Carrizo Oil & Gas (CRZO) 10-Q 8 Aug 19 2019 Q2 Quarterly report Financial data

Cover

Cover - shares	6 Months Ended
	Jun. 30, 2019	Aug. 02, 2019
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2019
Document Transition Report	false
Entity File Number	000-29187-87
Entity Registrant Name	CARRIZO OIL & GAS, INC.
Entity Incorporation, State or Country Code	TX
Entity Tax Identification Number	76-0415919
Entity Address, Address Line One	500 Dallas Street,
Entity Address, Address Line Two	Suite 2300,
Entity Address, City or Town	Houston,
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77002
Amendment Flag	false
City Area Code	713)
Local Phone Number	328-1000
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	CRZO
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		92,552,930
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Entity Central Index Key	0001040593
Current Fiscal Year End Date	--12-31

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 2,282,000	$ 2,282,000
Accounts receivable, net	98,444,000	99,723,000
Derivative assets, current	13,621,000	39,904,000
Other current assets	9,472,000	8,460,000
Total current assets	123,819,000	150,369,000
Oil and gas properties, full cost method
Proved properties, net	2,587,341,000	2,333,470,000
Unproved properties, not being amortized	656,976,000	673,833,000
Other property and equipment, net	11,188,000	11,221,000
Total property and equipment, net	3,255,505,000	3,018,524,000
Deferred income tax asset, noncurrent	177,723,000	0
Operating lease right-of-use assets	64,615,000	0
Other long-term assets	13,666,000	16,207,000
Total Assets	3,635,328,000	3,185,100,000
Current liabilities
Accounts payable	102,943,000	98,811,000
Revenues and royalties payable	54,662,000	49,003,000
Accrued capital expenditures	74,005,000	60,004,000
Accrued interest	18,700,000	18,377,000
Derivative liabilities	64,751,000	55,205,000
Operating lease liabilities	34,049,000	0
Other current liabilities	51,430,000	40,609,000
Total current liabilities	400,540,000	322,009,000
Long-term debt	1,731,418,000	1,633,591,000
Asset retirement obligations	22,111,000	18,360,000
Operating lease liabilities	36,526,000	0
Deferred income tax liabilities, noncurrent	8,218,000	8,017,000
Other long-term liabilities	20,101,000	47,797,000
Liabilities	2,218,914,000	2,029,774,000
Preferred stock, $0.01 par value, 10,000,000 shares authorized; 200,000 issued and outstanding as of June 30, 2019 and December 31, 2018	176,056,000	174,422,000
Shareholders’ equity
Common stock, $0.01 par value, 180,000,000 shares authorized; 92,552,930 issued and outstanding as of June 30, 2019 and 91,627,738 issued and outstanding as of December 31, 2018	926,000	916,000
Additional paid-in capital	2,132,131,000	2,131,535,000
Accumulated deficit	(892,699,000)	(1,151,547,000)
Total shareholders’ equity	1,240,358,000	980,904,000
Total Liabilities and Shareholders’ Equity	$ 3,635,328,000	$ 3,185,100,000

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)		$ 0.01
Common stock, shares authorized (in shares)	180,000,000	180,000,000
Common stock, shares issued (in shares)	92,552,930	91,627,738
Common stock, shares outstanding (in shares)	92,552,930	91,627,738
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	10,000,000	10,000,000
Preferred Stock, Shares Issued	200,000	200,000
Preferred Stock, Shares Outstanding	200,000	200,000

Consolidated Statements Of Oper

Consolidated Statements Of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues	$ 264,967	$ 263,973	$ 498,007	$ 489,253
Costs and Expenses
Lease operating	44,514	35,151	86,545	74,424
Production and ad valorem taxes	17,793	16,127	32,687	28,675
Depreciation, depletion and amortization	80,766	72,430	156,088	136,897
General and administrative, net	17,301	18,265	42,033	45,557
(Gain) loss on derivatives, net	(20,449)	67,714	62,835	97,310
Interest expense, net	18,024	15,599	34,475	31,116
Loss on extinguishment of debt	0	0	0	8,676
Other (income) expense, net	(2,766)	2,895	1,592	2,995
Total Costs and Expenses	155,183	228,181	416,255	425,650
Income Before Income Taxes	109,784	35,792	81,752	63,603
Income tax (expense) benefit	(2,299)	(483)	177,096	(802)
Net Income (loss)	107,485	35,309	258,848	62,801
Dividends on preferred stock	(4,452)	(4,474)	(8,812)	(9,337)
Accretion on preferred stock	(833)	(740)	(1,634)	(1,493)
Loss on redemption of preferred stock	0	0	0	(7,133)
Net Income Attributable to Common Shareholders	$ 102,200	$ 30,095	$ 248,402	$ 44,838
Net Income Attributable to Common Shareholders Per Common Share
Income (loss) per share, basic (in dollars per share)	$ 1.10	$ 0.37	$ 2.70	$ 0.55
Income (loss) per share, diluted (in dollars per share)	$ 1.10	$ 0.36	$ 2.69	$ 0.54
Weighted Average Common Shares Outstanding
Basic (in shares)	92,497	82,058	92,121	81,802
Diluted (in shares)	92,700	83,853	92,479	83,240
Oil and Condensate
Revenues	$ 245,212	$ 229,798	$ 447,956	$ 424,717
Natural Gas Liquids
Revenues	14,159	21,269	30,996	38,171
Natural Gas, Production
Revenues	$ 5,596	$ 12,906	$ 19,055	$ 26,365

Consolidated Statements Of Shar

Consolidated Statements Of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings (Accumulated Deficit) [Member]
BALANCE at Dec. 31, 2017	$ 370,897	$ 815	$ 1,926,056	$ (1,555,974)
BALANCE, shares at Dec. 31, 2017		81,454,621
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Loss on redemption of preferred stock	(7,100)
BALANCE at Mar. 31, 2018	391,281	$ 821	1,918,942	(1,528,482)
BALANCE, shares at Mar. 31, 2018		82,065,561
BALANCE at Dec. 31, 2017	370,897	$ 815	1,926,056	(1,555,974)
BALANCE, shares at Dec. 31, 2017		81,454,621
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	10,757		10,757
Issuance of common stock upon grants of restricted stock awards and vestings of restricted stock units and performance shares	(24)	$ 6	(30)
Issuance of common stock upon grants of restricted stock awards and vestings of restricted stock units and performance shares, net of forfeitures, shares		652,923
Dividends on preferred stock	(9,337)		(9,337)
Accretion on preferred stock	(1,493)		(1,493)
Loss on redemption of preferred stock	(7,133)		(7,133)
Net Income (loss)	62,801			62,801
BALANCE at Jun. 30, 2018	426,468	$ 821	1,918,820	(1,493,173)
BALANCE, shares at Jun. 30, 2018		82,107,544
BALANCE at Mar. 31, 2018	391,281	$ 821	1,918,942	(1,528,482)
BALANCE, shares at Mar. 31, 2018		82,065,561
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	5,110		5,110
Issuance of common stock upon grants of restricted stock awards and vestings of restricted stock units and performance shares	(18)	$ 0	(18)
Issuance of common stock upon grants of restricted stock awards and vestings of restricted stock units and performance shares, net of forfeitures, shares		41,983
Dividends on preferred stock	(4,474)		(4,474)
Accretion on preferred stock	(740)		(740)
Loss on redemption of preferred stock	0
Net Income (loss)	35,309			35,309
BALANCE at Jun. 30, 2018	426,468	$ 821	1,918,820	(1,493,173)
BALANCE, shares at Jun. 30, 2018		82,107,544
BALANCE at Dec. 31, 2018	980,904	$ 916	2,131,535	(1,151,547)
BALANCE, shares at Dec. 31, 2018		91,627,738
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	11,052		11,052
Issuance of common stock upon grants of restricted stock awards and vestings of restricted stock units and performance shares	0	$ 10	(10)
Issuance of common stock upon grants of restricted stock awards and vestings of restricted stock units and performance shares, net of forfeitures, shares		925,192
Dividends on preferred stock	(8,812)		(8,812)
Accretion on preferred stock	(1,634)		(1,634)
Loss on redemption of preferred stock	0
Net Income (loss)	258,848			258,848
BALANCE at Jun. 30, 2019	1,240,358	$ 926	2,132,131	(892,699)
BALANCE, shares at Jun. 30, 2019		92,552,930
BALANCE at Mar. 31, 2019	1,131,730	$ 925	2,130,989	(1,000,184)
BALANCE, shares at Mar. 31, 2019		92,503,562
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	6,428		6,428
Issuance of common stock upon grants of restricted stock awards and vestings of restricted stock units and performance shares	0	$ 1	(1)
Issuance of common stock upon grants of restricted stock awards and vestings of restricted stock units and performance shares, net of forfeitures, shares		49,368
Dividends on preferred stock	(4,452)		(4,452)
Accretion on preferred stock	(833)		(833)
Loss on redemption of preferred stock	0
Net Income (loss)	107,485			107,485
BALANCE at Jun. 30, 2019	$ 1,240,358	$ 926	$ 2,132,131	$ (892,699)
BALANCE, shares at Jun. 30, 2019		92,552,930

