Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Dec. 26, 2015
Net income attributable to Landstar System, Inc. and subsidiary	$ 177,088	$ 137,350	$ 147,689
Other comprehensive income (loss):
Unrealized holding (losses) gains on available-for-sale investments, net of tax (benefit) expense of $(41), $13, ($109)	(73)	23	(199)
Foreign currency translation gains (losses)		376	(2,104)
Other comprehensive (loss) income	(73)	399	(2,303)
Comprehensive income attributable to Landstar System, Inc. and subsidiary	$ 177,015	$ 137,749	$ 145,386