Major Product Categories and Percentage of Consolidated Net Sales (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Product Information [Line Items]
Net external sales	$ 358,120	$ 324,229
Percentage of consolidated net sales	100.00%	100.00%
Commercial Trailer Products
Product Information [Line Items]
Net external sales	206,997	183,986
Diversified Products
Product Information [Line Items]
Net external sales	105,764	99,689
Retail
Product Information [Line Items]
Net external sales	45,359	40,554
New Trailers
Product Information [Line Items]
Net external sales	268,118	235,467
Percentage of consolidated net sales	74.90%	72.60%
New Trailers | Commercial Trailer Products
Product Information [Line Items]
Net external sales	193,000	175,003
New Trailers | Diversified Products
Product Information [Line Items]
Net external sales	54,847	43,521
New Trailers | Retail
Product Information [Line Items]
Net external sales	20,271	16,943
Used Trailers
Product Information [Line Items]
Net external sales	16,065	8,647
Percentage of consolidated net sales	4.50%	2.70%
Used Trailers | Commercial Trailer Products
Product Information [Line Items]
Net external sales	11,248	5,050
Used Trailers | Diversified Products
Product Information [Line Items]
Net external sales	1,178	949
Used Trailers | Retail
Product Information [Line Items]
Net external sales	3,639	2,648
Components, parts and service
Product Information [Line Items]
Net external sales	41,698	41,285
Percentage of consolidated net sales	11.60%	12.70%
Components, parts and service | Commercial Trailer Products
Product Information [Line Items]
Net external sales	580	2,705
Components, parts and service | Diversified Products
Product Information [Line Items]
Net external sales	20,420	18,901
Components, parts and service | Retail
Product Information [Line Items]
Net external sales	20,698	19,679
Equipment and other
Product Information [Line Items]
Net external sales	32,239	38,830
Percentage of consolidated net sales	9.00%	12.00%
Equipment and other | Commercial Trailer Products
Product Information [Line Items]
Net external sales	2,169	1,228
Equipment and other | Diversified Products
Product Information [Line Items]
Net external sales	29,319	36,318
Equipment and other | Retail
Product Information [Line Items]
Net external sales	$ 751	$ 1,284