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Net Income (loss)	$ 258,848	$ 62,801
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation, depletion and amortization	156,088	136,897
(Gain) loss on derivatives, net	62,835	97,310
Cash paid for commodity derivative settlements, net	(7,160)	(38,448)
Loss on extinguishment of debt	0	8,676
Stock-based compensation expense, net	7,969	10,724
Deferred income tax (benefit) expense	(177,521)	529
Non-cash interest expense, net	1,271	1,262
Other, net	2,079	3,975
Changes in components of working capital and other assets and liabilities-
Accounts receivable	(7,824)	2,437
Accounts payable	(6,544)	3,878
Accrued liabilities	12,733	(12,883)
Other assets and liabilities, net	(978)	(1,286)
Net cash provided by operating activities	301,796	275,872
Cash Flows From Investing Activities
Capital expenditures	(362,478)	(430,639)
Acquisition of oil and gas properties	8,222	0
Proceeds from divestitures of oil and gas properties, net	6,034	345,789
Other, net	(38)	(1,096)
Net cash used in investing activities	(348,260)	(85,946)
Cash Flows From Financing Activities
Redemptions of senior notes	0	(330,435)
Redemption of preferred stock	0	(50,030)
Borrowings under credit agreement	898,890	1,126,856
Repayments of borrowings under credit agreement	(801,993)	(933,156)
Payments of credit facility amendment fees	(613)	(627)
Payments of dividends on preferred stock	(8,812)	(9,337)
Cash paid for settlements of contingent consideration arrangements, net	(40,000)	0
Other, net	(1,008)	(638)
Net cash provided by (used in) financing activities	46,464	(197,367)
Net Decrease in Cash and Cash Equivalents	0	(7,441)
Cash and Cash Equivalents, Beginning of Period	2,282	9,540
Cash and Cash Equivalents, End of Period	$ 2,282	$ 2,099

Nature Of Operations

Nature Of Operations	6 Months Ended
	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature Of Operations	1. Nature of Operations Carrizo Oil & Gas, Inc. is a Houston-based energy company which, together with its subsidiaries (collectively, the “Company” or “Carrizo”), is actively engaged in the exploration, development, and production of crude oil, NGLs, and natural gas from resource plays located in the United States. The Company’s current operations are principally focused in proven, producing oil and gas plays in the Eagle Ford Shale in South Texas and the Permian Basin in West Texas. Proposed Merger of the Company with Callon On July 14, 2019, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Callon Petroleum Company, a Delaware corporation (“Callon”). Pursuant to the Merger Agreement, the Company will be merged with and into Callon, with Callon continuing as the surviving entity (the “Merger”). The Merger was structured as a direct merger with the closing expected to occur in the fourth quarter of 2019. On and subject to the terms and conditions set forth in the Merger Agreement, upon closing of the Merger, each share of Carrizo’s common stock, par value $0.01 per share, issued and outstanding immediately prior to the effective time of the Merger will automatically be converted into the right to receive 2.05 shares of Callon’s common stock, par value $0.01 per share (the “Exchange Ratio”). Callon’s common stock is listed and traded on the New York Stock Exchange (the “NYSE”) under the ticker symbol CPE. Pursuant to the Merger Agreement, three members of the Company’s board of directors will become directors of Callon immediately after the effective time of the Merger. Pursuant to the terms of the Merger Agreement, each issued and outstanding share of the Company’s 8.875% redeemable preferred stock, par value $0.01 per share (the “Preferred Stock”), will either be converted into the right to receive one share of 8.875% redeemable preferred stock, par value $0.01 per share, of Callon, which will have substantially the same terms as the Preferred Stock or will be redeemed for an amount in cash specified in the Merger Agreement (the “Preferred Redemption”). Callon is obligated to deposit the amount required to effect the Preferred Redemption (the “Preferred Deposit”) no later than the open of business on the date of the closing of the Merger, though the Company is permitted to fund such amount if Callon fails to do so. In connection with the proposed Merger, restricted stock awards and units and performance shares that are outstanding immediately prior to closing will generally become vested and converted into shares of Callon common stock based on the Exchange Ratio. Stock appreciation rights that will be settled in cash (“Cash SARs”) that are outstanding immediately prior to the closing will be canceled and converted into a vested stock appreciation right covering shares of Callon common stock, with the calculation of such conversion described in the Merger Agreement. The completion of the Merger is subject to certain customary mutual closing conditions, including (i) the receipt of the required approvals from the shareholders of the Company and Callon, (ii) either (a) the approval by the holders of Preferred Stock or (b) the Preferred Deposit having been deposited and the Preferred Redemption having occurred, (iii) the expiration or termination of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the “HSR Act”), which was terminated effective August 6, 2019, and (iv) the receipt by each party of a customary opinion that the Merger will qualify as a “reorganization” within the meaning of Section 368(a) of the Internal Revenue Code of 1986. The obligation of each party to complete the Merger is also conditioned upon the other party’s representations and warranties being true and correct, subject to certain materiality exceptions, and the other party having performed in all material respects its obligations under the Merger Agreement. The Merger Agreement contains termination rights for each of the Company and Callon, including, among other things, (i) by either the Company or Callon if the other party’s board of directors changes its recommendation with respect to the transactions contemplated by the Merger Agreement or if the other party willfully breaches the covenant not to solicit alternative business combination proposals from third parties, (ii) by the Company, if its board of directors changes its recommendation with respect to the transactions contemplated by the Merger Agreement and substantially concurrently the Company enters into an acquisition agreement providing for a Company Superior Proposal, as defined in the Merger Agreement, (iii) by the Company or Callon, if the approvals of either their common shareholders shall not have been obtained, (iv) by the Company or Callon, if in certain circumstances, the other party breaches or fails to perform any of its representations, warranties or covenants in the Merger Agreement, and (v) by the Company or Callon, if the Merger shall not have been consummated by February 14, 2020, with a possible extension to April 14, 2020 in certain circumstances. Upon termination of the Merger Agreement under differing specified circumstances, (i) the Company would be required to pay Callon a termination fee of $47.4 million or to reimburse Callon up to $7.5 million in expenses or (ii) Callon would be required to pay the Company a termination fee of $57.0 million or to reimburse the Company up to $7.5 million in expenses. The capitalized terms which are not defined in this description of the proposed Merger, shall have the meaning given to such terms in the Merger Agreement. Additional information on the proposed Merger is included in the Form 8-K filed with the SEC on July 15, 2019 and in this Quarterly Report on Form 10-Q, including “Part II. Other Information—Item 1A. Risk Factors”.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Summary Of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation and Principles of Consolidation The accompanying unaudited interim consolidated financial statements include the accounts of the Company after elimination of intercompany transactions and balances and have been prepared pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (the “SEC”) and therefore do not include all disclosures required for financial statements prepared in conformity with accounting principles generally accepted in the U.S. (“GAAP”). In the opinion of management, these financial statements include all adjustments (consisting of normal recurring accruals and adjustments) necessary to present fairly, in all material respects, the Company’s interim financial position, results of operations and cash flows. However, the results of operations for the periods presented are not necessarily indicative of the results of operations that may be expected for the full year. Certain reclassifications have been made to prior period amounts to conform to the current period presentation. Such reclassifications had no material impact on prior period amounts. Significant Accounting Policies The Company’s significant accounting policies are described in “Note 2. Summary of Significant Accounting Policies” of the Notes to Consolidated Financial Statements in its Annual Report on Form 10-K for the year ended December 31, 2018 (“ 2018 Annual Report”) and are supplemented by the notes included in this Quarterly Report on Form 10-Q. The financial statements and related notes included in this report should be read in conjunction with the Company’s 2018 Annual Report. Recently Adopted Accounting Standards Leases. Effective January 1, 2019, the Company adopted ASU No. 2016-02, Leases (Topic 842) (“ASC 842”), using the modified retrospective approach and did not have a cumulative-effect adjustment in retained earnings as a result of the adoption. ASC 842 significantly changes accounting for leases by requiring that lessees recognize a liability representing the obligation to make lease payments and a related right-of-use (“ROU”) asset for virtually all lease transactions. However, ASC 842 does not apply to leases of mineral rights to explore for or use crude oil and natural gas. Upon adoption, the Company implemented policy elections and practical expedients which include the following: • package of practical expedients which allows the Company to avoid reassessing contracts that commenced prior to adoption that were properly evaluated under legacy lease accounting guidance; • excluding ROU assets and lease liabilities for leases with terms that are less than one year; • combining lease and non-lease components and accounting for them as a single lease (elected by asset class); • excluding land easements that existed or expired prior to adoption; and • policy election that eliminates the need for adjusting prior period comparable financial statements prepared under legacy lease accounting guidance. As a result of adopting ASC 842, the Company recorded lease liabilities of approximately $75.2 million and associated ROU assets of approximately $69.1 million on its consolidated balance sheets. The difference between the lease liabilities and ROU assets is due to a rent holiday and lease build-out incentives that were recorded as deferred lease liabilities under legacy lease accounting guidance. The adoption of ASC 842 did not materially change the Company’s consolidated statements of income or consolidated statements of cash flows. See “Note 6. Leases” for further discussion. Subsequent Events The Company evaluates subsequent events through the date the financial statements are issued. See “Note 16. Subsequent Events” for further discussion.

