CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 224,915	$ 174,185
Accounts receivable, net of allowance for credit losses of $10,842 and $6,516 at December 31, 2020 and 2019, respectively	160,214	339,699
Federal and state income taxes receivable	4,428	6,397
Inventory	33,085	36,357
Other	55,314	75,177
Total current assets	477,956	631,815
Property and equipment, net	2,761,041	3,306,677
Right of use asset	16,850	31,275
Goodwill and intangible assets	30,087	444,004
Deposits on equipment purchases	1,716	8,066
Other	11,419	17,778
Total assets	3,299,069	4,439,615
Current liabilities:
Accounts payable	91,622	170,475
Federal and state income taxes payable		342
Accrued liabilities	175,004	219,850
Lease liability	7,096	9,935
Total current liabilities	273,722	400,602
Long-term lease liability	19,118	26,644
Long-term debt, net of debt discount and issuance costs of $7,271 and $8,460 at December 31, 2020 and 2019, respectively	901,484	966,540
Deferred tax liabilities, net	77,676	202,959
Other	11,010	9,250
Total liabilities	1,283,010	1,605,995
Commitments and contingencies (see Note 10)
Stockholders’ equity:
Preferred stock, par value $0.01; authorized 1,000,000 shares, no shares issued
Common stock, par value $0.01; authorized 400,000,000 shares with 271,028,688 and 269,372,257 issued and 187,626,366 and 192,035,870 outstanding at December 31, 2020 and 2019, respectively	2,710	2,694
Additional paid-in capital	2,902,236	2,875,680
Retained earnings	472,014	1,294,902
Accumulated other comprehensive income	5,412	5,478
Treasury stock, at cost, 83,402,322 shares and 77,336,387 shares at December 31, 2020 and 2019, respectively	(1,366,313)	(1,345,134)
Total stockholders’ equity	2,016,059	2,833,620
Total liabilities and stockholders’ equity	$ 3,299,069	$ 4,439,615