CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 30, 2013	Mar. 31, 2012
OPERATING ACTIVITIES
Net income	$ 26,780	$ 26,847
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of operating property and intangible assets	7,183	6,740
Non-cash interest charges	55	54
Provisions for losses on trade and other accounts receivable	829	923
Gains on sales/disposals of operating property	(642)	(213)
Deferred income taxes, net	1,263	5,131
Stock-based compensation	1,618	1,525
Changes in operating assets and liabilities:
Decrease (increase) in trade and other accounts receivable	20,288	(17,509)
Decrease in other assets	1,287	3,458
Increase (decrease) in accounts payable	(9,967)	2,544
Increase (decrease) in other liabilities	3,261	(3,046)
Increase (decrease) in insurance claims	879	(6,542)
NET CASH PROVIDED BY OPERATING ACTIVITIES	52,834	19,912
INVESTING ACTIVITIES
Sales and maturities of investments	12,702	8,912
Purchases of investments	(23,152)	(26,214)
Purchases of operating property	(1,722)	(1,026)
Proceeds from sales of operating property	1,943	1,073
NET CASH USED BY INVESTING ACTIVITIES	(10,229)	(17,255)
FINANCING ACTIVITIES
Decrease in cash overdraft	(6,262)	(3,154)
Dividends paid		(2,574)
Proceeds from exercises of stock options	1,611	3,747
Taxes paid in lieu of shares issued related to stock-based compensation plans	(1,633)	(3,024)
Excess tax effect on stock option exercises	255	864
Principal payments on long-term debt and capital lease obligations	(19,853)	(26,006)
NET CASH USED BY FINANCING ACTIVITIES	(25,882)	(30,147)
Effect of exchange rate changes on cash and cash equivalents	(225)	204
Increase (decrease) in cash and cash equivalents	16,498	(27,286)
Cash and cash equivalents at beginning of period	74,284	80,900
Cash and cash equivalents at end of period	$ 90,782	$ 53,614