Revenue Recognition

Revenue Recognition	6 Months Ended
	Jun. 30, 2019
Revenue Recognition [Abstract]
Revenue from Contract with Customer [Text Block]	3. Revenue Recognition The Company’s revenues are comprised solely of revenues from customers and include the sale of crude oil, NGLs, and natural gas. The Company believes that the disaggregation of revenue into these three major product types appropriately depicts how the nature, amount, timing and uncertainty of revenue and cash flows are affected by economic factors based on its single geographic location. Crude oil, NGL, and natural gas revenues are recognized at a point in time when production is sold to a purchaser at a fixed or determinable price, delivery has occurred, control has transferred and collectability of the revenue is probable. The transaction price used to recognize revenue is a function of the contract billing terms. Revenue is invoiced by calendar month based on volumes at contractually based rates with payment typically required within 30 days of the end of the production month. At the end of each month when the performance obligation is satisfied, the variable consideration can be reasonably estimated and amounts due from customers are accrued in “Accounts receivable, net” in the consolidated balance sheets. As of June 30, 2019 and December 31, 2018 , receivables from contracts with customers were $76.9 million and $77.1 million , respectively. Taxes assessed by governmental authorities on crude oil, NGL, and natural gas sales are presented separately from such revenues in the consolidated statements of operations. Transaction Price Allocated to Remaining Performance Obligations

Acquisitions and Divestitures

Acquisitions and Divestitures	6 Months Ended
	Jun. 30, 2019
Acquisitions and Divestitures [Abstract]
Acquisition and Divestiture Disclosures	4. Acquisitions and Divestitures of Oil and Gas Properties 2019 Acquisitions and Divestitures The Company did not have any material acquisitions or divestitures for the three and six months ended June 30, 2019 . See “Note 1. Nature of Operations” for details of the proposed Merger which was announced on July 15, 2019. 2018 Acquisitions and Divestitures Devon Acquisition. On August 13, 2018, the Company entered into a purchase and sale agreement with Devon Energy Production Company, L.P. (“Devon”), a subsidiary of Devon Energy Corporation, to acquire oil and gas properties in the Delaware Basin in Reeves and Ward counties, Texas (the “Devon Properties”) for an agreed upon price of $215.0 million , with an effective date of April 1, 2018, subject to customary purchase price adjustments (the “Devon Acquisition”). The Company paid $21.5 million as a deposit on August 13, 2018, paid $183.4 million upon initial closing on October 17, 2018, and received $8.3 million as a post-closing adjustment on March 28, 2019, for an aggregate purchase price of $196.6 million . The Devon Acquisition was accounted for as a business combination, therefore, the purchase price was allocated to the assets acquired and the liabilities assumed based on their estimated acquisition date fair values based on then currently available information. A combination of a discounted cash flow model and market data was used by a third-party valuation specialist in determining the fair value of the oil and gas properties. Significant inputs into the calculation included future commodity prices, estimated volumes of oil and gas reserves, expectations for timing and amount of future development and operating costs, future plugging and abandonment costs and a risk adjusted discount rate. The following table presents the preliminary allocation of the purchase price to the assets acquired and liabilities assumed as of the acquisition date. Preliminary Purchase Price Allocation (In thousands) Assets Other current assets $216 Oil and gas properties Proved properties 47,118 Unproved properties 150,253 Total oil and gas properties $197,371 Total assets acquired $197,587 Liabilities Revenues and royalties payable $786 Asset retirement obligations 170 Total liabilities assumed $956 Net Assets Acquired $196,631 The results of operations for the Devon Acquisition have been included in the Company’s consolidated statements of income since the October 17, 2018 closing date, including total revenues and net income attributable to common shareholders for the three and six months ended June 30, 2019 as shown in the table below: Three Months Ended Six Months Ended (In thousands) Total revenues $4,342 $8,718 Net Income Attributable to Common Shareholders $2,020 $4,716 Eagle Ford Divestiture. On December 11, 2017, the Company entered into a purchase and sale agreement with EP Energy E&P Company, L.P. to sell a portion of its assets in the Eagle Ford Shale for an agreed upon price of $245.0 million , with an effective date of October 1, 2017, subject to adjustment and customary terms and conditions. The Company received $24.5 million as a deposit on December 11, 2017, $211.7 million upon closing on January 31, 2018, $10.0 million for leases that were not conveyed at closing on February 16, 2018, and paid $0.5 million as a post-closing adjustment on July 19, 2018, for aggregate net proceeds of $245.7 million . Niobrara Divestiture. On November 20, 2017, the Company entered into a purchase and sale agreement to sell substantially all of its assets in the Niobrara Formation for an agreed upon price of $140.0 million , with an effective date of October 1, 2017, subject to customary purchase price adjustments. The Company received $14.0 million as a deposit on November 20, 2017, $122.6 million upon closing on January 19, 2018, and paid $1.0 million as a post-closing adjustment on August 14, 2018, for aggregate net proceeds of $135.6 million . As part of this divestiture, the Company agreed to a contingent consideration arrangement (the “Contingent Niobrara Consideration”), which was determined to be an embedded derivative. See “Note 13. Derivative Instruments” and “Note 14. Fair Value Measurements” for further discussion. The aggregate net proceeds for each of the 2018 divestitures discussed above were recognized as a reduction of proved oil and gas properties with no gain or loss recognized.

Property And Equipment, Net

Property And Equipment, Net	6 Months Ended
	Jun. 30, 2019
Property, Plant and Equipment [Abstract]
Property And Equipment, Net	5. Property and Equipment, Net As of June 30, 2019 and December 31, 2018 , total property and equipment, net consisted of the following: June 30, December 31, (In thousands) Oil and gas properties, full cost method Proved properties $6,685,543 $6,278,321 Accumulated depreciation, depletion and amortization and impairments (4,098,202 ) (3,944,851 ) Proved properties, net 2,587,341 2,333,470 Unproved properties, not being amortized Unevaluated leasehold and seismic costs 580,369 608,830 Capitalized interest 76,607 65,003 Total unproved properties, not being amortized 656,976 673,833 Other property and equipment 30,580 29,191 Accumulated depreciation (19,392 ) (17,970 ) Other property and equipment, net 11,188 11,221 Total property and equipment, net $3,255,505 $3,018,524 Average depreciation, depletion and amortization (“DD&A”) per Boe of proved properties was $13.28 and $13.74 for the three months ended June 30, 2019 and 2018 , respectively, and $13.28 and $13.73 for the six months ended June 30, 2019 and 2018 , respectively. The Company capitalized internal costs of employee compensation and benefits, including stock-based compensation, directly associated with acquisition, exploration, and development activities totaling $3.8 million and $6.1 million for the three months ended June 30, 2019 and 2018 , respectively, and $12.9 million and $12.7 million for the six months ended June 30, 2019 and 2018 , respectively. Unproved properties, not being amortized, include unevaluated leasehold and seismic costs associated with specific unevaluated properties and related capitalized interest. The Company capitalized interest costs associated with its unproved properties totaling $8.6 million and $8.7 million for the three months ended June 30, 2019 and 2018 , respectively, and $17.6 million and $19.1 million for the six months ended June 30, 2019 and 2018

