Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current Assets:
Cash and cash equivalents	$ 53,260	$ 25,308
Accounts receivable, net	242,895	216,899
Income tax receivable		96
Prepaid expenses and other	52,160	29,393
Total current assets	348,315	271,696
Property and Equipment, at cost	1,918,279	1,901,244
Less: accumulated depreciation	796,511	765,217
Net property and equipment	1,121,768	1,136,027
Operating Lease Right-of-Use Assets	111,737	113,715
Goodwill and Identifiable Intangibles, net	20,030	20,321
Other Noncurrent Assets	8,735	7,015
Total assets	1,610,585	1,548,774
Current Liabilities:
Accounts payable	121,613	89,381
Wages, vacation and employees’ benefits	49,007	55,392
Claims and insurance accruals	46,962	49,613
Other current liabilities	48,285	40,571
Current portion of long-term debt	21,055	20,588
Current portion of operating lease liability	20,336	20,209
Total current liabilities	307,258	275,754
Other Liabilities:
Long-term debt, less current portion	44,962	50,388
Operating lease liability, less current portion	93,366	95,321
Deferred income taxes	121,144	119,818
Claims, insurance and other	46,237	46,205
Total other liabilities	305,709	311,732
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, 26,333,692 and 26,236,570 shares issued and outstanding at March 31, 2021 and December 31, 2020, respectively	26	26
Additional paid-in-capital	267,430	267,666
Deferred compensation trust, 94,888 and 91,888 shares of common stock at cost at March 31, 2021 and December 31, 2020, respectively	(3,669)	(2,944)
Retained earnings	733,831	696,540
Total stockholders’ equity	997,618	961,288
Total liabilities and stockholders’ equity	$ 1,610,585	$ 1,548,774