Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 28, 2014	Jun. 29, 2013
OPERATING ACTIVITIES OF CONTINUING OPERATIONS
Net income	$ 63,563	$ 57,206
Adjustments to reconcile net income to net cash provided by operating activities of continuing operations:
Discontinued operations		(1,963)
Depreciation and amortization of operating property	13,333	13,563
Non-cash interest charges	109	109
Provisions for losses on trade and other accounts receivable	2,650	1,565
Gains on sales/disposals of operating property	(736)	(2,359)
Deferred income taxes, net	1,304	6,071
Stock-based compensation	2,799	2,992
Changes in operating assets and liabilities, net of discontinued operations:
Decrease (increase) in trade and other accounts receivable	(64,709)	11,401
Increase in other assets	(15,592)	(6,273)
Increase in accounts payable	37,539	78
Decrease in other liabilities	(11,939)	(3,780)
Increase (decrease) in insurance claims	(14,721)	1,526
NET CASH PROVIDED BY OPERATING ACTIVITIES OF CONTINUING OPERATIONS	13,600	80,136
INVESTING ACTIVITIES OF CONTINUING OPERATIONS
Net change in other short-term investments	(3,225)
Sales and maturities of investments	20,830	24,296
Purchases of investments	(21,807)	(35,157)
Purchases of operating property	(1,354)	(2,744)
Proceeds from sales of operating property	2,410	6,826
NET CASH USED BY INVESTING ACTIVITIES OF CONTINUING OPERATIONS	(3,146)	(6,779)
FINANCING ACTIVITIES OF CONTINUING OPERATIONS
Decrease in cash overdraft	(578)	(2,525)
Dividends paid	(21,341)
Proceeds from exercises of stock options	2,111	1,885
Taxes paid in lieu of shares issued related to stock-based compensation plans	(1,724)	(1,633)
Excess tax effect on stock option exercises	669	252
Purchases of common stock	(56,393)	(46,603)
Principal payments on long-term debt and capital lease obligations	(20,110)	(31,560)
NET CASH USED BY FINANCING ACTIVITIES OF CONTINUING OPERATIONS	(97,366)	(80,184)
Cash flows from discontinued operations:
Operating activities of discontinued operations		4,629
Investing activities of discontinued operations		(5)
Financing activities of discontinued operations		(4,097)
Net cash provided by discontinued operations		527
Effect of exchange rate changes on cash and cash equivalents	(257)	(510)
Decrease in cash and cash equivalents	(87,169)	(6,810)
Cash and cash equivalents at beginning of period	180,302	74,284
Cash and cash equivalents at end of period	$ 93,133	$ 67,474