CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	[1]	Sep. 30, 2018	Sep. 30, 2017	[1]
Revenues
Revenue from sales to customers	$ 659,806	$ 511,192		$ 1,921,910	$ 1,498,093
Gain (loss) on crude contracts	(2,223)	(13,573)		(69,349)	50,365
Gain on sale of assets and other income	17,214	700		26,035	134,780
Total revenues	674,797	498,319		1,878,596	1,683,238
Costs and expenses
Lease operating expenses	133,141	112,751		406,226	346,072
Severance and ad valorem taxes	15,067	10,816		40,100	32,771
Exploration expenses, including undeveloped lease amortization	21,838	28,492		69,911	77,356
Selling and general expenses	64,107	51,374		173,324	155,438
Depreciation, depletion and amortization	241,833	243,636		710,563	714,782
Accretion of asset retirement obligations	11,099	10,654		32,041	31,638
Redetermination expense	11,332			11,332
Other expense (benefit)	(34,387)	2,454		(44,776)	10,988
Total costs and expenses	464,030	460,177		1,398,721	1,369,045
Operating income from continuing operations	210,767	38,142		479,875	314,193
Other income (loss)
Interest and other income (loss)	(19,478)	(53,019)		(19,445)	(106,345)
Interest expense, net	(44,492)	(48,681)		(134,264)	(138,423)
Total other loss	(63,970)	(101,700)		(153,709)	(244,768)
Income (loss) from continuing operations before income taxes	146,797	(63,558)		326,166	69,425
Income tax expense (benefit)	51,038	2,760		15,801	95,602
Income (loss) from continuing operations	95,759	(66,318)		310,365	(26,177)
Income (loss) from discontinued operations, net of income taxes	(1,815)	425		(2,650)	1,177
NET INCOME (LOSS)	$ 93,944	$ (65,893)		$ 307,715	$ (25,000)
INCOME (LOSS) PER COMMON SHARE - BASIC
Continuing operations	$ 0.55	$ (0.38)		$ 1.79	$ (0.15)
Discontinued operations	(0.01)			(0.01)	0.01
Net Income (Loss)	0.54	(0.38)		1.78	(0.14)
INCOME (LOSS) PER COMMON SHARE - DILUTED
Continuing operations	0.55	(0.38)		1.78	(0.15)
Discontinued operations	(0.01)			(0.01)	0.01
Net Income (Loss)	0.54	(0.38)		1.77	(0.14)
Cash dividends per Common share	$ 0.25	$ 0.25		$ 0.75	$ 0.75
Average Common shares outstanding
Basic	173,047,246	172,572,873		172,949,450	172,509,418
Diluted	174,175,267	172,572,873		174,201,760	172,509,418

[1] Reclassified to conform to current presentation (see Note B).