Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
OPERATING ACTIVITIES OF CONTINUING OPERATIONS
Net income	$ 147,689	$ 138,809	$ 146,009
Adjustments to reconcile net income to net cash provided by operating activities of continuing operations:
Discontinued operations			(37,087)
Depreciation and amortization of operating property	29,102	27,575	27,667
Non-cash interest charges	218	218	219
Provisions for losses on trade and other accounts receivable	5,890	5,315	3,755
Gains on sales/disposals of operating property	(216)	(2,143)	(3,352)
Deferred income taxes, net	6,792	5,434	4,700
Stock-based compensation	6,925	6,797	4,911
Changes in operating assets and liabilities, net of discontinued operations:
Decrease (increase) in trade and other accounts receivable	20,713	(60,454)	(28,584)
Increase in other assets	(1,177)	(9,046)	(1,214)
Increase in accounts payable	3,632	62,281	8,881
Increase (decrease) in other liabilities	1,222	(2,468)	(3,308)
(Decrease) increase in insurance claims	(4,768)	(70,449)	30,048
NET CASH PROVIDED BY OPERATING ACTIVITIES OF CONTINUING OPERATIONS	216,022	101,869	152,645
INVESTING ACTIVITIES OF CONTINUING OPERATIONS
Sales and maturities of investments	38,684	34,701	38,777
Purchases of investments	(44,238)	(36,473)	(50,613)
Purchases of operating property	(4,804)	(10,539)	(6,373)
Proceeds from sales of operating property	1,685	7,465	9,711
Proceeds from sale of discontinued operations			74,505
NET CASH (USED) PROVIDED BY INVESTING ACTIVITIES OF CONTINUING OPERATIONS	(8,673)	(4,846)	66,007
FINANCING ACTIVITIES OF CONTINUING OPERATIONS
Increase in cash overdraft	980	6,849	2,617
Dividends paid	(57,882)	(27,606)
Proceeds from exercises of stock options	1,459	3,760	2,323
Taxes paid in lieu of shares issued related to stock-based compensation plans	(2,225)	(4,041)	(1,766)
Excess tax benefits from stock-based awards	671	2,500	349
Purchases of common stock	(161,152)	(56,393)	(59,496)
Principal payments on long-term debt and capital lease obligations	(36,520)	(37,416)	(61,774)
NET CASH USED BY FINANCING ACTIVITIES OF CONTINUING OPERATIONS	(254,669)	(112,347)	(117,747)
Cash flows from discontinued operations:
Operating activities of discontinued operations			9,368
Investing activities of discontinued operations			(168)
Financing activities of discontinued operations			(3,369)
Net cash provided by discontinued operations			5,831
Effect of exchange rate changes on cash and cash equivalents	(2,104)	(1,034)	(718)
(Decrease) increase in cash and cash equivalents	(49,424)	(16,358)	106,018
Cash and cash equivalents at beginning of period	163,944	180,302	74,284
Cash and cash equivalents at end of period	$ 114,520	$ 163,944	$ 180,302