CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	[1]	Jun. 30, 2018	Jun. 30, 2017	[1]
Revenues
Revenue from sales to customers	$ 655,150	$ 477,560		$ 1,262,104	$ 986,595
(Loss) gain on crude contracts	(37,624)	26,861		(67,126)	63,938
Gain on sale of assets and other income	668	3,858		8,821	134,386
Total revenues	618,194	508,279		1,203,799	1,184,919
Costs and expenses
Lease operating expenses	136,589	111,179		273,085	233,321
Severance and ad valorem taxes	12,876	10,742		25,033	21,955
Exploration expenses, including undeveloped lease amortization	19,145	20,201		48,073	48,864
Selling and general expenses	57,800	52,809		109,217	102,774
Depreciation, depletion and amortization	237,997	234,992		468,730	471,146
Accretion of asset retirement obligations	11,028	10,428		20,942	20,984
Other expense (benefit)	659	6,377		(10,389)	8,534
Total costs and expenses	476,094	446,728		934,691	907,578
Operating income from continuing operations	142,100	61,551		269,108	277,341
Other income (loss)
Interest and other income (loss)	(15,051)	(38,305)		33	(54,616)
Interest expense, net	(44,723)	(45,145)		(89,772)	(89,742)
Total other loss	(59,774)	(83,450)		(89,739)	(144,358)
Income (loss) from continuing operations before income taxes	82,326	(21,899)		179,369	132,983
Income tax expense (benefit)	36,410	(4,545)		(35,237)	92,842
Income (loss) from continuing operations	45,916	(17,354)		214,606	40,141
Income (loss) from discontinued operations, net of income taxes	(398)	(217)		(835)	752
NET INCOME (LOSS)	$ 45,518	$ (17,571)		$ 213,771	$ 40,893
INCOME (LOSS) PER COMMON SHARE - BASIC
Continuing operations	$ 0.26	$ (0.10)		$ 1.25	$ 0.23
Discontinued operations				(0.01)	0.01
Net Income (Loss)	0.26	(0.10)		1.24	0.24
INCOME (LOSS) PER COMMON SHARE - DILUTED
Continuing operations	0.26	(0.10)		1.23	0.23
Discontinued operations				(0.01)	0.01
Net Income (Loss)	0.26	(0.10)		1.22	0.24
Cash dividends per Common share	$ 0.25	$ 0.25		$ 0.50	$ 0.50
Average Common shares outstanding
Basic	173,042,626	172,557,978		172,907,537	172,482,223
Diluted	173,982,620	172,557,978		174,927,062	173,016,664

[1] Reclassified to conform to current presentation (see Notes A and B).