Segment Reporting (Schedule of Net Sales by Segment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information
Net sales	$ 2,796,166	$ 2,371,482	$ 2,475,807
OEM Segment
Segment Reporting Information
Net sales	2,167,911	2,091,901	2,242,616
Travel Trailer and Fifth Wheels
Segment Reporting Information
Net sales	1,321,567	1,276,718	1,440,730
Motorhomes
Segment Reporting Information
Net sales	158,096	155,623	187,297
OEMs Adjacent Industries
Segment Reporting Information
Net sales	688,248	659,560	614,589
Aftermarket Segment
Segment Reporting Information
Net sales	628,255	279,581	233,191
U.S.
Segment Reporting Information
Net sales	2,559,353	2,225,712	2,371,750
U.S. | OEM Segment
Segment Reporting Information
Net sales	1,952,241	1,962,330	2,149,162
U.S. | Travel Trailer and Fifth Wheels
Segment Reporting Information
Net sales	1,288,209	1,264,404	1,431,574
U.S. | Motorhomes
Segment Reporting Information
Net sales	100,950	110,405	143,488
U.S. | OEMs Adjacent Industries
Segment Reporting Information
Net sales	563,082	587,521	574,100
U.S. | Aftermarket Segment
Segment Reporting Information
Net sales	607,112	263,382	222,588
Int'l
Segment Reporting Information
Net sales	236,813	145,770	104,057
Int'l | OEM Segment
Segment Reporting Information
Net sales	215,670	129,571	93,454
Int'l | Travel Trailer and Fifth Wheels
Segment Reporting Information
Net sales	33,358	12,314	9,156
Int'l | Motorhomes
Segment Reporting Information
Net sales	57,146	45,218	43,809
Int'l | OEMs Adjacent Industries
Segment Reporting Information
Net sales	125,166	72,039	40,489
Int'l | Aftermarket Segment
Segment Reporting Information
Net sales	$ 21,143	$ 16,199	$ 10,603