Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net sales		$ 559,515	$ 455,839	$ 1,452,098	$ 1,181,199
Costs of goods sold		361,630	299,608	937,968	783,247
Gross profit		197,885	156,231	514,130	397,952
Operating expenses:
Selling and service		46,536	43,463	135,270	124,940
Research and development		13,653	10,850	38,122	31,690
General and administrative		25,499	22,128	75,613	64,508
Amortization of intangibles		5,678	7,242	16,792	21,554
Total operating expenses		91,366	83,683	265,797	242,692
Income from operations		106,519	72,548	248,333	155,260
Other (expense) income:
Interest expense		(9,824)	(10,672)	(30,939)	(32,353)
Investment income		382	14	1,095	57
Loss on extinguishment of debt	[1]			(1,332)
Other, net		(483)	(1,710)	(2,764)	(3,525)
Total other expense, net		(9,925)	(12,368)	(33,940)	(35,821)
Income before provision for income taxes		96,594	60,180	214,393	119,439
Provision for income taxes		20,072	20,404	49,870	42,105
Net income		76,522	39,776	164,523	77,334
Net income attributable to noncontrolling interests		746	341	1,841	433
Net income attributable to Generac Holdings Inc.		$ 75,776	$ 39,435	$ 162,682	$ 76,901
Net income attributable to common shareholders per common share - basic: (in dollars per share)		$ 1.12	$ 0.64	$ 2.36	$ 1.25
Weighted average common shares outstanding - basic: (in shares)		61,579,564	61,758,190	61,659,817	62,094,807
Net income attributable to common shareholders per common share - diluted: (in dollars per share)		$ 1.11	$ 0.63	$ 2.34	$ 1.24
Weighted average common shares outstanding - diluted: (in shares)		62,220,298	62,316,788	62,266,140	62,703,269
Comprehensive income attributable to Generac Holdings Inc.		$ 80,768	$ 42,939	$ 173,355	$ 90,867

[1] Represents the non-cash write-off of original issue discount and deferred financing costs due to a voluntary prepayment of Term Loan debt.