Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015
OPERATING ACTIVITIES
Net income	$ 97,776	$ 109,834
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of operating property	26,109	21,253
Non-cash interest charges	175	164
Provisions for losses on trade and other accounts receivable	4,076	4,667
Gains on sales/disposals of operating property	(3,221)	(278)
Deferred income taxes, net	8,925	957
Stock-based compensation	2,718	4,939
Changes in operating assets and liabilities:
Decrease in trade and other accounts receivable	50,957	23,262
Decrease in other assets	3,820	5,830
Decrease in accounts payable	(25,074)	(14,563)
Decrease in other liabilities	(5,436)	(3,849)
Increase (decrease) in insurance claims	10,472	(4,132)
NET CASH PROVIDED BY OPERATING ACTIVITIES	171,297	148,084
INVESTING ACTIVITIES
Sales and maturities of investments	30,580	29,545
Purchases of investments	(31,938)	(34,751)
Purchases of operating property	(17,833)	(3,798)
Proceeds from sales of operating property	8,622	1,567
NET CASH USED BY INVESTING ACTIVITIES	(10,569)	(7,437)
FINANCING ACTIVITIES
Decrease in cash overdraft	(7,884)	(4,963)
Dividends paid	(10,572)	(54,467)
Payment for debt issue costs	(1,048)
Proceeds from exercises of stock options	1,440	1,076
Taxes paid in lieu of shares issued related to stock-based compensation plans	(1,715)	(2,176)
Excess tax benefits from stock-based awards	343	652
Purchases of common stock	(50,516)	(107,214)
Principal payments on capital lease obligations	(35,147)	(26,972)
NET CASH USED BY FINANCING ACTIVITIES	(105,099)	(194,064)
Effect of exchange rate changes on cash and cash equivalents	656	(1,628)
Increase (decrease) in cash and cash equivalents	56,285	(55,045)
Cash and cash equivalents at beginning of period	114,520	163,944
Cash and cash equivalents at end of period	$ 170,805	$ 108,899