Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Dec. 26, 2015
Revenue	$ 3,646,364	$ 3,167,634	$ 3,321,091
Investment income	2,498	1,502	1,396
Costs and expenses:
Purchased transportation	2,805,109	2,415,663	2,551,343
Commissions to agents	297,410	264,205	270,260
Other operating costs, net of gains on asset sales/dispositions	28,687	29,702	31,618
Insurance and claims	62,545	57,280	48,754
Selling, general and administrative	170,583	143,239	149,704
Depreciation and amortization	40,560	35,796	29,102
Total costs and expenses	3,404,894	2,945,885	3,080,781
Operating income	243,968	223,251	241,706
Interest and debt expense	3,166	3,794	2,949
Income before income taxes	240,802	219,457	238,757
Income taxes	63,806	82,107	91,068
Net income	176,996	137,350	147,689
Less: Net loss attributable to noncontrolling interest	(92)
Net income attributable to Landstar System, Inc. and subsidiary	$ 177,088	$ 137,350	$ 147,689
Earnings per common share attributable to Landstar System, Inc. and subsidiary	$ 4.22	$ 3.26	$ 3.38
Diluted earnings per share attributable to Landstar System, Inc. and subsidiary	$ 4.21	$ 3.25	$ 3.37
Average number of shares outstanding:
Earnings per common share	41,938,000	42,112,000	43,664,000
Diluted earnings per share	42,024,000	42,236,000	43,813,000
Dividends per common share	$ 1.88	$ 0.34	$ 0.30