Major Product Categories and Percentage of Consolidated Net Sales (Detail) - 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, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Product Information [Line Items]
Total Net Sales	$ 462,057	$ 464,272	$ 471,439	$ 447,676	$ 543,711	$ 531,350	$ 514,831	$ 437,597	$ 527,477	$ 491,697	$ 486,021	$ 358,120	$ 1,845,444	$ 2,027,489	$ 1,863,315
Sales Revenue, Net
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													$ (13,070)	$ (11,679)	$ (12,300)
Commercial Trailer Products
Product Information [Line Items]
Total Net Sales													1,506,110	1,582,241	1,380,623
Diversified Products
Product Information [Line Items]
Total Net Sales													352,404	456,927	494,992
New Trailers
Product Information [Line Items]
Total Net Sales													$ 1,551,136	$ 1,692,229	$ 1,493,825
New Trailers | Sales Revenue, Net
Product Information [Line Items]
Percentage of consolidated net sales													84.10%	83.50%	80.20%
New Trailers | Corporate and Eliminations
Product Information [Line Items]
Total Net Sales													$ (89)	$ 0	$ 0
New Trailers | Commercial Trailer Products
Product Information [Line Items]
Total Net Sales													1,421,586	1,474,201	1,267,610
New Trailers | Diversified Products
Product Information [Line Items]
Total Net Sales													129,639	218,028	226,215
Used Trailers
Product Information [Line Items]
Total Net Sales													$ 15,174	$ 35,580	$ 45,115
Used Trailers | Sales Revenue, Net
Product Information [Line Items]
Percentage of consolidated net sales													0.80%	1.80%	2.40%
Used Trailers | Corporate and Eliminations
Product Information [Line Items]
Total Net Sales													$ 0	$ 0	$ 0
Used Trailers | Commercial Trailer Products
Product Information [Line Items]
Total Net Sales													11,998	31,022	41,027
Used Trailers | Diversified Products
Product Information [Line Items]
Total Net Sales													3,176	4,558	4,088
Components, parts and service
Product Information [Line Items]
Total Net Sales													$ 154,755	$ 168,550	$ 170,589
Components, parts and service | Sales Revenue, Net
Product Information [Line Items]
Percentage of consolidated net sales													8.40%	8.30%	9.20%
Components, parts and service | Corporate and Eliminations
Product Information [Line Items]
Total Net Sales													$ (12,955)	$ (11,628)	$ (12,300)
Components, parts and service | Commercial Trailer Products
Product Information [Line Items]
Total Net Sales													56,191	60,482	55,429
Components, parts and service | Diversified Products
Product Information [Line Items]
Total Net Sales													111,519	119,696	127,460
Equipment and other
Product Information [Line Items]
Total Net Sales													$ 124,379	$ 131,130	$ 153,786
Equipment and other | Sales Revenue, Net
Product Information [Line Items]
Percentage of consolidated net sales													6.70%	6.40%	8.20%
Equipment and other | Corporate and Eliminations
Product Information [Line Items]
Total Net Sales													$ (26)	$ (51)	$ 0
Equipment and other | Commercial Trailer Products
Product Information [Line Items]
Total Net Sales													16,335	16,536	16,557
Equipment and other | Diversified Products
Product Information [Line Items]
Total Net Sales													$ 108,070	$ 114,645	$ 137,229