Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018
OPERATING ACTIVITIES
Net income	$ 124,400	$ 119,965
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of operating property and intangible assets	22,350	21,766
Non-cash interest charges	126	126
Provisions for losses on trade and other accounts receivable	4,194	4,297
Gains on sales/disposals of operating property	(1,219)	(988)
Deferred income taxes, net	5,060	5,585
Stock-based compensation	3,368	8,102
Changes in operating assets and liabilities:
Decrease (increase) in trade and other accounts receivable	89,820	(48,651)
Increase in other assets	(22,808)	(16,537)
(Decrease) increase in accounts payable	(28,565)	20,161
Decrease in other liabilities	(14,315)	(4,488)
Increase in insurance claims	1,665	3,691
NET CASH PROVIDED BY OPERATING ACTIVITIES	184,076	113,029
INVESTING ACTIVITIES
Sales and maturities of investments	41,345	18,399
Purchases of investments	(42,812)	(19,653)
Purchases of operating property	(9,224)	(4,121)
Proceeds from sales of operating property	3,219	2,939
NET CASH USED BY INVESTING ACTIVITIES	(7,472)	(2,436)
FINANCING ACTIVITIES
(Decrease) increase in cash overdraft	(11,719)	3,123
Dividends paid	(13,257)	(75,481)
Proceeds from exercises of stock options	343	1,039
Taxes paid in lieu of shares issued related to stock-based compensation plans	(8,438)	(2,812)
Purchases of common stock	(69,729)	(105,488)
Principal payments on finance lease obligations	(23,658)	(22,768)
Purchase of noncontrolling interest	(600)
Payment of contingent consideration		(985)
NET CASH USED BY FINANCING ACTIVITIES	(127,058)	(203,372)
Effect of exchange rate changes on cash and cash equivalents	930	(996)
Increase (decrease) in cash and cash equivalents	50,476	(93,775)
Cash and cash equivalents at beginning of period	199,736	242,416
Cash and cash equivalents at end of period	$ 250,212	$ 148,641