Summary of Significant Accounting Polices (Tables)

12 Months Ended

Dec. 31, 2016

Accounting Policies [Abstract]

Schedule of Estimated Useful Life

For financial reporting purposes, assets are generally depreciated using the following estimated useful lives and salvage values:

	Lives	Salvage Values
Building and improvements	30 years	0%
Tractors	80 months	0%
Trailers	12 years	$1,000
Service and other equipment	3-10 years	0%

Schedule Of Basic and Diluted Earnings Per Share

The computation of basic and diluted earnings per share is shown below (in thousands, except per share amounts).

	Years Ended December 31,
	2016		2015		2014
Net income	$	79,129	$	123,714	$	98,650
Weighted average common shares outstanding	72,057		71,957		72,122
Dilutive effect of stock-based awards	336		599		616
Shares used in computing diluted earnings per share	72,393		72,556		72,738
Basic earnings per share	$	1.10	$	1.72	$	1.37
Diluted earnings per share	$	1.09	$	1.71	$	1.36