Segment Reporting (Schedule of Net Sales by Product) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information
Total net sales	$ 402,899	$ 412,370	$ 440,831	$ 422,798	$ 334,228	$ 345,296	$ 362,085	$ 361,457	$ 1,678,898	$ 1,403,066	$ 1,190,782
OEM Segment
Segment Reporting Information
Total net sales									1,548,091	1,300,060	1,127,026
Aftermarket Segment
Segment Reporting Information
Total net sales									130,807	103,006	63,756
Chassis, Chassis Parts and Slide-out Mechanisms | OEM Segment
Segment Reporting Information
Total net sales									743,160	664,542	593,756
Windows and Doors | OEM Segment
Segment Reporting Information
Total net sales									335,717	301,171	258,915
Furniture and Mattresses | OEM Segment
Segment Reporting Information
Total net sales									245,596	161,840	132,356
Axles and Suspension Solutions | OEM Segment
Segment Reporting Information
Total net sales									115,538	108,464	88,909
Other Products | OEM Segment
Segment Reporting Information
Total net sales									$ 108,080	$ 64,043	$ 53,090