Leases

Leases	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Lessee, Operating Leases	6. Leases The Company determines if an arrangement is a lease at inception of the contract and, if the contract is determined to be a lease, classifies the lease as an operating or financing lease. The Company recognizes an operating or financing lease on its consolidated balance sheets as a lease liability, which represents the present value of the Company’s obligation to make lease payments arising from the lease, with a related ROU asset, which represents the Company’s right to use the underlying asset for the lease term. The Company’s operating leases typically do not provide an implicit interest rate, therefore, the Company utilizes its incremental borrowing rate to calculate the present value of the lease payments based on information available at inception of the contract. Lease expense for operating leases is recognized on a straight-line basis over the lease term. Lease expense for financing leases is comprised of interest expense on the financing lease liability and the amortization of the associated ROU asset, which is recognized on a straight-line basis over the lease term. Variable lease expense that is not dependent on an index or rate is not included in the operating or financing lease liability or ROU asset and is recognized in the period in which the obligation for those payments is incurred. Types of Leases The Company currently has leases associated with contracts for drilling rigs, office space, and the use of well equipment, vehicles, information technology infrastructure, and other office equipment, with the significant lease types described in more detail below. Drilling Rigs. The Company enters into contracts for drilling rigs with third parties to support its development plan. These contracts are typically for one to three years and can be extended upon mutual agreement with the third party by providing written notice at least thirty days prior to the end of the primary contractual term. The Company exercises its discretion in choosing whether or not to extend these contracts on a drilling rig by drilling rig basis as a result of evaluating the conditions that exist at the time the contract expires, such as availability of drilling rigs and the Company’s development plan. The Company has determined that it cannot conclude with reasonable certainty that it will choose to extend the contract past its primary term. As such, the Company uses the primary term in its calculation of the lease liability and ROU asset. The Company classifies its drilling rigs as operating leases and capitalizes the costs of the drilling rigs to oil and gas properties. Office Space . The Company leases office space from third parties for its corporate office and certain field locations. These leases have non-cancelable terms between one to fifteen years. The Company has determined that it cannot conclude with reasonable certainty that it will exercise any option to extend the contract past the non-cancelable term. As such, the Company uses the non-cancelable term in its calculation of the lease liability and ROU asset. The Company classifies its leases for office space as operating leases with the costs recognized as “General and administrative, net” in its consolidated statements of income. Well Equipment. The Company rents compressors from third parties to facilitate the flow of production from its drilling operations to market. These contracts range from less than one year to three years for the primary term and continue thereafter on a month to month basis subject to cancellation by either party with thirty days notice. The Company classifies the compressors as operating leases with a lease term equal to the primary term for those contracts that have a primary term greater than one year. After the primary term, each party has a substantive right to terminate the lease, therefore, enforceable rights and obligations do not exist subsequent to the primary term. For those contracts that are less than one year, the Company has concluded that they represent short-term operating leases and therefore, an operating lease liability and ROU asset is not recorded in the consolidated balance sheets. These lease payments are recognized as “Lease operating expense” in the Company’s statements of income. The tables below, which present the components of lease costs, supplemental balance sheet information, and supplemental cash flow information, are presented on a gross basis. Other joint owners in the properties operated by the Company generally pay for their working interest share of costs associated with drilling rigs and well equipment. The table below presents the components of the Company’s lease costs for the three and six months ended June 30, 2019 . Three Months Ended June 30, 2019 Six Months Ended June 30, 2019 (In thousands) Components of Lease Costs Finance lease costs Amortization of right-of-use assets (1) $410 $784 Interest on lease liabilities (2) 131 276 Operating lease costs (3) 8,700 22,780 Short-term lease costs (4) 245 463 Variable lease costs (5) 50 152 Total lease costs $9,536 $24,455 (1) Included as a component of “Depletion, depreciation and amortization” in the consolidated statements of income. (2) Included as a component of “Interest expense, net” in the consolidated statements of income. (3) For the three and six months ended June 30, 2019, approximately $6.1 million and $17.6 million are costs associated with drilling rigs and are capitalized to “Oil and gas properties” in the consolidated balance sheets and the other remaining operating lease costs are components of “General and administrative, net” and “Lease operating expense” in the consolidated statements of income. (4) Short-term lease costs are primarily associated with certain well equipment that have lease terms for less than one year and are components of “Lease operating expense” in the consolidated statements of income. (5) Variable lease costs include additional payments that were not included in the initial measurement of the lease liability and related ROU asset for lease agreements with terms greater than 12 months. Variable lease costs primarily consist of incremental usage associated with drilling rigs. The table below presents supplemental balance sheet information for the Company’s leases as of June 30, 2019 . June 30, 2019 (In thousands) Leases Operating leases: Operating lease ROU assets $64,615 Current operating lease liabilities $34,049 Long-term operating lease liabilities 36,526 Total operating lease liabilities $70,575 Financing leases: Other property and equipment, at cost $7,810 Accumulated depreciation (5,170 ) Other property and equipment, net $2,640 Current financing lease liabilities (1) $1,918 Long-term financing lease liabilities (2) 1,034 Total financing lease liabilities $2,952 (1) Included in “Other current liabilities” in the consolidated balance sheets. (2) Included in “Other long-term liabilities” in the consolidated balance sheets. The table below presents supplemental cash flow information for the Company’s leases for the six months ended June 30, 2019 . Six Months Ended June 30, 2019 (In thousands) Supplemental Cash Flow Information Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $5,338 Investing cash flows from operating leases $22,896 Operating cash flows from financing leases $276 Financing cash flows from financing leases $879 ROU assets obtained in exchange for lease liabilities Operating leases $9,404 Financing leases $1,082 The table below presents the weighted average remaining lease terms and weighted average discount rates for the Company’s leases as of June 30, 2019 . June 30, 2019 Weighted Average Remaining Lease Term (In years) Operating leases 5.1 years Financing leases 2.3 years Weighted Average Discount Rate Operating leases 8.0 % Financing leases 12.9 % The table below presents the maturity of the Company’s lease liabilities as of June 30, 2019 . Operating Leases Financing Leases (In thousands) July - December 2019 $20,842 $1,113 2020 27,856 1,475 2021 7,726 275 2022 3,697 234 2023 3,680 232 2024 and Thereafter 21,608 39 Total lease payments 85,409 3,368 Less: Imputed interest (14,834 ) (416 ) Total lease liabilities $70,575 $2,952

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	7. Income Taxes The Company’s estimated annual effective income tax rates are used to allocate expected annual income tax expense or benefit to interim periods. The rates are the ratio of estimated annual income tax expense or benefit to estimated annual income or loss before income taxes by taxing jurisdiction, excluding significant unusual or infrequent items, the tax effects of statutory rate changes, certain changes in the assessment of the realizability of deferred tax assets, and excess tax benefits or deficiencies related to the vesting of stock-based compensation awards, which are recognized as discrete items in the interim period in which they occur. The Company’s income tax (expense) benefit differed from the income tax (expense) benefit computed by applying the U.S. federal statutory corporate income tax rate of 21% for the three and six months ended June 30, 2019 and 2018 , to income before income taxes as follows: Three Months Ended June 30, Six Months Ended 2019 2018 2019 2018 (In thousands) Income before income taxes $109,784 $35,792 $81,752 $63,603 Income tax expense at the U.S. federal statutory rate (23,055 ) (7,517 ) (17,168 ) (13,357 ) State income tax expense, net of U.S. federal income tax benefit (874 ) (487 ) (626 ) (806 ) Tax deficiencies related to stock-based compensation (176 ) (16 ) (2,114 ) (2,542 ) (Recapture) release of valuation allowance (1,423 ) — 177,723 — Decrease in valuation allowance due to current period activity 23,211 8,048 19,273 16,449 Other 18 (511 ) 8 (546 ) Income tax (expense) benefit ($2,299 ) ($483 ) $177,096 ($802 ) Deferred Tax Asset Valuation Allowance The deferred tax asset valuation allowance was $45.9 million and $242.9 million as of June 30, 2019 and December 31, 2018 , respectively. Throughout 2018, the Company maintained a full valuation allowance against its deferred tax assets based on its conclusion, considering all available evidence (both positive and negative), that it was more likely than not that the deferred tax assets would not be realized. A significant item of objective negative evidence considered was the cumulative pre-tax loss incurred over the three-year period ended December 31, 2018, primarily due to impairments of proved oil and gas properties recognized in the first three quarters of 2016. As of March 31, 2019 and June 30, 2019, the Company is in a cumulative three-year pre-tax income position. Based on this factor, as well as other positive evidence including projected future taxable income for the current and future years, the Company concluded that it is more likely than not that the deferred tax assets would be realized and released $179.1 million of the valuation allowance during the first quarter of 2019. During the second quarter of 2019, the Company reduced the prior valuation allowance release by $1.4 million as a result of updating the Company’s forecasted taxable income for 2019 bringing the cumulative release of the valuation allowance to $177.7 million . The reduction of the release of the valuation allowance in the second quarter of 2019 is recognized as a decrease in deferred tax assets and an increase in income tax expense, while the cumulative release of the valuation allowance for the six months ended June 30, 2019 is recognized as an increase in deferred tax assets and an income tax benefit.

