Segment Reporting (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Net sales	$ 586,221	$ 604,244	$ 1,807,461	$ 1,939,191
OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	511,550	539,978	1,596,698	1,757,075
Travel trailers and fifth-wheels
Disaggregation of Revenue [Line Items]
Net sales	314,056	338,830	973,978	1,143,251
Motorhomes
Disaggregation of Revenue [Line Items]
Net sales	34,810	43,244	121,167	145,230
Adjacent industries OEMs
Disaggregation of Revenue [Line Items]
Net sales	162,684	157,904	501,553	468,594
Aftermarket Segment
Disaggregation of Revenue [Line Items]
Net sales	74,671	64,266	210,763	182,116
Chassis, chassis parts and slide-out mechanisms | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	193,354	214,272	610,946	714,786
Windows and doors | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	145,360	157,336	453,343	476,228
Furniture and mattresses | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	79,512	88,411	264,431	299,207
Axles and suspension solutions | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	31,405	30,148	97,597	96,901
Other | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	61,919	49,811	170,381	169,953
U.S.
Disaggregation of Revenue [Line Items]
Net sales	550,938	577,523	1,707,086	1,863,798
U.S. | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	480,654	515,787	1,507,400	1,690,287
U.S. | Travel trailers and fifth-wheels
Disaggregation of Revenue [Line Items]
Net sales	311,446	335,842	964,838	1,137,095
U.S. | Motorhomes
Disaggregation of Revenue [Line Items]
Net sales	25,944	32,929	86,808	113,888
U.S. | Adjacent industries OEMs
Disaggregation of Revenue [Line Items]
Net sales	143,264	147,016	455,754	439,304
U.S. | Aftermarket Segment
Disaggregation of Revenue [Line Items]
Net sales	70,284	61,736	199,686	173,511
International
Disaggregation of Revenue [Line Items]
Net sales	35,283	26,721	100,375	75,393
International | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	30,896	24,191	89,298	66,788
International | Travel trailers and fifth-wheels
Disaggregation of Revenue [Line Items]
Net sales	2,610	2,988	9,140	6,156
International | Motorhomes
Disaggregation of Revenue [Line Items]
Net sales	8,866	10,315	34,359	31,342
International | Adjacent industries OEMs
Disaggregation of Revenue [Line Items]
Net sales	19,420	10,888	45,799	29,290
International | Aftermarket Segment
Disaggregation of Revenue [Line Items]
Net sales	$ 4,387	$ 2,530	$ 11,077	$ 8,605