Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 28, 2013	Dec. 29, 2012	Dec. 31, 2011
OPERATING ACTIVITIES OF CONTINUING OPERATIONS
Net income	$ 146,009	$ 129,781	$ 113,007
Adjustments to reconcile net income to net cash provided by operating activities of continuing operations:
Discontinued operations	(37,087)	(3,215)	(1,464)
Depreciation and amortization of operating property	27,667	25,213	23,905
Non-cash interest charges	219	218	218
Provisions for losses on trade and other accounts receivable	3,755	4,886	7,626
Gains on sales/disposals of operating property	(3,352)	(2,815)	(274)
Deferred income taxes, net	4,700	4,261	10,071
Stock-based compensation	4,911	6,149	5,012
Changes in operating assets and liabilities, net of discontinued operations:
Increase in trade and other accounts receivable	(28,584)	(35,140)	(95,349)
Decrease (increase) in other assets	(1,214)	2,547	1,930
Increase in accounts payable	8,881	13,018	21,583
Decrease in other liabilities	(3,308)	(6,857)	(4,537)
Increase (decrease) in insurance claims	30,048	(17,715)	32,435
NET CASH PROVIDED BY OPERATING ACTIVITIES OF CONTINUING OPERATIONS	152,645	120,331	114,163
INVESTING ACTIVITIES OF CONTINUING OPERATIONS
Sales and maturities of investments	38,777	33,028	67,174
Purchases of investments	(50,613)	(56,897)	(58,413)
Purchases of operating property	(6,373)	(5,388)	(3,624)
Proceeds from sales of operating property	9,711	9,730	4,385
Proceeds from sale of discontinued operations	74,505
NET CASH PROVIDED (USED) BY INVESTING ACTIVITIES OF CONTINUING OPERATIONS	66,007	(19,527)	9,522
FINANCING ACTIVITIES OF CONTINUING OPERATIONS
Increase (decrease) in cash overdraft	2,617	(339)	938
Dividends on common stock		(33,981)	(9,983)
Proceeds from exercises of stock options	2,323	4,383	1,025
Taxes paid in lieu of shares issued related to stock-based compensation plans	(1,766)	(3,023)	(102)
Excess (shortfall) tax effect on stock option exercises	349	751	(683)
Borrowings on revolving credit facility		60,000	10,000
Purchases of common stock	(59,496)	(25,826)	(50,450)
Principal payments on long-term debt and capital lease obligations	(61,774)	(121,278)	(33,245)
Purchase of noncontrolling interest			(8,000)
NET CASH USED BY FINANCING ACTIVITIES OF CONTINUING OPERATIONS	(117,747)	(119,313)	(90,500)
Cash flows from discontinued operations:
Operating activities of discontinued operations	9,368	5,253	3,871
Investing activities of discontinued operations	(168)	(1,684)	(713)
Financing activities of discontinued operations	(3,369)	8,081	22
Net cash provided by discontinued operations	5,831	11,650	3,180
Effect of exchange rate changes on cash and cash equivalents	(718)	243	(171)
Increase (decrease) in cash and cash equivalents	106,018	(6,616)	36,194
Cash and cash equivalents at beginning of period	74,284	80,900	44,706
Cash and cash equivalents at end of period	$ 180,302	$ 74,284	$ 80,900