CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 534,130	$ 281,998
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation, depletion and amortization	299,294	288,210
Deferred income tax expense	188,997	131,799
Loss on sale of assets	1,464	14,850
Exploratory dry hole cost	16	56,425
(Gain) loss on derivative instruments	(82,966)	1,628
Net cash received (paid) in settlement of derivative instruments	114,931	(20,354)
(Earnings) loss on equity method investments	(11,194)	1,009
Distribution of earnings from equity method investments	12,610	0
Amortization of debt issuance costs	3,219	3,521
Stock-based compensation and other	22,720	16,472
Changes in assets and liabilities:
Accounts receivable, net	203,164	(7,345)
Income taxes	(16,746)	(14,447)
Inventories	(7,119)	(5,326)
Other current assets	(1,338)	104
Accounts payable and accrued liabilities	(43,413)	32,192
Interest payable	(12,825)	(18,474)
Other assets and liabilities	(22,133)	26,590
Net cash provided by operating activities	1,182,811	788,852
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(620,696)	(647,503)
Proceeds from sale of assets	2,401	675,525
Investment in equity method investments	(8,977)	(72,866)
Distribution of investment from equity method investments	1,656	0
Net cash used in investing activities	(625,616)	(44,844)
CASH FLOWS FROM FINANCING ACTIVITIES
Borrowings from debt	95,000	0
Repayments of debt	(102,000)	(237,000)
Treasury stock repurchases	(347,446)	(581,725)
Dividends paid	(104,722)	(81,185)
Tax withholdings on vesting of stock awards	(10,587)	(8,068)
Capitalized debt issuance costs	(7,411)	0
Net cash used in financing activities	(477,166)	(907,978)
Net increase (decrease) in cash and cash equivalents	80,029	(163,970)
Cash and cash equivalents, beginning of period	2,287	480,047
Cash and cash equivalents, end of period	$ 82,316	$ 316,077