Reportable Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Net Sales
Total Net Sales	$ 447,676	$ 437,597
Income (Loss) from operations	48,185	27,263
Assets	975,670	984,972	$ 949,670
External Customers
Net Sales
Total Net Sales	447,676	437,597
Intersegment Sales
Net Sales
Total Net Sales	0	0
Commercial Trailer Products
Net Sales
Total Net Sales	354,848	314,504
Income (Loss) from operations	52,060	22,770
Assets	332,516	354,975
Commercial Trailer Products | External Customers
Net Sales
Total Net Sales	337,195	293,742
Commercial Trailer Products | Intersegment Sales
Net Sales
Total Net Sales	17,653	20,762
Diversified Products
Net Sales
Total Net Sales	79,424	103,992
Income (Loss) from operations	6,622	10,611
Assets	378,160	404,888
Diversified Products | External Customers
Net Sales
Total Net Sales	76,638	101,041
Diversified Products | Intersegment Sales
Net Sales
Total Net Sales	2,786	2,951
Retail
Net Sales
Total Net Sales	34,037	43,140
Income (Loss) from operations	(149)	1,126
Assets	67,032	68,285
Retail | External Customers
Net Sales
Total Net Sales	33,843	42,814
Retail | Intersegment Sales
Net Sales
Total Net Sales	194	326
Corporate and Eliminations
Net Sales
Total Net Sales	(20,633)	(24,039)
Income (Loss) from operations	(10,348)	(7,244)
Assets	197,963	156,825
Corporate and Eliminations | External Customers
Net Sales
Total Net Sales	0	0
Corporate and Eliminations | Intersegment Sales
Net Sales
Total Net Sales	$ (20,633)	$ (24,039)