Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Net income attributable to Landstar System, Inc. and subsidiary	$ 227,720	$ 255,281	$ 177,088
Other comprehensive income (loss):
Unrealized holding gains (losses) on available-for-sale investments, net of tax expense (benefit) of $561, $(206), $(41)	2,050	(786)	(73)
Foreign currency translation gains (losses)	1,613	(1,927)
Other comprehensive income (loss)	3,663	(2,713)	(73)
Comprehensive income attributable to Landstar System, Inc. and subsidiary	$ 231,383	$ 252,568	$ 177,015