CONSOLIDATED BALANCE SHEETS (in thousands, except share data) - USD ($) $ in Thousands	Jan. 01, 2018	Dec. 31, 2018		Dec. 31, 2017
Current assets:
Cash and cash equivalents		$ 77,965		$ 313,943
Accounts receivable		167,536		160,154
Derivative assets		175,130		64,266
Prepaid expenses and other		8,632		10,752
Total current assets		429,263		549,115
Property and equipment (successful efforts method):
Proved oil and gas properties		7,278,362		6,139,379
Accumulated depletion, depreciation, and amortization		(3,417,953)		(3,171,575)
Unproved oil and gas properties		1,581,401		2,047,203
Wells in progress		295,529		321,347
Properties held for sale, net		5,280		111,700
Other property and equipment, net of accumulated depreciation of $57,102 and $49,985, respectively		88,546		106,738
Total property and equipment, net		5,831,165		5,554,792
Noncurrent assets:
Derivative assets		58,499		40,362
Other noncurrent assets		33,935		32,507
Total noncurrent assets		92,434		72,869
Total assets		6,352,862		6,176,776
Current liabilities:
Accounts payable and accrued expenses		403,199		386,630
Derivative liabilities		62,853		172,582
Total current liabilities		466,052		559,212
Noncurrent liabilities:
Revolving credit facility		0		0
Senior Notes, net of unamortized deferred financing costs		2,448,439		2,769,663
Senior Convertible Notes, net of unamortized discount and deferred financing costs		147,894		139,107
Asset retirement obligations		91,859		103,026
Asset retirement obligations associated with oil and gas properties held for sale		0		11,369
Deferred income taxes		223,278		79,989
Derivative liabilities		12,496		71,402
Other noncurrent liabilities		42,522		48,400
Total noncurrent liabilities		2,966,488		3,222,956
Commitments and contingencies (note 6)
Stockholders' Equity:
Common stock, $0.01 par value - authorized: 200,000,000 shares; issued and outstanding: 112,241,966 and 111,687,016 shares, respectively		1,122		1,117
Additional paid-in capital		1,765,738		1,741,623
Retained earnings		1,165,842	[1]	665,657
Accumulated other comprehensive loss		(12,380)	[1]	(13,789)
Total stockholders' equity		2,920,322		2,394,608
Total liabilities and stockholders' equity		$ 6,352,862		$ 6,176,776
Accounting Standards Update 2018-02 [Member]
Cumulative Effect on Retained Earnings, Net of Tax	$ 3,000

[1] (1) The Company reclassified $3.0 million of tax effects stranded in accumulated other comprehensive loss to retained earnings as of January 1, 2018. Please refer to Note 1 – Summary of Significant Accounting Policies for further detail.