Description of Business and Summary of Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Summary of Property and Equipment, Estimated Useful Lives

Depreciation is computed using the straight-line method based on the following service lives:

	Years
Structures	20 to 25
Tractors	6 to 10
Trailers	10 to 14
Other revenue equipment	7 to 14
Technology equipment and software	3 to 5
Other	3 to 10

Schedule of Property and Equipment

At December 31, property and equipment consisted of the following (in thousands):

	2018		2017
Land	$	100,157	$	81,487
Structures		321,283		268,723
Tractors		476,875		398,652
Trailers		354,490		305,540
Other revenue equipment		83,571		77,691
Technology equipment and software		110,954		93,754
Other		74,011		64,147
Total property and equipment, at cost	$	1,521,341	$	1,289,994

Summary of Risk Retention Amounts Per Occurrence

Risk retention amounts per occurrence during the three years ended December 31, 2018, were as follows:

Workers’ compensation	$	1,000,000
Bodily injury and property damage		2,000,000
Employee medical and hospitalization		400,000
Cargo loss and damage		250,000

Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with Customers

Effect of Adoption of Standard on Previously Reported Financial Data

The below tables reflect the effect of the adoption of this standard on the previously reported financial data.

Condensed Consolidated Balance Sheet impact:

	As of December 31, 2017								As of December 31, 2016
		As adjusted		As originally reported		Effect of change			As adjusted		As originally reported		Effect of change
	(in thousands)
Accounts receivable		$	170,278	$	170,610	$	(332	)	$	134,926	$	135,083	$	(157	)
Total current assets			203,249		203,581		(332	)		166,322		166,479		(157	)
Total assets			967,315		967,647		(332	)		800,213		800,370		(157	)
Accounts payable			57,438		57,717		(279	)		45,018		45,149		(131	)
Total current liabilities			166,926		167,205		(279	)		144,813		144,944		(131	)
Retained earnings			339,500		339,553		(53	)		248,371		248,397		(26	)
Total stockholders’ equity			582,494		582,547		(53	)		483,052		483,078		(26	)
Total liabilities and stockholders’ equity			967,315		967,647		(332	)		800,213		800,370		(157	)

Condensed Consolidated Statement of Operations Impact:

	For the quarter ended December 31, 2017							For the year ended December 31, 2017
		As adjusted		As originally reported		Effect of change			As adjusted		As originally reported		Effect of change
	(in thousands, except per share data)
Operating revenue		$	360,196	$	353,251	$	6,945		$	1,404,703	$	1,378,510	$	26,193
Purchased transportation			28,185		21,270		6,915			107,702		81,482		26,220
Total operating expenses			337,268		330,353		6,915			1,309,993		1,283,773		26,220
Operating income			22,928		22,898		30			94,710		94,737		(27	)
Net income			47,789		47,759		30			91,129		91,156		(27	)
Basic Earnings Per Share			1.87		1.87		—			3.57		3.57		—
Diluted Earnings Per Share			1.82		1.82		—			3.49		3.49		—

	For the year ended December 31, 2016
		As adjusted		As originally reported		Effect of change
	(in thousands, except per share data)
Operating revenue		$	1,250,391	$	1,218,481	$	31,910
Purchased transportation			88,239		56,329		31,910
Total operating expenses			1,171,255		1,139,345		31,910
Operating income			79,136		79,136		—
Net income			48,024		48,024		—
Basic Earnings Per Share			1.92		1.92		—
Diluted Earnings Per Share			1.87		1.87		—

Condensed Consolidated Statement of Cash Flows impact:

	For the year ended December 31, 2017										For the year ended December 31, 2016
		As adjusted			As originally reported			Effect of change				As adjusted		As originally reported		Effect of change
	(in thousands)
Net income		$	91,129		$	91,156		$	(27	)		$	48,024	$	48,024	$	—
Changes in operating assets and liabilities, net			(7,143	)		(7,170	)		27				2,592		2,592		—
Net cash provided by operating activities			157,846			157,846			—				146,426		146,426		—
Net decrease in cash and cash equivalents			3,181			3,181			—				1,415		1,415		—