Long-Term Debt

Long-Term Debt	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Debt	8. Long-Term Debt Long-term debt consisted of the following as of June 30, 2019 and December 31, 2018 : June 30, December 31, (In thousands) Senior Secured Revolving Credit Facility due 2022 $841,328 $744,431 6.25% Senior Notes due 2023 650,000 650,000 Unamortized debt issuance costs for 6.25% Senior Notes (6,180 ) (6,878 ) 8.25% Senior Notes due 2025 250,000 250,000 Unamortized debt issuance costs for 8.25% Senior Notes (3,730 ) (3,962 ) Long-term debt $1,731,418 $1,633,591 Senior Secured Revolving Credit Facility The Company has a senior secured revolving credit facility with a syndicate of banks that, as of June 30, 2019 , had a borrowing base of $1.35 billion , with an elected commitment amount of $1.25 billion , and borrowings outstanding of $841.3 million at a weighted average interest rate of 4.14% . The credit agreement governing the revolving credit facility provides for interest-only payments until May 4, 2022, when the credit agreement matures and any outstanding borrowings are due. The borrowing base under the credit agreement is subject to regular redeterminations in the spring and fall of each year, as well as special redeterminations described in the credit agreement, which in each case may reduce the amount of the borrowing base. The amount the Company is able to borrow with respect to the borrowing base is subject to compliance with the financial covenants and other provisions of the credit agreement. The capitalized terms which are not defined in this description of the revolving credit facility, shall have the meaning given to such terms in the credit agreement. On March 27, 2019, the Company entered into the fourteenth amendment to its credit agreement governing the revolving credit facility to, among other things (i) establish the borrowing base at $1.35 billion , with an elected commitment amount of $1.25 billion , until the next redetermination thereof, (ii) amend the definition of Current Ratio, and (iii) amend certain other definitions and provisions. The obligations of the Company under the credit agreement are guaranteed by the Company’s material subsidiaries and are secured by liens on substantially all of the Company’s assets, including a mortgage lien on oil and gas properties having at least 90% of the total value of the oil and gas properties included in the Company’s reserve report used in its most recent redetermination. Borrowings outstanding under the credit agreement bear interest at the Company’s option at either (i) a base rate for a base rate loan plus the margin set forth in the table below, where the base rate is defined as the greatest of the prime rate, the federal funds rate plus 0.50% and the adjusted LIBO rate plus 1.00% , or (ii) an adjusted LIBO rate for a Eurodollar loan plus the margin set forth in the table below. The Company also incurs commitment fees at rates as set forth in the table below on the unused portion of lender commitments, which are included in “Interest expense, net” in the consolidated statements of income. Ratio of Outstanding Borrowings to Lender Commitments Applicable Margin for Base Rate Loans Applicable Margin for Eurodollar Loans Commitment Fee Less than 25% 0.25% 1.25% 0.375% Greater than or equal to 25% but less than 50% 0.50% 1.50% 0.375% Greater than or equal to 50% but less than 75% 0.75% 1.75% 0.500% Greater than or equal to 75% but less than 90% 1.00% 2.00% 0.500% Greater than or equal to 90% 1.25% 2.25% 0.500% The Company is subject to certain covenants under the terms of the credit agreement, which include the maintenance of the following financial covenants determined as of the last day of each quarter: (1) a ratio of Total Debt to EBITDA of not more than 4.00 to 1.00 and (2) a Current Ratio of not less than 1.00 to 1.00. As defined in the credit agreement, Total Debt excludes debt issuance costs and is net of cash and cash equivalents, EBITDA is calculated based on the last four fiscal quarters after giving pro forma effect to EBITDA for material acquisitions and divestitures of oil and gas properties, and the Current Ratio includes an add back of the unused portion of lender commitments and excludes the Contingent ExL Consideration, which is described in “Note 13. Derivative Instruments.” As of June 30, 2019 , the ratio of Total Debt to EBITDA was 2.40 to 1.00 and the Current Ratio was 1.73 to 1.00. Because the financial covenants are determined as of the last day of each quarter, the ratios can fluctuate significantly period to period as the level of borrowings outstanding under the credit agreement are impacted by the timing of cash flows from operations, capital expenditures, acquisitions and divestitures of oil and gas properties and securities offerings. The credit agreement also places restrictions on the Company and certain of its subsidiaries with respect to additional indebtedness, liens, dividends and other payments to shareholders, repurchases or redemptions of the Company’s common stock, redemptions of senior notes, investments, acquisitions and divestitures of oil and gas properties, mergers, transactions with affiliates, hedging transactions and other matters. Due to the proposed Merger, our regular redetermination scheduled for the fall of 2019 was postponed to occur on or about February 14, 2020. Senior Notes During the first quarter of 2018, the Company redeemed $320.0 million of the outstanding aggregate principal amount of its 7.50% Senior Notes at a price equal to 101.875% of par. The Company paid a total of $336.9 million upon the redemptions, which included redemption premiums of $6.0 million and accrued and unpaid interest of $10.9 million . The redemptions were funded primarily from the net proceeds received from the divestitures in Eagle Ford and Niobrara in the first quarter of 2018. See “Note 4. Acquisitions and Divestitures of Oil and Gas Properties” for further details of these divestitures. As a result of the redemptions, the Company recorded a loss on extinguishment of debt of $8.7 million , which included the redemption premiums of $6.0 million and the write-off of associated unamortized premiums and debt issuance costs of $2.7 million . On May 3, 2018, the Company redeemed the remaining $4.4 million outstanding aggregate principal amount of its 4.375% Convertible Senior Notes due 2028 at a price equal to 100% of par. Upon the redemption, the Company paid $4.5 million , which included accrued and unpaid interest of $0.1 million . Subsidiary Guarantors The Company’s Senior Notes are guaranteed by its subsidiary guarantors, which are all 100% owned by the parent company. The guarantees are full and unconditional and joint and several. Carrizo Oil & Gas, Inc., as the parent company, has no independent assets and operations. Any subsidiaries of the parent company, other than the subsidiary guarantors, are minor. In addition, there are no significant restrictions on the ability of the parent company or any guarantor to obtain funds from its subsidiaries by dividend or loan.

Commitments And Contingencies

Commitments And Contingencies	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	9. Commitments and Contingencies From time to time, the Company is party to certain legal actions and claims arising in the ordinary course of business. While the outcome of these events cannot be predicted with certainty, management does not currently expect these matters to have a materially adverse effect on the financial position or results of operations of the Company. The results of operations and financial position of the Company continue to be affected from time to time in varying degrees by domestic and foreign political developments as well as legislation and regulations pertaining to restrictions on oil and gas production, imports and exports, tax changes, environmental regulations and cancellation of contract rights. Both the likelihood and overall effect of such occurrences on the Company vary greatly and are not predictable.

