Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
OPERATING ACTIVITIES
Net income	$ 227,703	$ 255,213	$ 176,996
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of operating property and intangible assets	44,468	43,570	40,560
Non-cash interest charges	253	253	253
Provisions for losses on trade and other accounts receivable	9,831	7,415	7,439
Gains on sales/disposals of operating property	(1,016)	(979)	(774)
Deferred income taxes, net	4,767	2,115	(17,031)
Stock-based compensation	4,236	18,256	7,721
Changes in operating assets and liabilities:
Decrease (increase) in trade and other accounts receivable	81,415	(57,419)	(181,235)
Increase in other assets	(11,395)	(2,962)	(1,966)
(Decrease) increase in accounts payable	(42,138)	22,527	68,859
(Decrease) increase in other liabilities	(17,786)	8,367	22,085
Increase in insurance claims	7,502	1,545	16,056
NET CASH PROVIDED BY OPERATING ACTIVITIES	307,840	297,901	138,963
INVESTING ACTIVITIES
Net change in other short-term investments	(131)
Sales and maturities of investments	62,922	51,576	56,442
Purchases of investments	(65,922)	(54,041)	(58,504)
Purchases of operating property	(19,416)	(9,747)	(15,586)
Proceeds from sales of operating property	3,991	4,018	4,032
Consideration paid for acquisitions			(8,460)
NET CASH USED BY INVESTING ACTIVITIES	(18,556)	(8,194)	(22,076)
FINANCING ACTIVITIES
(Decrease) increase in cash overdraft	(1,461)	13,097	5,991
Dividends paid	(27,891)	(88,918)	(15,938)
Proceeds from exercises of stock options	1,056	1,435	3,183
Taxes paid in lieu of shares issued related to stock-based compensation plans	(8,456)	(3,938)	(881)
Purchases of common stock	(88,578)	(208,087)
Principal payments on finance lease obligations	(44,635)	(43,283)	(46,751)
Purchase of noncontrolling interest	(600)
Payment of contingent consideration		(985)
NET CASH USED BY FINANCING ACTIVITIES	(170,565)	(330,679)	(54,396)
Effect of exchange rate changes on cash and cash equivalents	1,060	(1,708)	1,028
Increase (decrease) in cash and cash equivalents	119,779	(42,680)	63,519
Cash and cash equivalents at beginning of period	199,736	242,416	178,897
Cash and cash equivalents at end of period	$ 319,515	$ 199,736	$ 242,416