CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
CURRENT ASSETS
Cash and cash equivalents	$ 88,553	$ 90,702
Short-term investments	29,879	29,054
Restricted cash, cash equivalents, and short-term investments	1,901	9,658
Accounts receivable, less allowances (2013 - $5,439; 2012 - $5,249)	206,168	180,631
Other accounts receivable, less allowances (2013 - $1,427; 2012 - $1,334)	6,615	6,539
Prepaid expenses	16,346	17,355
Deferred income taxes	42,293	39,245
Prepaid and refundable income taxes	6,232	5,681
Other	7,306	7,185
TOTAL CURRENT ASSETS	405,293	386,050
PROPERTY, PLANT AND EQUIPMENT
Land and structures	245,148	243,699
Revenue equipment	590,445	589,729
Service, office, and other equipment	120,848	119,456
Software	107,195	103,164
Leasehold improvements	23,442	23,272
TOTAL PROPERTY, PLANT AND EQUIPMENT, GROSS	1,087,078	1,079,320
Less allowances for depreciation and amortization	673,074	635,292
TOTAL PROPERTY, PLANT AND EQUIPMENT, NET	414,004	444,028
GOODWILL	76,448	73,189
INTANGIBLE ASSETS, net	77,474	79,561
OTHER ASSETS	51,381	51,634
TOTAL ASSETS	1,024,600	1,034,462
CURRENT LIABILITIES
Bank overdraft and drafts payable	15,672	13,645
Accounts payable	94,770	84,292
Income taxes payable	162	59
Accrued expenses	170,414	158,668
Current portion of long-term debt	37,030	43,044
TOTAL CURRENT LIABILITIES	318,048	299,708
LONG-TERM DEBT, less current portion	96,946	112,941
PENSION AND POSTRETIREMENT LIABILITIES	51,941	104,673
OTHER LIABILITIES	12,558	12,832
DEFERRED INCOME TAXES	63,954	45,309
STOCKHOLDERS' EQUITY
Common stock, $0.01 par value, authorized 70,000,000 shares; issued 2013: 27,390,446 shares; 2012: 27,296,285 shares	274	273
Additional paid-in capital	290,355	289,711
Retained earnings	274,027	284,157
Treasury stock, at cost, 1,677,932 shares	(57,770)	(57,770)
Accumulated other comprehensive loss	(25,733)	(57,372)
TOTAL STOCKHOLDERS' EQUITY	481,153	458,999
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 1,024,600	$ 1,034,462