Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 26, 2011
OPERATING ACTIVITIES
Net income	$ 26,847	$ 20,557
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of operating property and intangible assets	6,740	6,399
Non-cash interest charges	54	55
Provisions for losses on trade and other accounts receivable	923	1,226
Losses (gains) on sales/disposals of operating property, net	(213)	63
Deferred income taxes, net	5,131	(1,068)
Stock-based compensation	1,525	1,205
Changes in operating assets and liabilities:
Increase in trade and other accounts receivable	(17,509)	(45,364)
Decrease in other assets	3,458	5,870
Increase in accounts payable	2,544	23,407
Increase (decrease) in other liabilities	(3,046)	1,283
Increase (decrease) in insurance claims	(6,542)	2,971
NET CASH PROVIDED BY OPERATING ACTIVITIES	19,912	16,604
INVESTING ACTIVITIES
Sales and maturities of investments	8,912	23,870
Purchases of investments	(26,214)	(20,650)
Purchases of operating property	(1,026)	(1,808)
Proceeds from sales of operating property	1,073	300
NET CASH PROVIDED (USED) BY INVESTING ACTIVITIES	(17,255)	1,712
FINANCING ACTIVITIES
Decrease in cash overdraft	(3,154)	(1,470)
Dividends paid	(2,574)	(2,394)
Proceeds from exercises of stock options	723	70
Excess (shortfall) tax effect on stock option exercises	864	(181)
Principal payments on long-term debt and capital lease obligations	(26,006)	(6,023)
Purchase of noncontrolling interest		(8,000)
NET CASH USED BY FINANCING ACTIVITIES	(30,147)	(17,998)
Effect of exchange rate changes on cash and cash equivalents	204	206
Increase (decrease) in cash and cash equivalents	(27,286)	524
Cash and cash equivalents at beginning of period	80,900	44,706
Cash and cash equivalents at end of period	$ 53,614	$ 45,230