Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current Assets:
Cash and cash equivalents	$ 296,215	$ 187,390
Accounts receivable, less allowances of $4,427 in 2023 and $5,804 in 2022	311,742	290,306
Prepaid expenses	32,648	22,525
Income tax receivable	1,005	23,438
Other current assets	7,084	7,227
Total current assets	648,694	530,886
Property and Equipment, at cost	2,881,800	2,478,824
Less-accumulated depreciation and amortization	1,118,492	996,204
Net property and equipment	1,763,308	1,482,620
Operating Lease Right-of-Use Assets	118,734	120,455
Goodwill and Identifiable Intangibles, net	17,296	18,149
Other Noncurrent Assets	35,533	22,600
Total assets	2,583,565	2,174,710
Current Liabilities:
Accounts payable	141,877	99,792
Wages, vacation and employees’ benefits	75,514	66,684
Claims and insurance accruals	41,641	45,481
Other current liabilities	27,094	22,684
Current portion of long-term debt	10,173	14,519
Current portion of operating lease liability	25,757	24,925
Total current liabilities	322,056	274,085
Other Liabilities:
Long-term debt, less current portion	6,315	16,489
Operating lease liability, less current portion	96,462	98,581
Deferred income taxes	155,841	145,771
Claims, insurance and other	61,397	60,443
Total other liabilities	320,015	321,284
Commitments and Contingencies (Note 3)	0	0
Stockholders’ Equity:
Preferred stock, $0.001 par value, 50,000 shares authorized, none issued and outstanding	0	0
Common stock, $0.001 par value, 100,000,000 shares authorized, 26,549,372 and 26,464,197 shares issued and outstanding at December 31, 2023 and 2022, respectively	27	26
Additional paid-in-capital	285,092	277,366
Deferred compensation trust, 69,672 and 69,982 shares of common stock at cost at December 31, 2023 and 2022, respectively	(5,679)	(5,248)
Retained earnings	1,662,054	1,307,197
Total stockholders’ equity	1,941,494	1,579,341
Total liabilities and stockholders’ equity	$ 2,583,565	$ 2,174,710