Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 26, 2015	Dec. 27, 2014
Revenue	$ 3,167,634	$ 3,321,091	$ 3,184,790
Investment income	1,502	1,396	1,381
Costs and expenses:
Purchased transportation	2,415,663	2,551,343	2,461,143
Commissions to agents	264,205	270,260	250,780
Other operating costs, net of gains on asset sales/dispositions	29,702	31,618	25,771
Insurance and claims	57,280	48,754	46,280
Selling, general and administrative	143,239	149,704	150,250
Depreciation and amortization	35,796	29,102	27,575
Total costs and expenses	2,945,885	3,080,781	2,961,799
Operating income	223,251	241,706	224,372
Interest and debt expense	3,794	2,949	3,177
Income before income taxes	219,457	238,757	221,195
Income taxes	82,107	91,068	82,386
Net income	$ 137,350	$ 147,689	$ 138,809
Earnings per common share	$ 3.26	$ 3.38	$ 3.09
Diluted earnings per share	$ 3.25	$ 3.37	$ 3.07
Average number of shares outstanding:
Earnings per common share	42,112,000	43,664,000	44,956,000
Diluted earnings per share	42,236,000	43,813,000	45,169,000
Dividends per common share	$ 0.34	$ 0.30	$ 1.26