Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2020	Dec. 28, 2019	Dec. 29, 2018
Net income attributable to Landstar System, Inc. and subsidiary	$ 192,106	$ 227,720	$ 255,281
Other comprehensive income (loss):
Unrealized holding gains (losses) on available-for-sale investments, net of tax expense (benefit) of $463, $561, $(206)	1,688	2,050	(786)
Foreign currency translation (losses) gains	(1,475)	1,613	(1,927)
Other comprehensive income (loss)	213	3,663	(2,713)
Comprehensive income attributable to Landstar System, Inc. and subsidiary	$ 192,319	$ 231,383	$ 252,568