Description of Business and Summary of Accounting Policies - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	$ 1,101,946	$ 995,514
Land [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	69,115	57,506
Structures [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	196,843	181,769
Tractors [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	350,737	314,326
Trailers [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	279,393	256,494
Other Revenue Equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	38,050	36,828
Technology Equipment and Software [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	80,342	72,707
Other [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	$ 87,466	$ 75,884