Segment Reporting (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Net sales	$ 659,670	$ 592,172
OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	532,357	531,780
Travel trailers and fifth-wheels
Disaggregation of Revenue [Line Items]
Net sales	307,108	316,871
Motorhomes
Disaggregation of Revenue [Line Items]
Net sales	38,087	45,000
Adjacent industries OEMs
Disaggregation of Revenue [Line Items]
Net sales	187,162	169,909
Aftermarket Segment
Disaggregation of Revenue [Line Items]
Net sales	127,313	60,392
Chassis, chassis parts and slide-out mechanisms | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	202,263	204,383
Windows and doors | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	156,031	151,919
Furniture and mattresses | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	87,180	91,357
Axles and suspension solutions | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	35,136	32,235
Other | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	51,747	51,886
U.S.
Disaggregation of Revenue [Line Items]
Net sales	598,815	558,556
U.S. | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	477,197	502,024
U.S. | Travel trailers and fifth-wheels
Disaggregation of Revenue [Line Items]
Net sales	303,682	313,367
U.S. | Motorhomes
Disaggregation of Revenue [Line Items]
Net sales	26,914	31,921
U.S. | Adjacent industries OEMs
Disaggregation of Revenue [Line Items]
Net sales	146,601	156,736
U.S. | Aftermarket Segment
Disaggregation of Revenue [Line Items]
Net sales	121,618	56,532
International
Disaggregation of Revenue [Line Items]
Net sales	60,855	33,616
International | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	55,160	29,756
International | Travel trailers and fifth-wheels
Disaggregation of Revenue [Line Items]
Net sales	3,426	3,504
International | Motorhomes
Disaggregation of Revenue [Line Items]
Net sales	11,173	13,079
International | Adjacent industries OEMs
Disaggregation of Revenue [Line Items]
Net sales	40,561	13,173
International | Aftermarket Segment
Disaggregation of Revenue [Line Items]
Net sales	$ 5,695	$ 3,860