Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 29, 2014	Dec. 28, 2013
Current Assets
Cash and cash equivalents	$ 114,166	$ 180,302
Short-term investments	35,560	34,939
Trade accounts receivable, less allowance of $3,594 and $3,773	411,545	378,732
Other receivables, including advances to independent contractors, less allowance of $4,212 and $4,253	81,986	73,903
Deferred income taxes and other current assets	14,778	14,592
Total current assets	658,035	682,468
Operating property, less accumulated depreciation and amortization of $160,307 and $157,985	171,717	177,329
Goodwill	31,134	31,134
Other assets	83,236	79,765
Total assets	944,122	970,696
Current Liabilities
Cash overdraft	21,179	27,780
Accounts payable	171,085	157,796
Current maturities of long-term debt	27,685	27,567
Insurance claims	93,790	92,280
Other current liabilities	62,308	70,237
Total current liabilities	376,047	375,660
Long-term debt, excluding current maturities	61,599	73,938
Insurance claims	23,912	24,171
Deferred income taxes and other noncurrent liabilities	39,387	42,446
Shareholders' Equity
Common stock, $0.01 par value, authorized 160,000,000 shares, issued 67,121,124 and 67,017,858 shares	671	670
Additional paid-in capital	180,979	179,807
Retained earnings	1,197,962	1,173,044
Cost of 22,168,803 and 21,528,693 shares of common stock in treasury	(936,101)	(899,028)
Accumulated other comprehensive loss	(334)	(12)
Total shareholders' equity	443,177	454,481
Total liabilities and shareholders' equity	$ 944,122	$ 970,696