Summary of Significant Accounting Polices (Tables)

12 Months Ended

Dec. 31, 2015

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,
	2015		2014		2013
Net income	$	123,714	$	98,650	$	86,785
Weighted average common shares outstanding	71,957		72,122		72,866
Dilutive effect of stock-based awards	599		616		562
Shares used in computing diluted earnings per share	72,556		72,738		73,428
Basic earnings per share	$	1.72	$	1.37	$	1.19
Diluted earnings per share	$	1.71	$	1.36	$	1.18