Segment Reporting (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Net sales	$ 629,068	$ 684,455	$ 1,221,240	$ 1,334,947
OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	553,368	616,918	1,085,148	1,217,097
Travel trailers and fifth-wheels
Disaggregation of Revenue [Line Items]
Net sales	343,051	399,464	659,922	804,421
Motorhomes
Disaggregation of Revenue [Line Items]
Net sales	41,357	49,071	86,357	101,986
Adjacent industries OEMs
Disaggregation of Revenue [Line Items]
Net sales	168,960	168,383	338,869	310,690
Aftermarket Segment
Disaggregation of Revenue [Line Items]
Net sales	75,700	67,537	136,092	117,850
Chassis, chassis parts and slide-out mechanisms | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	213,209	247,811	417,592	500,514
Windows and doors | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	156,064	169,372	307,983	318,892
Furniture and mattresses | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	93,562	105,278	184,919	210,796
Axles and suspension solutions | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	33,957	33,148	66,192	66,753
Other | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	56,576	61,309	108,462	120,142
U.S.
Disaggregation of Revenue [Line Items]
Net sales	597,592	658,373	1,156,148	1,286,275
U.S. | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	524,722	593,944	1,026,746	1,174,500
U.S. | Travel trailers and fifth-wheels
Disaggregation of Revenue [Line Items]
Net sales	340,025	397,511	653,392	801,253
U.S. | Motorhomes
Disaggregation of Revenue [Line Items]
Net sales	28,943	37,553	60,864	80,959
U.S. | Adjacent industries OEMs
Disaggregation of Revenue [Line Items]
Net sales	155,754	158,880	312,490	292,288
U.S. | Aftermarket Segment
Disaggregation of Revenue [Line Items]
Net sales	72,870	64,429	129,402	111,775
International
Disaggregation of Revenue [Line Items]
Net sales	31,476	26,082	65,092	48,672
International | OEM Segment
Disaggregation of Revenue [Line Items]
Net sales	28,646	22,974	58,402	42,597
International | Travel trailers and fifth-wheels
Disaggregation of Revenue [Line Items]
Net sales	3,026	1,953	6,530	3,168
International | Motorhomes
Disaggregation of Revenue [Line Items]
Net sales	12,414	11,518	25,493	21,027
International | Adjacent industries OEMs
Disaggregation of Revenue [Line Items]
Net sales	13,206	9,503	26,379	18,402
International | Aftermarket Segment
Disaggregation of Revenue [Line Items]
Net sales	$ 2,830	$ 3,108	$ 6,690	$ 6,075