Consolidated Statements Of Cash Flows (USD $) In Thousands	6 Months Ended
	Jun. 25, 2011	Jun. 26, 2010
OPERATING ACTIVITIES
Net income	$ 50,155	$ 41,167
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of operating property and intangible assets	12,787	11,988
Non-cash interest charges	109	110
Provisions for losses on trade and other accounts receivable	2,862	2,434
Losses on sales/disposals of operating property	106	176
Deferred income taxes, net	(3,715)	893
Stock-based compensation	2,473	2,368
Changes in operating assets and liabilities:
Increase in trade and other accounts receivable	(82,602)	(66,427)
Decrease (increase) in other assets	101	(2,233)
Increase in accounts payable	38,028	38,518
Increase (decrease) in other liabilities	(869)	4,636
Increase (decrease) in insurance claims	4,032	(7,383)
NET CASH PROVIDED BY OPERATING ACTIVITIES	23,467	26,247
INVESTING ACTIVITIES
Net change in other short-term investments		1,730
Sales and maturities of investments	44,822	17,136
Purchases of investments	(39,441)	(47,716)
Purchases of operating property	(2,829)	(24,684)
Proceeds from sales of operating property	729	341
NET CASH PROVIDED (USED) BY INVESTING ACTIVITIES	3,281	(53,193)
FINANCING ACTIVITIES
Increase in cash overdraft	1,470	1,374
Dividends paid	(4,788)	(4,527)
Proceeds from exercises of stock options	555	1,508
Excess (shortfall) tax effect on stock option exercises	(122)	1,157
Borrowings on revolving credit facility		25,000
Purchases of common stock	(9,266)	(25,060)
Principal payments on capital lease obligations	(11,972)	(13,201)
Purchase of noncontrolling interest	(8,000)
NET CASH USED BY FINANCING ACTIVITIES	(32,123)	(13,749)
Effect of exchange rate changes on cash and cash equivalents	213	57
Decrease in cash and cash equivalents	(5,162)	(40,638)
Cash and cash equivalents at beginning of period	44,706	85,719
Cash and cash equivalents at end of period	$ 39,544	$ 45,081