Inventories - Summary of Inventories (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Inventory [Line Items]
Total inventories, net	$ 104,598	$ 75,004
New Equipment Sales [Member]
Inventory [Line Items]
Total inventories, net	84,603	55,704
Used Equipment Sales [Member]
Inventory [Line Items]
Total inventories, net	1,980	2,421
Parts, Supplies and Other [Member]
Inventory [Line Items]
Total inventories, net	$ 18,015	$ 16,879