Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
OPERATING ACTIVITIES
Net income	$ 186,913	$ 112,313
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of operating property and intangible assets	32,520	29,961
Non-cash interest charges	190	189
Provisions for losses on trade and other accounts receivable	5,360	5,643
Gains on sales/disposals of operating property	(1,025)	(900)
Deferred income taxes, net	7,459	(708)
Stock-based compensation	13,003	3,660
Changes in operating assets and liabilities:
Increase in trade and other accounts receivable	(60,785)	(89,504)
Increase in other assets	(9,779)	(8,671)
Increase in accounts payable	22,121	53,290
Increase in other liabilities	3,245	12,980
Increase in insurance claims	4,983	14,011
NET CASH PROVIDED BY OPERATING ACTIVITIES	204,205	132,264
INVESTING ACTIVITIES
Sales and maturities of investments	34,259	42,917
Purchases of investments	(36,296)	(44,423)
Purchases of operating property	(7,325)	(8,800)
Proceeds from sales of operating property	3,542	3,594
Consideration paid for acquisitions		(8,199)
NET CASH USED BY INVESTING ACTIVITIES	(5,820)	(14,911)
FINANCING ACTIVITIES
Decrease in cash overdraft	(2,483)	(2,398)
Dividends paid	(82,261)	(11,739)
Proceeds from exercises of stock options	1,397	2,531
Taxes paid in lieu of shares issued related to stock-based compensation plans	(3,936)	(371)
Purchases of common stock	(105,488)
Principal payments on capital lease obligations	(32,663)	(35,662)
Payment of contingent consideration	(985)
NET CASH USED BY FINANCING ACTIVITIES	(226,419)	(47,639)
Effect of exchange rate changes on cash and cash equivalents	(408)	1,130
(Decrease) increase in cash and cash equivalents	(28,442)	70,844
Cash and cash equivalents at beginning of period	242,416	178,897
Cash and cash equivalents at end of period	$ 213,974	$ 249,741