Reportable Segment Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Net sales
Total net sales	$ 413,126	$ 362,408	$ 737,355	$ 640,090
Income (Loss) from operations	30,452	8,568	45,308	14,017
Reconciling items to income before income taxes
Interest expense	(6,577)	(5,441)	(14,112)	(6,174)
Other, net	(333)	(56)	1,905	(60)
Income before income taxes	23,542	3,071	33,101	7,783
External customers
Net sales
Total net sales	413,126	362,408	737,355	640,090
Intersegment sales
Net sales
Total net sales	0	0	0	0
Commercial Trailer Products
Net sales
Total net sales	265,835	280,730	463,910	524,110
Income (Loss) from operations	14,555	13,735	19,873	19,922
Commercial Trailer Products | External customers
Net sales
Total net sales	244,060	263,350	428,148	496,910
Commercial Trailer Products | Intersegment sales
Net sales
Total net sales	21,775	17,380	35,762	27,200
Diversified Products
Net sales
Total net sales	135,467	72,121	247,483	103,711
Income (Loss) from operations	19,262	9,285	32,782	14,669
Diversified Products | External customers
Net sales
Total net sales	121,360	61,054	220,947	80,056
Diversified Products | Intersegment sales
Net sales
Total net sales	14,107	11,067	26,536	23,655
Retail
Net sales
Total net sales	48,136	38,171	88,979	63,291
Income (Loss) from operations	1,261	1,027	2,134	952
Retail | External customers
Net sales
Total net sales	47,706	38,004	88,260	63,124
Retail | Intersegment sales
Net sales
Total net sales	430	167	719	167
Corporate and Eliminations
Net sales
Total net sales	(36,312)	(28,614)	(63,017)	(51,022)
Income (Loss) from operations	(4,626)	(15,479)	(9,481)	(21,526)
Corporate and Eliminations | External customers
Net sales
Total net sales	0	0	0	0
Corporate and Eliminations | Intersegment sales
Net sales
Total net sales	$ (36,312)	$ (28,614)	$ (63,017)	$ (51,022)