Consolidated Statements of Income (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Revenue	$ 3,184,790	$ 2,664,780	$ 2,770,799
Investment income	1,381	1,475	1,563
Costs and expenses:
Purchased transportation	2,461,143	2,046,927	2,130,323
Commissions to agents	250,780	211,355	218,122
Other operating costs, net of gains on asset dispositions	25,771	21,568	22,582
Insurance and claims	46,280	50,438	37,289
Selling, general and administrative	150,250	131,710	138,094
Depreciation and amortization	27,575	27,667	25,213
Total costs and expenses	2,961,799	2,489,665	2,571,623
Operating income	224,372	176,590	200,739
Interest and debt expense	3,177	3,211	3,110
Income from continuing operations before income taxes	221,195	173,379	197,629
Income taxes	82,386	64,457	71,063
Income from continuing operations	138,809	108,922	126,566
Discontinued operations:
Income from discontinued operations, net of income taxes		4,058	3,215
Gain on sale of discontinued operations, net of income taxes		33,029
Income from discontinued operations, net of income taxes		37,087	3,215
Net income	$ 138,809	$ 146,009	$ 129,781
Earnings per common share:
Income from continuing operations	$ 3.09	$ 2.37	$ 2.71
Income from discontinued operations		$ 0.81	$ 0.07
Earnings per common share	$ 3.09	$ 3.17	$ 2.78
Diluted earnings per share:
Income from continuing operations	$ 3.07	$ 2.36	$ 2.70
Income from discontinued operations		$ 0.80	$ 0.07
Diluted earnings per share	$ 3.07	$ 3.16	$ 2.77
Average number of shares outstanding:
Earnings per common share	44,956,000	46,039,000	46,698,000
Diluted earnings per share	45,169,000	46,210,000	46,877,000
Dividends per common share	$ 1.26	$ 0.35	$ 0.73