CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
CURRENT ASSETS
Cash and cash equivalents	$ 155,531	$ 76,620
Short-term investments	145,758	48,339
Accounts receivable, less allowances (2022 - $15,441; 2021 - $13,226)	627,092	582,344
Other accounts receivable, less allowances (2022 - $709; 2021 - $690)	11,472	13,094
Prepaid expenses	32,280	40,104
Prepaid and refundable income taxes	16,010	9,654
Other	9,885	5,898
TOTAL CURRENT ASSETS	998,028	776,053
PROPERTY, PLANT AND EQUIPMENT
Land and structures	361,705	350,694
Revenue equipment	1,014,369	980,283
Service, office, and other equipment	291,595	251,085
Software	178,145	175,989
Leasehold improvements	20,865	16,931
TOTAL PROPERTY, PLANT AND EQUIPMENT, Gross	1,866,679	1,774,982
Less allowances for depreciation and amortization	1,120,962	1,079,061
PROPERTY, PLANT AND EQUIPMENT, net	745,717	695,921
GOODWILL	307,252	300,337
INTANGIBLE ASSETS, net	116,922	126,580
OPERATING RIGHT-OF-USE ASSETS	164,654	106,686
DEFERRED INCOME TAXES	5,563	5,470
OTHER LONG-TERM ASSETS	101,978	101,629
TOTAL ASSETS	2,440,114	2,112,676
CURRENT LIABILITIES
Accounts payable	329,887	311,401
Income taxes payable	7,668	12,087
Accrued expenses	331,610	305,851
Current portion of long-term debt	63,521	50,615
Current portion of operating lease liabilities	24,686	22,740
TOTAL CURRENT LIABILITIES	757,372	702,694
LONG-TERM DEBT, less current portion	189,798	174,917
OPERATING LEASE LIABILITIES, less current portion	146,134	88,835
POSTRETIREMENT LIABILITIES, less current portion	16,681	16,733
OTHER LONG-TERM LIABILITIES	134,701	135,537
DEFERRED INCOME TAXES	69,136	64,893
STOCKHOLDERS' EQUITY
Common stock, $0.01 par value, authorized 70,000,000 shares; issued 2022: 29,747,867 shares, 2021: 29,359,597 shares	297	294
Additional paid-in capital	337,113	318,033
Retained earnings	1,054,294	801,314
Treasury stock, at cost, 2022: 5,340,836 shares; 2021: 4,492,514 shares	(269,390)	(194,273)
Accumulated other comprehensive income	3,978	3,699
TOTAL STOCKHOLDERS' EQUITY	1,126,292	929,067
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 2,440,114	$ 2,112,676