CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 191,284	$ 224,915
Accounts receivable, net of allowance for credit losses of $10,838 and $10,842 at June 30, 2021 and December 31, 2020, respectively	263,186	160,214
Federal and state income taxes receivable	64	4,428
Inventory	34,924	33,085
Other	54,074	55,314
Total current assets	543,532	477,956
Property and equipment, net	2,424,725	2,761,041
Right of use asset	15,376	16,850
Intangible assets	21,052	30,087
Deposits on equipment purchases	1,782	1,716
Other	10,996	11,419
Total assets	3,017,463	3,299,069
Current liabilities:
Accounts payable	165,779	91,622
Accrued liabilities	167,128	175,004
Lease liability	5,942	7,096
Total current liabilities	338,849	273,722
Long-term lease liability	15,798	19,118
Long-term debt, net of debt discount and issuance costs of $6,859 and $7,271 at June 30, 2021 and December 31, 2020, respectively	902,104	901,484
Deferred tax liabilities, net	22,922	77,676
Other	12,145	11,010
Total liabilities	1,291,818	1,283,010
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 272,835,137 and 271,028,688 issued and 189,004,150 and 187,626,366 outstanding at June 30, 2021 and December 31, 2020, respectively	2,729	2,710
Additional paid-in capital	2,919,090	2,902,236
Retained earnings	167,860	472,014
Accumulated other comprehensive income	5,853	5,412
Treasury stock, at cost, 83,830,987 and 83,402,322 shares at June 30, 2021 and December 31, 2020, respectively	(1,369,887)	(1,366,313)
Total stockholders' equity	1,725,645	2,016,059
Total liabilities and stockholders' equity	$ 3,017,463	$ 3,299,069