Segment Reporting (Schedule of Net Sales by Product) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information
Total net sales	$ 2,796,166	$ 2,371,482	$ 2,475,807
OEM Segment
Segment Reporting Information
Total net sales	2,167,911	2,091,901	2,242,616
Aftermarket Segment
Segment Reporting Information
Total net sales	628,255	279,581	233,191
Chassis, Chassis Parts and Slide-out Mechanisms | OEM Segment
Segment Reporting Information
Total net sales	815,706	796,434	908,065
Windows and Doors | OEM Segment
Segment Reporting Information
Total net sales	620,372	585,464	615,644
Furniture and Mattresses | OEM Segment
Segment Reporting Information
Total net sales	351,107	342,691	380,514
Axles and Suspension Solutions | OEM Segment
Segment Reporting Information
Total net sales	145,989	129,471	122,897
Other Products | OEM Segment
Segment Reporting Information
Total net sales	$ 234,737	$ 237,841	$ 215,496