Major Product Categories and Percentage of Consolidated Net Sales (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Product Information [Line Items]
Total net sales	$ 2,027,489	$ 1,863,315	$ 1,635,686
Sales Revenue, Net [Member]
Product Information [Line Items]
Percentage of consolidated net sales	100.00%	100.00%	100.00%
Corporate and Eliminations
Product Information [Line Items]
Total net sales	$ (77,203)	$ (87,167)	$ (86,909)
Commercial Trailer Products
Product Information [Line Items]
Total net sales	1,509,380	1,294,164	1,082,456
Diversified Products
Product Information [Line Items]
Total net sales	428,021	466,238	458,653
Retail
Product Information [Line Items]
Total net sales	167,291	190,080	181,486
New Trailers
Product Information [Line Items]
Total net sales	$ 1,692,229	$ 1,493,825	$ 1,246,923
New Trailers | Sales Revenue, Net [Member]
Product Information [Line Items]
Percentage of consolidated net sales	83.50%	73.70%	66.90%
New Trailers | Corporate and Eliminations
Product Information [Line Items]
Total net sales	$ (60,467)	$ (72,862)	$ (71,888)
New Trailers | Commercial Trailer Products
Product Information [Line Items]
Total net sales	1,467,029	1,250,264	1,031,004
New Trailers | Diversified Products
Product Information [Line Items]
Total net sales	218,028	227,382	204,812
New Trailers | Retail
Product Information [Line Items]
Total net sales	67,639	89,041	82,995
Used Trailers
Product Information [Line Items]
Total net sales	$ 35,580	$ 45,115	$ 49,415
Used Trailers | Sales Revenue, Net [Member]
Product Information [Line Items]
Percentage of consolidated net sales	1.80%	2.20%	2.70%
Used Trailers | Corporate and Eliminations
Product Information [Line Items]
Total net sales	$ (2,562)	$ 0	$ (5)
Used Trailers | Commercial Trailer Products
Product Information [Line Items]
Total net sales	19,962	23,576	33,443
Used Trailers | Diversified Products
Product Information [Line Items]
Total net sales	4,558	4,593	3,158
Used Trailers | Retail
Product Information [Line Items]
Total net sales	13,622	16,946	12,819
Components, parts and service
Product Information [Line Items]
Total net sales	$ 168,550	$ 170,589	$ 180,326
Components, parts and service | Sales Revenue, Net [Member]
Product Information [Line Items]
Percentage of consolidated net sales	8.30%	8.40%	9.70%
Components, parts and service | Corporate and Eliminations
Product Information [Line Items]
Total net sales	$ (14,116)	$ (14,183)	$ (14,811)
Components, parts and service | Commercial Trailer Products
Product Information [Line Items]
Total net sales	6,300	3,475	7,420
Components, parts and service | Diversified Products
Product Information [Line Items]
Total net sales	93,251	100,764	106,312
Components, parts and service | Retail
Product Information [Line Items]
Total net sales	83,115	80,533	81,405
Equipment and other
Product Information [Line Items]
Total net sales	$ 131,130	$ 153,786	$ 159,022
Equipment and other | Sales Revenue, Net [Member]
Product Information [Line Items]
Percentage of consolidated net sales	6.40%	15.70%	20.70%
Equipment and other | Corporate and Eliminations
Product Information [Line Items]
Total net sales	$ (58)	$ (122)	$ (205)
Equipment and other | Commercial Trailer Products
Product Information [Line Items]
Total net sales	16,089	16,849	10,589
Equipment and other | Diversified Products
Product Information [Line Items]
Total net sales	112,184	133,499	144,371
Equipment and other | Retail
Product Information [Line Items]
Total net sales	$ 2,915	$ 3,560	$ 4,267