CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
CURRENT ASSETS
Cash and cash equivalents	$ 127,444	$ 262,226
Short-term investments	29,759	67,842
Accounts receivable, less allowances (2024 - $8,257; 2023 - $10,346)	394,838	430,122
Other accounts receivable, less allowances (2024 - $648; 2023 - $731)	36,055	52,124
Prepaid expenses	47,860	37,034
Prepaid and refundable income taxes	28,641	24,319
Other	11,045	11,116
TOTAL CURRENT ASSETS	675,642	884,783
PROPERTY, PLANT AND EQUIPMENT
Land and structures	520,119	460,068
Revenue equipment	1,166,161	1,126,055
Service, office, and other equipment	351,907	319,466
Software	182,396	173,354
Leasehold improvements	32,263	24,429
TOTAL PROPERTY, PLANT AND EQUIPMENT, Gross	2,252,846	2,103,372
Less allowances for depreciation and amortization	1,186,800	1,188,548
PROPERTY, PLANT AND EQUIPMENT, net	1,066,046	914,824
GOODWILL	304,753	304,753
INTANGIBLE ASSETS, net	88,615	101,150
OPERATING RIGHT-OF-USE ASSETS	192,753	169,999
DEFERRED INCOME TAXES	9,536	8,140
OTHER LONG-TERM ASSETS	92,386	101,445
TOTAL ASSETS	2,429,731	2,485,094
CURRENT LIABILITIES
Accounts payable	172,763	214,004
Income taxes payable		10,410
Accrued expenses	394,880	378,029
Current portion of long-term debt	63,978	66,948
Current portion of operating lease liabilities	34,364	32,172
TOTAL CURRENT LIABILITIES	665,985	701,563
LONG-TERM DEBT, less current portion	125,156	161,990
OPERATING LEASE LIABILITIES, less current portion	189,978	176,621
POSTRETIREMENT LIABILITIES, less current portion	13,361	13,319
CONTINGENT CONSIDERATION	2,650	92,900
DEFERRED INCOME TAXES	78,649	55,785
OTHER LONG-TERM LIABILITIES	39,590	40,553
STOCKHOLDERS' EQUITY
Common stock, $0.01 par value, authorized 70,000,000 shares; issued 2024: 30,401,768 shares; 2023: 30,024,125 shares	304	300
Additional paid-in capital	329,575	340,961
Retained earnings	1,435,250	1,272,584
Treasury stock, at cost, 2024: 7,114,844 shares; 2023: 6,460,137 shares	(451,039)	(375,806)
Accumulated other comprehensive income	272	4,324
TOTAL STOCKHOLDERS' EQUITY	1,314,362	1,242,363
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 2,429,731	$ 2,485,094