Segments Information - Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segments Information
Revenue	$ 1,064,769	$ 1,058,661
Intersegment Eliminations
Segments Information
Revenue	(10,812)	(10,344)
Good Sam services and plans
Segments Information
Revenue	46,966	44,825
Good Sam services and plans | Intersegment Eliminations
Segments Information
Revenue	(1,332)	(1,353)
New vehicles
Segments Information
Revenue	529,577	579,510
New vehicles | Intersegment Eliminations
Segments Information
Revenue	(1,172)	(1,164)
Used vehicles
Segments Information
Revenue	180,008	172,091
Used vehicles | Intersegment Eliminations
Segments Information
Revenue	(597)	(492)
Products, service and other
Segments Information
Revenue	204,876	164,152
Products, service and other | Intersegment Eliminations
Segments Information
Revenue	(5,322)	(4,816)
Finance and insurance, net
Segments Information
Revenue	91,891	89,100
Finance and insurance, net | Intersegment Eliminations
Segments Information
Revenue	(2,389)	(2,519)
Good Sam Club
Segments Information
Revenue	11,451	8,983
Good Sam services and plans | Operating Segments
Segments Information
Revenue	48,298	46,178
Good Sam services and plans | Good Sam services and plans | Operating Segments
Segments Information
Revenue	48,298	46,178
RV and Outdoor Retail
Segments Information
Revenue	1,017,803	1,013,836
RV and Outdoor Retail | Operating Segments
Segments Information
Revenue	1,027,283	1,022,827
RV and Outdoor Retail | New vehicles
Segments Information
Revenue	529,577	579,510
RV and Outdoor Retail | New vehicles | Operating Segments
Segments Information
Revenue	530,749	580,674
RV and Outdoor Retail | Used vehicles
Segments Information
Revenue	180,008	172,091
RV and Outdoor Retail | Used vehicles | Operating Segments
Segments Information
Revenue	180,605	172,583
RV and Outdoor Retail | Products, service and other
Segments Information
Revenue	204,876	164,152
RV and Outdoor Retail | Products, service and other | Operating Segments
Segments Information
Revenue	210,198	168,968
RV and Outdoor Retail | Finance and insurance, net
Segments Information
Revenue	91,891	89,100
RV and Outdoor Retail | Finance and insurance, net | Operating Segments
Segments Information
Revenue	94,280	91,619
RV and Outdoor Retail | Good Sam Club
Segments Information
Revenue	11,451	8,983
RV and Outdoor Retail | Good Sam Club | Operating Segments
Segments Information
Revenue	$ 11,451	$ 8,983