Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2017	Mar. 26, 2016
OPERATING ACTIVITIES
Net income	$ 32,383	$ 29,184
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of operating property	9,934	8,438
Non-cash interest charges	64	54
Provisions for losses on trade and other accounts receivable	1,857	1,494
Gains on sales/disposals of operating property	(463)	(874)
Deferred income taxes, net	(709)	2,682
Stock-based compensation	994	1,100
Changes in operating assets and liabilities:
Decrease in trade and other accounts receivable	16,427	67,842
(Increase) decrease in other assets	(174)	9,783
Decrease in accounts payable	(15,424)	(51,674)
Increase in other liabilities	13,357	1,724
Increase in insurance claims	3,702	2,285
NET CASH PROVIDED BY OPERATING ACTIVITIES	61,948	72,038
INVESTING ACTIVITIES
Sales and maturities of investments	23,155	10,636
Purchases of investments	(23,678)	(11,190)
Purchases of operating property	(4,978)	(828)
Proceeds from sales of operating property	1,665	2,273
NET CASH (USED) PROVIDED BY INVESTING ACTIVITIES	(3,836)	891
FINANCING ACTIVITIES
Decrease in cash overdraft	(6,878)	(5,536)
Dividends paid	(3,770)	(3,396)
Proceeds from exercises of stock options	1,717	105
Taxes paid in lieu of shares issued related to stock-based compensation plans	(339)	(1,527)
Excess tax benefits from stock-based awards		149
Purchases of common stock		(10,228)
Principal payments on capital lease obligations	(12,408)	(11,315)
NET CASH USED BY FINANCING ACTIVITIES	(21,678)	(31,748)
Effect of exchange rate changes on cash and cash equivalents	137	583
Increase in cash and cash equivalents	36,571	41,764
Cash and cash equivalents at beginning of period	178,897	114,520
Cash and cash equivalents at end of period	$ 215,468	$ 156,284