CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 126,354	$ 53,910
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation, depletion and amortization	94,148	100,135
Deferred income tax expense	12,371	44,044
Gain on sale of assets	(71)	(71)
Loss (gain) on derivative instruments	13,238	(16,062)
Net cash received in settlement of derivative instruments	3,397	0
Loss on equity method investments	0	59
Amortization of debt issuance costs	715	750
Stock-based compensation and other	11,076	15,765
Changes in assets and liabilities:
Accounts receivable, net	16,881	73,327
Income taxes	23,507	(26,756)
Inventories	(600)	(4,317)
Other current assets	818	916
Accounts payable and accrued liabilities	3,425	(23,711)
Interest payable	(12,915)	(12,981)
Other assets and liabilities	(1,817)	(111)
Net cash provided by operating activities	290,527	204,897
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(123,617)	(148,702)
Proceeds from sale of assets	92	48
Investment in equity method investments	0	(35)
Proceeds from sale of equity method investments	0	(9,424)
Net cash used in investing activities	(123,525)	(158,113)
CASH FLOWS FROM FINANCING ACTIVITIES
Repayments of debt	(88,000)	0
Dividends paid	(39,887)	(39,817)
Tax withholdings on vesting of stock awards	(5,569)	(6,313)
Net cash used in financing activities	(133,456)	(46,130)
Net increase in cash, cash equivalents and restricted cash	33,546	654
Cash, cash equivalents and restricted cash, beginning of period	151,691	213,783
Cash, cash equivalents and restricted cash, end of period	$ 185,237	$ 214,437