Inventories (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Inventory [Line Items]
Raw materials and components	$ 102,405	$ 83,834
Finished goods	95,831	54,000
Work in progress	28,198	29,123
Aftermarket parts	5,998	6,448
Used trailers	4,283	7,330
Total, Inventories	$ 236,715	$ 180,735