Preferred Stock

Preferred Stock	6 Months Ended
	Jun. 30, 2019
Preferred Stock [Abstract]
Preferred Stock	10. Preferred Stock and Common Stock Warrants See “Note 1. Nature of Operations” for discussion of the impact to the Preferred Stock as a result of the proposed Merger. On August 10, 2017, the Company closed on the issuance and sale in a private placement of (i) $250.0 million initial liquidation preference ( 250,000 shares) of Preferred Stock and (ii) warrants for 2,750,000 shares of the Company’s common stock, with a term of ten years and an exercise price of $16.08 per share, exercisable only on a net share settlement basis (the “Warrants”), for a cash purchase price equal to $970.00 per share of Preferred Stock, to certain funds managed or sub-advised by GSO Capital Partners LP and its affiliates. The Preferred Stock is presented as temporary equity in the consolidated balance sheets with the issuance date fair value accreted to the initial liquidation preference using the effective interest method. The Warrants are presented in “Additional paid-in capital” in the consolidated balance sheets at their issuance date fair value. The Preferred Stock has a liquidation preference of $1,000.00 per share and bears an annual cumulative dividend rate of 8.875% , payable on March 15, June 15, September 15 and December 15 of any given year. The Company may elect to pay a portion of the Preferred Stock dividends in shares of its common stock in decreasing percentages as follows with respect to any preferred stock dividend declared by the Company’s Board of Directors and paid in respect of a quarter ending: Period Percentage On or after December 15, 2018 and on or prior to September 15, 2019 75 % On or after December 15, 2019 and on or prior to September 15, 2020 50 % If the Company fails to satisfy the Preferred Stock dividend on the applicable dividend payment date, then the unpaid dividend will be added to the liquidation preference until paid. The table below sets forth a reconciliation of changes in the carrying amount of Preferred Stock for the six months ended June 30, 2019 and 2018 . Six Months Ended June 30, 2019 2018 (In thousands) Preferred Stock, beginning of period $174,422 $214,262 Redemption of Preferred Stock — (42,897 ) Accretion on Preferred Stock 1,634 1,493 Preferred Stock, end of period $176,056 $172,858 Loss on Redemption of Preferred Stock On or prior to August 10, 2018, the Company had the right to redeem up to 50,000 shares of Preferred Stock, in cash, at $1,000.00 per share, plus accrued and unpaid dividends in an amount not to exceed the sum of the cash proceeds of divestitures of oil and gas properties and related assets, the sale or issuance of the Company’s common stock and the sale of any of the Company’s wholly owned subsidiaries. During the first quarter of 2018, the Company redeemed 50,000 shares of Preferred Stock, representing 20% of the issued and outstanding Preferred Stock, for $50.5 million , consisting of the $50.0 million redemption price and accrued and unpaid dividends of $0.5 million . The Company recognized a $7.1 million loss on the redemption due to the excess of the $50.0 million redemption price over the $42.9 million

Shareholders' Equity and Stock

Shareholders' Equity and Stock Incentive Plans	6 Months Ended
	Jun. 30, 2019
Shareholders' Equity and Stock Incentive Plans [Abstract]
Shareholders' Equity and Share-based Payments	11. Stock-Based Compensation See “Note 1. Nature of Operations” for discussion of the impact to the Company’s restricted stock awards and units, performance shares, and Cash SARs as a result of the proposed Merger. At the Company’s annual meeting on May 16, 2019, the shareholders approved the proposal to amend and restate the 2017 Incentive Plan of Carrizo Oil & Gas, Inc. (the “A&R 2017 Incentive Plan”),which included an increase to the number of shares available for issuance under the A&R 2017 Incentive Plan. As of June 30, 2019 , there were 3,164,691 shares of common stock available for grant under the A&R 2017 Incentive Plan assuming all future grants will be full value stock awards. The Company has not granted stock appreciation rights to be settled in shares of common stock and has no outstanding stock options. See “Note 11. Stock-Based Compensation” of the Notes to Consolidated Financial Statements in the 2018 Annual Report for details of the Company’s equity-based incentive plans. Restricted Stock Awards and Units The table below summarizes restricted stock award and unit activity for the three and six months ended June 30, 2019 and 2018 : Three Months Ended June 30, 2019 2018 Restricted Stock Awards and Units Weighted Average Grant Date Fair Value Restricted Stock Awards and Units Weighted Average Grant Date Unvested, beginning of period 3,320,060 $14.16 2,263,830 $19.15 Granted 115,936 $11.90 1,250 $15.43 Vested (52,639 ) $25.20 (43,992 ) $25.76 Forfeited (47,464 ) $12.05 (9,915 ) $18.04 Unvested, end of period 3,335,893 $13.94 2,211,173 $19.02 Six Months Ended June 30, 2019 2018 Restricted Stock Awards and Units Weighted Average Grant Date Fair Value Restricted Stock Awards and Units Weighted Average Grant Date Unvested, beginning of period 2,266,667 $19.28 1,482,655 $28.07 Granted 2,034,619 $11.06 1,348,415 $14.68 Vested (904,973 ) $20.91 (608,904 ) $31.43 Forfeited (60,420 ) $13.14 (10,993 ) $19.17 Unvested, end of period 3,335,893 $13.94 2,211,173 $19.02 Grant activity for the three months ended June 30, 2019 primarily consisted of restricted stock units to non-employee directors for their service for the 2019-2020 director term. These grants to the non-employee directors vest on the earlier of the date of the 2020 Annual Meeting of Shareholders and June 30, 2020. Grant activity for the six months ended June 30, 2019 primarily consisted of restricted stock units to employees as part of the annual grant of long-term equity incentive awards that occurred in the first quarter of each of the years presented in the table above. These restricted stock units vest ratably over an approximate three -year period. As a result of the approval of the A&R 2017 Incentive Plan by shareholders, the Compensation Committee determined that the Company would settle the restricted stock units granted in the first quarter of 2019 in common stock rather than cash upon vesting. As such, the Company modified these restricted stock units, which were previously accounted for as liability awards to equity awards and reclassified the fair value of these awards to shareholders’ equity in the consolidated balance sheets. The aggregate fair value of restricted stock awards and units that vested during the three months ended June 30, 2019 and 2018 was $0.7 million and $1.0 million , respectively, and $10.5 million and $9.9 million for the six months ended June 30, 2019 and 2018 , respectively. As of June 30, 2019 and 2018 , unrecognized compensation costs related to unvested restricted stock awards and units were $38.3 million and $30.5 million , respectively, to be recognized over a weighted average period of 2.2 years. Cash SARs There was no activity for Cash SARs for the three months ended June 30, 2019 and 2018 . The table below summarizes the activity for Cash SARs for the six months ended June 30, 2019 and 2018 : Six Months Ended June 30, 2019 2018 Cash SARs Weighted Average Exercise Prices Weighted Average Remaining Life (In years) Cash SARs Weighted Weighted Average Remaining Life Outstanding, beginning of period 1,330,924 $21.35 714,238 $27.12 Granted 770,775 $10.98 616,686 $14.67 Exercised — $— — $— Forfeited — $— — $— Expired — $— — $— Outstanding, end of period 2,101,699 $17.55 4.9 1,330,924 $21.35 4.8 Vested, end of period 919,800 $24.34 543,018 $27.18 Vested and exercisable, end of period — $24.34 3.0 543,018 $27.18 3.0 Grant activity consisted of Cash SARs to certain employees as part of the annual grant of long-term equity incentive awards that occurred in the first quarter of each of the years presented in the table above. The Cash SARs granted in the first quarter of 2019 and 2018 vest ratably over an approximate three -year period and expire approximately seven years from the grant date. The grant date fair value of the Cash SARs, calculated using the Black-Scholes-Merton option pricing model, was $4.6 million and $4.9 million for the six months ended June 30, 2019 and 2018 . The following table summarizes the assumptions used and the resulting grant date fair value of the Cash SARs granted during the six months ended June 30, 2019 and 2018 : Six Months Ended June 30, 2019 2018 Expected term (in years) 6.1 6.0 Expected volatility 56.0 % 54.3 % Risk-free interest rate 2.6 % 2.8 % Dividend yield — % — % Grant date fair value per Cash SAR $6.00 $7.89 The aggregate intrinsic value of Cash SARs outstanding as of June 30, 2019 and 2018 was zero and $9.1 million , respectively, and the aggregate intrinsic value of Cash SARs vested and exercisable as of June 30, 2019 and 2018 was zero and $0.5 million . As of June 30, 2019 and December 31, 2018 , the liabilities for Cash SARs were $2.1 million and $1.8 million , all of which was classified as “Other current liabilities,” in the respective consolidated balance sheets. As of June 30, 2019 and 2018 , unrecognized compensation costs related to unvested Cash SARs were $5.1 million and $11.3 million , respectively, to be recognized over a weighted average period of 2.4 years and 2.6 years, respectively. Performance Shares There was no performance share activity for the three months ended June 30, 2019 and 2018 . The table below summarizes performance share activity for the six months ended June 30, 2019 and 2018 : Six Months Ended June 30, 2019 2018 Target Performance Shares (1) Weighted Average Grant Date Fair Value Target Performance Shares (1) Weighted Average Grant Date Unvested, beginning of period 182,209 $27.01 144,955 $47.14 Granted 130,302 $14.20 93,771 $19.09 Vested at end of performance period (31,244 ) $35.71 (49,458 ) $65.51 Did not vest at end of performance period (10,407 ) $35.71 (7,059 ) $65.51 Forfeited — $— — $— Unvested, end of period 270,860 $19.51 182,209 $27.01 (1) The number of performance shares that vest may vary from the number of target performance shares granted depending on the Company ’ s final TSR ranking for the approximate three -year performance period. Grant activity consisted of performance shares as part of the annual grant of long-term equity incentive awards to certain employees that occurred in the first quarter of 2019 and 2018. Each performance share represents the right to receive one share of common stock, however, the number of performance shares that vest ranges from zero to 200% of the target performance shares granted based on the total shareholder return (“TSR”) of the Company’s common stock relative to the TSR achieved by a specified industry peer group over an approximate three -year performance period, the last day of which is also the vesting date. The following table presents the results of the Company’s final TSR ranking during the performance periods that ended during the six months ended June 30, 2019 and 2018 : Six Months Ended June 30, 2019 2018 Target performance shares granted 41,651 56,517 Multiplier 75 % 88 % Performance shares vested 31,244 49,458 Performance shares that did not vest 10,407 7,059 Aggregate fair value of performance shares vested (In millions) $0.4 $0.8 For the six months ended June 30, 2019 and 2018 , the grant date fair value of the performance shares, calculated using a Monte Carlo simulation, was $1.9 million and $1.8 million , respectively. The following table summarizes the assumptions used and the resulting grant date fair value per performance share for the grant activity during the six months ended June 30, 2019 : Six Months Ended June 30, 2019 2018 Number of simulations 500,000 500,000 Expected term (in years) 3.1 3.0 Expected volatility 58.2 % 61.5 % Risk-free interest rate 2.5 % 2.4 % Dividend yield — % — % Grant date fair value per performance share $14.20 $19.09 As of June 30, 2019 and 2018 , unrecognized compensation costs related to unvested performance shares were $3.1 million and $2.9 million , respectively, to be recognized over a weighted average period of 2.1 years and 2.2 years, respectively. Stock-Based Compensation Expense, Net Stock-based compensation expense associated with restricted stock awards and units, Cash SARs, and performance shares, net of amounts capitalized, is included in “General and administrative, net” in the consolidated statements of income. The Company recognized the following stock-based compensation expense, net for the three and six months ended June 30, 2019 and 2018 : Three Months Ended June 30, Six Months Ended 2019 2018 2019 2018 (In thousands) Restricted stock awards and units $5,358 $4,720 $10,181 $9,804 Cash SARs (426 ) 5,788 334 4,373 Performance shares 436 406 871 963 5,368 10,914 11,386 15,140 Less: amounts capitalized to oil and gas properties (1,514 ) (3,708 ) (3,417 ) (4,416 ) Total stock-based compensation expense, net $3,854 $7,206 $7,969 $10,724

