Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current Assets:
Cash and cash equivalents	$ 141,325	$ 106,588
Accounts receivable, net	322,343	276,755
Prepaid expenses and other	46,998	32,912
Total current assets	510,666	416,255
Property and Equipment, at cost	2,162,492	2,144,528
Less: accumulated depreciation	890,927	864,074
Net property and equipment	1,271,565	1,280,454
Operating Lease Right-of-Use Assets	103,892	107,781
Goodwill and Identifiable Intangibles, net	18,866	19,157
Other Noncurrent Assets	27,360	21,603
Total assets	1,932,349	1,845,250
Current Liabilities:
Accounts payable	130,163	114,010
Wages, vacation and employees’ benefits	62,125	73,109
Claims and insurance accruals	44,853	54,717
Other current liabilities	61,618	38,551
Current portion of long-term debt	18,373	19,396
Current portion of operating lease liability	21,989	21,565
Total current liabilities	339,121	321,348
Other Liabilities:
Long-term debt, less current portion	26,506	31,008
Operating lease liability, less current portion	84,062	88,409
Deferred income taxes	122,106	124,137
Claims, insurance and other	69,064	60,015
Total other liabilities	301,738	303,569
Stockholders’ Equity:
Preferred stock, $0.001 par value, 50,000 shares authorized, none issued and outstanding
Common stock, $0.001 par value, 50,000,000 shares authorized, 26,408,402 and 26,336,589 shares issued and outstanding at March 31, 2022 and December 31, 2021, respectively	26	26
Additional paid-in-capital	267,745	274,633
Deferred compensation trust, 80,174 and 94,627 shares of common stock at cost at March 31, 2022 and December 31, 2021, respectively	(5,480)	(4,101)
Retained earnings	1,029,199	949,775
Total stockholders’ equity	1,291,490	1,220,333
Total liabilities and stockholders’ equity	$ 1,932,349	$ 1,845,250