Segment Reporting (Schedule of Net Sales by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information
Net sales	$ 564,021	$ 586,221	$ 629,068	$ 592,172	$ 536,616	$ 604,244	$ 684,455	$ 650,492	$ 2,371,482	$ 2,475,807	$ 2,147,770
OEM Segment
Segment Reporting Information
Net sales									2,091,901	2,242,616	1,976,623
Travel Trailer and Fifth Wheels
Segment Reporting Information
Net sales									1,276,718	1,440,730	1,405,983
Motorhomes
Segment Reporting Information
Net sales									155,623	187,297	159,417
OEMs Adjacent Industries
Segment Reporting Information
Net sales									659,560	614,589	411,223
Aftermarket Segment
Segment Reporting Information
Net sales									279,581	233,191	171,147
U.S.
Segment Reporting Information
Net sales									2,225,712	2,371,750	2,101,530
U.S. | OEM Segment
Segment Reporting Information
Net sales									1,962,330	2,149,162	1,940,893
U.S. | Travel Trailer and Fifth Wheels
Segment Reporting Information
Net sales									1,264,404	1,431,574	1,403,079
U.S. | Motorhomes
Segment Reporting Information
Net sales									110,405	143,488	138,895
U.S. | OEMs Adjacent Industries
Segment Reporting Information
Net sales									587,521	574,100	398,919
U.S. | Aftermarket Segment
Segment Reporting Information
Net sales									263,382	222,588	160,637
Int'l
Segment Reporting Information
Net sales									145,770	104,057	46,240
Int'l | OEM Segment
Segment Reporting Information
Net sales									129,571	93,454	35,730
Int'l | Travel Trailer and Fifth Wheels
Segment Reporting Information
Net sales									12,314	9,156	2,904
Int'l | Motorhomes
Segment Reporting Information
Net sales									45,218	43,809	20,522
Int'l | OEMs Adjacent Industries
Segment Reporting Information
Net sales									72,039	40,489	12,304
Int'l | Aftermarket Segment
Segment Reporting Information
Net sales									$ 16,199	$ 10,603	$ 10,510