Earnings per Share

Earnings per Share	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Earnings Per Share	12. Net Income Attributable to Common Shareholders Per Common Share The following table summarizes the calculation of net income attributable to common shareholders per common share: Three Months Ended June 30, Six Months Ended 2019 2018 2019 2018 (In thousands, except per share amounts) Net Income $107,485 $35,309 $258,848 $62,801 Dividends on preferred stock (4,452 ) (4,474 ) (8,812 ) (9,337 ) Accretion on preferred stock (833 ) (740 ) (1,634 ) (1,493 ) Loss on redemption of preferred stock — — — (7,133 ) Net Income Attributable to Common Shareholders $102,200 $30,095 $248,402 $44,838 Basic weighted average common shares outstanding 92,497 82,058 92,121 81,802 Dilutive effect of restricted stock and performance shares 203 967 358 798 Dilutive effect of common stock warrants — 828 — 640 Diluted weighted average common shares outstanding 92,700 83,853 92,479 83,240 Net Income Attributable to Common Shareholders Per Common Share Basic $1.10 $0.37 $2.70 $0.55 Diluted $1.10 $0.36 $2.69 $0.54 The computation of diluted net income attributable to common shareholders per common share excluded restricted stock, performance shares and common stock warrants that were anti-dilutive. The following table presents the weighted average anti-dilutive securities for the periods presented: Three Months Ended June 30, Six Months Ended 2019 2018 2019 2018 (In thousands) Anti-dilutive restricted stock and performance shares 3,077 16 1,526 19 Anti-dilutive common stock warrants 2,750 — 2,750 — Total weighted average anti-dilutive securities 5,827 16 4,276 19

