Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019
OPERATING ACTIVITIES
Net income	$ 127,035	$ 177,655
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of operating property and intangible assets	34,212	33,045
Non-cash interest charges	222	190
Provisions for losses on trade and other accounts receivable	7,206	6,942
Gains on sales/disposals of operating property	(2,295)	(1,188)
Impairment of intangible and other assets	2,582
Deferred income taxes, net	4,758	7,151
Stock-based compensation	2,691	4,470
Changes in operating assets and liabilities:
(Increase) decrease in trade and other accounts receivable	(62,492)	84,607
Increase in other assets	(13,492)	(21,129)
Increase (decrease) in accounts payable	66,815	(28,692)
Increase (decrease) in other liabilities	14,050	(16,076)
Increase in insurance claims	4,256	13,739
NET CASH PROVIDED BY OPERATING ACTIVITIES	185,548	260,714
INVESTING ACTIVITIES
Net changes in other short-term investments	131
Sales and maturities of investments	18,795	56,467
Purchases of investments	(21,102)	(58,829)
Purchases of operating property	(25,426)	(15,199)
Proceeds from sales of operating property	6,623	3,621
Consideration paid for acquisition	(2,766)
NET CASH USED BY INVESTING ACTIVITIES	(23,745)	(13,940)
FINANCING ACTIVITIES
Decrease in cash overdraft	(6,419)	(10,714)
Dividends paid	(101,442)	(20,589)
Payment for debt issue costs	(959)
Proceeds from exercises of stock options	676	629
Taxes paid in lieu of shares issued related to stock-based compensation plans	(3,326)	(8,449)
Purchases of common stock	(115,962)	(88,578)
Principal payments on finance lease obligations	(33,036)	(34,141)
Purchase of noncontrolling interest		(600)
NET CASH USED BY FINANCING ACTIVITIES	(260,468)	(162,442)
Effect of exchange rate changes on cash and cash equivalents	(2,296)	366
(Decrease) increase in cash and cash equivalents	(100,961)	84,698
Cash and cash equivalents at beginning of period	319,515	199,736
Cash and cash equivalents at end of period	$ 218,554	$ 284,434