Note 16 - Commitments and Contingencies (Details Textual) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Amount Financed by Dealers	$ 56.1	$ 49.6

Amount financed by dealers to purchase goods from the entity.

No definition available.

Name:	gnrc_AmountFinancedByDealers
Namespace Prefix:	gnrc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant