CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
CURRENT ASSETS
Cash and cash equivalents	$ 75,071	$ 90,702
Short-term investments	29,891	29,054
Restricted cash, cash equivalents, and short-term investments	5,904	9,658
Accounts receivable, less allowances (2013 - $5,360; 2012 - $5,249)	190,036	180,631
Other accounts receivable, less allowances (2013 - $1,376; 2012 - $1,334)	6,011	6,539
Prepaid expenses	19,397	17,355
Deferred income taxes	37,302	39,245
Prepaid and refundable income taxes	7,851	5,681
Other	7,288	7,185
TOTAL CURRENT ASSETS	378,751	386,050
PROPERTY, PLANT AND EQUIPMENT
Land and structures	243,990	243,699
Revenue equipment	588,809	589,729
Service, office, and other equipment	119,642	119,456
Software	105,164	103,164
Leasehold improvements	23,357	23,272
TOTAL PROPERTY, PLANT AND EQUIPMENT, GROSS	1,080,962	1,079,320
Less allowances for depreciation and amortization	653,862	635,292
TOTAL PROPERTY, PLANT AND EQUIPMENT, NET	427,100	444,028
GOODWILL	75,032	73,189
INTANGIBLE ASSETS, net	78,518	79,561
OTHER ASSETS	51,994	51,634
TOTAL ASSETS	1,011,395	1,034,462
CURRENT LIABILITIES
Bank overdraft and drafts payable	11,737	13,645
Accounts payable	84,966	84,292
Income taxes payable	75	59
Accrued expenses	167,848	158,668
Current portion of long-term debt	39,861	43,044
TOTAL CURRENT LIABILITIES	304,487	299,708
LONG-TERM DEBT, less current portion	105,169	112,941
PENSION AND POSTRETIREMENT LIABILITIES	105,922	104,673
OTHER LIABILITIES	12,366	12,832
DEFERRED INCOME TAXES	35,858	45,309
STOCKHOLDERS' EQUITY
Common stock, $0.01 par value, authorized 70,000,000 shares; issued 2013: 27,307,505 shares; 2012: 27,296,285 shares	273	273
Additional paid-in capital	290,776	289,711
Retained earnings	269,955	284,157
Treasury stock, at cost, 1,677,932 shares	(57,770)	(57,770)
Accumulated other comprehensive loss	(55,641)	(57,372)
TOTAL STOCKHOLDERS' EQUITY	447,593	458,999
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 1,011,395	$ 1,034,462