Segment Reporting (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Net sales	$ 592,172	$ 650,492
OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	531,780	600,179
Travel trailers and fifth-wheels
Disaggregation of Revenue [Line Items]
Net sales	316,871	404,957
Motorhomes
Disaggregation of Revenue [Line Items]
Net sales	45,000	52,915
Adjacent industries OEMs
Disaggregation of Revenue [Line Items]
Net sales	169,909	142,307
Aftermarket Segment
Disaggregation of Revenue [Line Items]
Net sales	60,392	50,313
Chassis, chassis parts and slide-out mechanisms | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	204,383	252,702
Windows and doors | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	151,919	149,520
Furniture and mattresses | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	91,357	105,518
Axles and suspension solutions | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	32,235	33,605
Other | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	51,886	58,834
U.S.
Disaggregation of Revenue [Line Items]
Net sales	558,556	627,902
U.S. | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	502,024	580,556
U.S. | Travel trailers and fifth-wheels
Disaggregation of Revenue [Line Items]
Net sales	313,367	403,742
U.S. | Motorhomes
Disaggregation of Revenue [Line Items]
Net sales	31,921	43,406
U.S. | Adjacent industries OEMs
Disaggregation of Revenue [Line Items]
Net sales	156,736	133,408
U.S. | Aftermarket Segment
Disaggregation of Revenue [Line Items]
Net sales	56,532	47,346
International
Disaggregation of Revenue [Line Items]
Net sales	33,616	22,590
International | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	29,756	19,623
International | Travel trailers and fifth-wheels
Disaggregation of Revenue [Line Items]
Net sales	3,504	1,215
International | Motorhomes
Disaggregation of Revenue [Line Items]
Net sales	13,079	9,509
International | Adjacent industries OEMs
Disaggregation of Revenue [Line Items]
Net sales	13,173	8,899
International | Aftermarket Segment
Disaggregation of Revenue [Line Items]
Net sales	$ 3,860	$ 2,967