Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 26, 2021	Jun. 27, 2020	Jun. 26, 2021	Jun. 27, 2020
Revenue	$ 1,570,718	$ 823,514	$ 2,858,252	$ 1,751,080
Investment income	748	835	1,432	2,002
Costs and expenses:
Purchased transportation	1,228,241	635,133	2,226,526	1,344,390
Commissions to agents	121,693	75,266	221,702	150,642
Other operating costs, net of gains on asset sales/dispositions	8,903	7,368	16,545	15,674
Insurance and claims	24,124	19,751	45,629	44,708
Selling, general and administrative	54,114	40,601	99,522	85,928
Depreciation and amortization	12,143	11,467	24,244	22,972
Impairment of intangible and other assets	0	2,582	0	2,582
Total costs and expenses	1,449,218	792,168	2,634,168	1,666,896
Operating income	122,248	32,181	225,516	86,186
Interest and debt expense	967	976	2,009	1,928
Income before income taxes	121,281	31,205	223,507	84,258
Income taxes	28,987	6,951	53,973	19,109
Net income	$ 92,294	$ 24,254	$ 169,534	$ 65,149
Diluted earnings per share	$ 2.40	$ 0.63	$ 4.41	$ 1.68
Average diluted shares outstanding	38,402,000	38,379,000	38,403,000	38,816,000
Dividends per common share	$ 0.210	$ 0.185	$ 0.420	$ 0.370