Segment Reporting (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Net sales	$ 1,093,720	$ 525,765	$ 2,093,978	$ 1,185,435
OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	864,654	367,812	1,680,904	900,169
Travel trailers and fifth-wheels
Disaggregation of Revenue [Line Items]
Net sales	527,614	212,518	1,030,630	519,626
Motorhomes
Disaggregation of Revenue [Line Items]
Net sales	67,253	24,713	129,846	62,800
Adjacent industries OEMs
Disaggregation of Revenue [Line Items]
Net sales	269,787	130,581	520,428	317,743
Aftermarket Segment
Disaggregation of Revenue [Line Items]
Net sales	229,066	157,953	413,074	285,266
Chassis, chassis parts and slide-out mechanisms | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	309,237	131,540	596,298	333,803
Windows and doors | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	256,722	109,696	506,642	265,727
Furniture and mattresses | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	168,804	57,662	324,048	144,842
Axles and suspension solutions | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	60,850	25,606	115,972	60,742
Other | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	69,041	43,308	137,944	95,055
U.S.
Disaggregation of Revenue [Line Items]
Net sales	991,078	481,707	1,900,129	1,080,522
U.S. | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	781,081	327,036	1,518,722	804,233
U.S. | Travel trailers and fifth-wheels
Disaggregation of Revenue [Line Items]
Net sales	508,810	204,977	995,352	508,659
U.S. | Motorhomes
Disaggregation of Revenue [Line Items]
Net sales	39,776	13,505	79,193	40,419
U.S. | Adjacent industries OEMs
Disaggregation of Revenue [Line Items]
Net sales	232,495	108,554	444,177	255,155
U.S. | Aftermarket Segment
Disaggregation of Revenue [Line Items]
Net sales	209,997	154,671	381,407	276,289
International
Disaggregation of Revenue [Line Items]
Net sales	102,642	44,058	193,849	104,913
International | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	83,573	40,776	162,182	95,936
International | Travel trailers and fifth-wheels
Disaggregation of Revenue [Line Items]
Net sales	18,804	7,541	35,278	10,967
International | Motorhomes
Disaggregation of Revenue [Line Items]
Net sales	27,477	11,208	50,653	22,381
International | Adjacent industries OEMs
Disaggregation of Revenue [Line Items]
Net sales	37,292	22,027	76,251	62,588
International | Aftermarket Segment
Disaggregation of Revenue [Line Items]
Net sales	$ 19,069	$ 3,282	$ 31,667	$ 8,977