680)
Net share settlement of restricted stock awards	0	0	$ (26,318)	0	0	0	(26,318)	0	(26,318)
Net share settlement of restricted stock awards (in shares)			(88,420)
Share-based compensation	0	16,562	$ 0	0	0	0	16,562	0	16,562
Redemption value adjustment	0	0	0	0	(25,592)	0	(25,592)	0	(25,592)
Net income attributable to Generac Holdings Inc.	$ 0	0	$ 0	0	270,217	0	270,217		270,217
Net income								644
Net income									270,861
Balance (in shares) at Jun. 30, 2022	72,588,588		(8,755,451)
Balance at Jun. 30, 2022	$ 727	967,819	$ (475,294)	(202,116)	2,210,582	(82,839)	2,418,879	883	2,419,762
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax, Total	$ 0	0	$ 0	0	0	25,857	25,857	0	25,857
Balance (in shares) at Mar. 31, 2022	72,589,905		(8,740,863)
Balance at Mar. 31, 2022	$ 727	959,890	$ (471,833)	(202,116)	2,067,868	(46,402)	2,308,134	478	2,308,612
Unrealized gain (loss) on interest rate swaps, net of tax	0	0	0	0	0	7,129	7,129	0	7,129
Foreign currency translation adjustment	$ 0	0	0	0	0	(43,566)	(43,566)	(256)	(43,822)
Common stock issued under equity incentive plans, net of shares withheld for employee taxes and strike price (in shares)	(1,317)
Common stock issued under equity incentive plans, net of shares withheld for employee taxes and strike price	$ 0	194	0	0	0	0	194	0	194
Net share settlement of restricted stock awards	0	0	$ (3,461)	0	0	0	(3,461)	0	(3,461)
Net share settlement of restricted stock awards (in shares)			(14,588)
Share-based compensation	0	7,735	$ 0	0	0	0	7,735	0	7,735
Redemption value adjustment	0	0	0	0	(13,645)	0	(13,645)	0	(13,645)
Net income attributable to Generac Holdings Inc.	$ 0	0	$ 0	0	156,359	0	156,359		156,359
Net income								661
Net income									157,020
Balance (in shares) at Jun. 30, 2022	72,588,588		(8,755,451)
Balance at Jun. 30, 2022	$ 727	967,819	$ (475,294)	(202,116)	2,210,582	(82,839)	2,418,879	883	2,419,762
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax, Total	$ 0	$ 0	$ 0	$ 0	$ 0	$ 7,129	$ 7,129	$ 0	$ 7,129