Derivative Instruments

Derivative Instruments	6 Months Ended
	Jun. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	13. Derivative Instruments Commodity Derivative Instruments The Company uses commodity derivative instruments to mitigate the effects of commodity price volatility for a portion of its forecasted sales of production and achieve a more predictable level of cash flow. Since the Company derives a significant portion of its revenues from sales of crude oil, crude oil price volatility represents the Company’s most significant commodity price risk. While the use of commodity derivative instruments limits or partially reduces the downside risk of adverse commodity price movements, such use also limits the upside from favorable commodity price movements. The Company does not enter into commodity derivative instruments for speculative purposes. The Company’s commodity derivative instruments, which settle on a monthly basis over the term of the contract for contracted volumes, consist of over-the-counter price swaps, three-way collars, sold call options, and basis swaps, each of which is described below. Price swaps are settled based on differences between a fixed price and the settlement price of a referenced index. If the settlement price of the referenced index is below the fixed price, the Company receives the difference from the counterparty. If the referenced settlement price is above the fixed price, the Company pays the difference to the counterparty. Three-way collars consist of a purchased put option (floor price), a sold call option (ceiling price) and a sold put option (sub-floor price) and are settled based on differences between the floor or ceiling prices and the settlement price of a referenced index or the difference between the floor price and sub-floor price. If the settlement price of the referenced index is below the sub-floor price, the Company receives the difference between the floor price and sub-floor price from the counterparty. If the settlement price of the referenced index is between the floor price and sub-floor price, the Company receives the difference between the floor price and the settlement price of the referenced index from the counterparty. If the settlement price of the referenced index is between the floor price and ceiling price, no payments are due to or from either party. If the settlement price of the referenced index is above the ceiling price, the Company pays the difference to the counterparty. Sold call options are settled based on differences between the ceiling price and the settlement price of a referenced index. If the settlement price of the referenced index is above the ceiling price, the Company pays the difference to the counterparty. If the settlement price of the referenced index is below the ceiling price, no payments are due to or from either party. Premiums from the sale of call options have been used to enhance the fixed price of certain contemporaneously executed price swaps. Purchased call options executed contemporaneously with sold call options in order to increase the ceiling price of existing sold call options have been presented on a net basis in the table below. Basis swaps are settled based on differences between a fixed price differential and the differential between the settlement prices of two referenced indexes. If the differential between the settlement prices of the two referenced indexes is greater than the fixed price differential, the Company receives the difference from the counterparty. If the differential between the settlement prices of the two referenced indexes is less than the fixed price differential, the Company pays the difference to the counterparty. The referenced index of the Company’s price swaps, three-way collars, and sold call options is U.S. New York Mercantile Exchange (“NYMEX”) West Texas Intermediate (“WTI”) for crude oil and NYMEX Henry Hub for natural gas, as applicable. The index price the Company receives on its crude oil basis swaps is Argus WTI Cushing (“WTI Cushing”) plus or minus a fixed price differential and the index price it pays is Argus WTI Midland (“WTI Midland”) or Argus Light Louisiana Sweet (“LLS”). The index price the Company receives on its natural gas basis swaps is NYMEX Henry Hub minus a fixed price differential and the index price it pays is Platt’s Inside FERC West Texas Waha (“Waha”). The Company has incurred premiums on certain of its commodity derivative instruments in order to obtain a higher floor price and/or higher ceiling price. Payment of these premiums are deferred until the applicable contracts settle on a monthly basis over the term of the contract or, in some cases, during the final 12 months of the contract and are referred to as deferred premium obligations. As of June 30, 2019 , the Company had the following outstanding commodity derivative instruments at weighted average contract volumes and prices: Commodity Period Type of Contract Index Volumes (Bbls per day) Fixed Price ($ per Bbl) Sub-Floor Price ($ per Bbl) Floor Price ($ per Bbl) Ceiling Price ($ per Bbl) Fixed Price Differential ($ per Bbl) Crude oil 3Q19 Price Swaps NYMEX WTI 5,000 $64.80 — — — — Crude oil 3Q19 Three-Way Collars NYMEX WTI 27,000 — $41.67 $50.96 $74.23 — Crude oil 3Q19 Basis Swaps LLS-WTI Cushing 6,000 — — — — $5.16 Crude oil 3Q19 Basis Swaps WTI Midland-WTI Cushing 9,100 — — — — ($4.44 ) Crude oil 3Q19 Sold Call Options NYMEX WTI 3,875 — — — $81.07 — Crude oil 4Q19 Price Swaps NYMEX WTI 5,000 $64.80 — — — — Crude oil 4Q19 Three-Way Collars NYMEX WTI 27,000 — $41.67 $50.96 $74.23 — Crude oil 4Q19 Basis Swaps WTI Midland-WTI Cushing 9,200 — — — — ($4.64 ) Crude oil 4Q19 Sold Call Options NYMEX WTI 3,875 — — — $81.07 — Crude oil 2020 Price Swaps NYMEX WTI 3,000 $55.06 — — — — Crude oil 2020 Three-Way Collars NYMEX WTI 12,000 — $45.63 $55.63 $66.04 — Crude oil 2020 Basis Swaps WTI Midland-WTI Cushing 10,658 — — — — ($1.68 ) Crude oil 2020 Sold Call Options NYMEX WTI 4,575 — — — $75.98 — Crude oil 2021 Basis Swaps WTI Midland-WTI Cushing 8,000 — — — — $0.18 Commodity Period Type of Contract Index Volumes (MMBtu per day) Fixed Price ($ per MMBtu) Sub-Floor Price ($ per MMBtu) Floor Price ($ per MMBtu) Ceiling Price ($ per MMBtu) Fixed Price Differential ($ per MMBtu) Natural gas 3Q19 Basis Swaps Waha-NYMEX Henry Hub 42,500 — — — — ($1.49 ) Natural gas 3Q19 Sold Call Options NYMEX Henry Hub 33,000 — — $3.25 — Natural gas 4Q19 Basis Swaps Waha-NYMEX Henry Hub 42,500 — — — — ($1.30 ) Natural gas 4Q19 Sold Call Options NYMEX Henry Hub 33,000 — — $3.25 — Natural gas 2020 Basis Swaps Waha-NYMEX Henry Hub 29,541 — — — — ($0.77 ) Natural gas 2020 Sold Call Options NYMEX Henry Hub 33,000 — — $3.50 — The Company typically has numerous commodity derivative instruments outstanding with a counterparty that were executed at various dates, for various contract types, commodities and time periods often resulting in both commodity derivative asset and liability positions with that counterparty. The Company nets its commodity derivative instrument fair values executed with the same counterparty, along with any deferred premium obligations, to a single asset or liability pursuant to International Swap Dealers Association Master Agreements (“ISDAs”), which provide for net settlement over the term of the contract and in the event of default or termination of the contract. Counterparties to the Company’s commodity derivative instruments who are also lenders under the Company’s credit agreement (“Lender Counterparty”) allow the Company to satisfy any need for margin obligations associated with commodity derivative instruments where the Company is in a net liability position with the Lender Counterparty with the collateral securing the credit agreement, thus eliminating the need for independent collateral posting. Counterparties to the Company’s commodity derivative instruments who are not lenders under the Company’s credit agreement (“Non-Lender Counterparty”) can require commodity derivative instruments to be novated to a Lender Counterparty if the Company’s net liability position exceeds the Company’s unsecured credit limit with the Non-Lender Counterparty and therefore do not require the posting of cash collateral. Because each Lender Counterparty has an investment grade credit rating and the Company has obtained a guaranty from each Non-Lender Counterparty’s parent company which has an investment grade credit rating, the Company believes it does not have significant credit risk and accordingly does not currently require its counterparties to post collateral to support the net asset positions of its commodity derivative instruments. Although the Company does not currently anticipate nonperformance from its counterparties, it continually monitors the credit ratings of each Lender Counterparty and each Non-Lender Counterparty’s parent company. As of June 30, 2019, the Company has outstanding commodity derivative instruments with fifteen counterparties to minimize its credit exposure to any individual counterparty. Contingent Consideration Arrangements The purchase and sale agreements for the acquisition of properties in the Delaware Basin from ExL Petroleum Management, LLC and ExL Petroleum Operating Inc. (the “ExL Acquisition”) in 2017 and divestitures of the Company’s assets in the Niobrara in 2018, and Marcellus and Utica in 2017, included contingent consideration arrangements that require the Company to pay or entitle the Company to receive specified amounts if commodity prices exceed specified thresholds, which are summarized in the tables below. If the pricing threshold for the respective contingent consideration arrangement is met, the payment is made or received in the first quarter of the following year. See “Note 3. Acquisitions and Divestitures of Oil and Gas Properties” of the Notes to Consolidated Financial Statements in the 2018 Annual Report for further discussion of these transactions. See “—Cash received (paid) for settlements of contingent consideration arrangements, net” below for discussion of the settlements that occurred during the first quarter of 2019. Contingent ExL Consideration Year Threshold (1) Period Cash Flow Occurs Statement of Cash Flows Presentation Contingent Payment - Annual Remaining Contingent Payments - Aggregate Limit Acquisition Date Fair Value (In thousands) ($52,300 ) Actual Settlement 2018 $50.00 1Q19 Financing ($50,000 ) Remaining Potential Settlements 2019-2021 50.00 (2) (2) (50,000 ) ($75,000 ) (1) The price used to determine whether the specified threshold for each year has been met is the average daily closing spot price per barrel of WTI crude oil as measured by the U.S. Energy Information Administration (“U.S. EIA”). (2) Cash paid for settlements of contingent consideration arrangements are classified as cash flows from financing activities up to the acquisition date fair value with any excess classified as cash flows from operating activities. Therefore, if the commodity price threshold is reached, $2.3 million of the next contingent payment will be presented in cash flows from financing activities with the remainder, as well as all subsequent contingent payments, presented in cash flows from operating activities. Contingent Niobrara Consideration Year Threshold (1) Period Cash Flow Occurs Statement of Cash Flows Presentation Contingent Receipt - Annual Remaining Contingent Payments - Aggregate Limit Divestiture Date Fair Value (In thousands) $7,880 Actual Settlement 2018 $55.00 1Q19 Financing $5,000 Remaining Potential Settlements 2019 55.00 1Q20 (2) 5,000 $10,000 2020 60.00 1Q21 (2) 5,000 (1) The price used to determine whether the specified threshold for each year has been met is the average daily closing spot price per barrel of WTI crude oil as measured by the U.S. EIA. (2) If the commodity price threshold is reached, $2.9 million of the next contingent receipt will be presented in cash flows from financing activities with the remainder, as well as all subsequent contingent receipts, presented in cash flows from operating activities. Contingent Marcellus Consideration Year Threshold (1) Period Cash Flow Occurs Statement of Cash Flows Presentation Contingent Receipt - Annual Remaining Contingent Payments - Aggregate Limit Divestiture Date Fair Value (In thousands) $2,660 Actual Settlement 2018 $3.13 1Q19 N/A $— Remaining Potential Settlements 2019 3.18 1Q20 (2) 3,000 $6,000 2020 3.30 1Q21 (2) 3,000 (1) The price used to determine whether the specified threshold for each year has been met is the average monthly settlement price per MMBtu of Henry Hub natural gas for the next calendar month, as determined on the last business day preceding each calendar month as measured by the CME Group Inc. (2) For the first quarter of 2019 , there was no settlement for the Contingent Marcellus Consideration. Therefore, if the commodity price threshold is reached, $2.7 million of the contingent receipt will be presented in cash flows from financing activities with the remainder, as well as all subsequent contingent receipts, presented in cash flows from operating activities. Contingent Utica Consideration Year Threshold (1) Period Cash Flow Occurs Statement of Cash Flows Presentation Contingent Receipt - Annual Remaining Contingent Payments - Aggregate Limit Divestiture Date Fair Value (In thousands) $6,145 Actual Settlement 2018 $50.00 1Q19 Financing $5,000 Remaining Potential Settlements 2019 53.00 1Q20 (2) 5,000 $10,000 2020 56.00 1Q21 (2) 5,000 (1) The price used to determine whether the specified threshold for each year has been met is the average daily closing spot price per barrel of WTI crude oil as measured by the U.S. EIA. (2) If the commodity price threshold is reached, $1.1 million of the next contingent receipt will be presented in cash flows from financing activities with the remainder, as well as all subsequent contingent receipts, presented in cash flows from operating activities. Derivative Assets and Liabilities The derivative instrument asset and liability fair values recorded in the consolidated balance sheets as of June 30, 2019 and December 31, 2018 are summarized below: June 30, 2019 Gross Amounts Recognized Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts Presented in the Consolidated Balance Sheets (In thousands) Commodity derivative instruments $21,704 ($15,582 ) $6,122 Contingent Niobrara Consideration 3,409 — 3,409 Contingent Marcellus Consideration 3 — 3 Contingent Utica Consideration 4,087 — 4,087 Derivative assets $29,203 ($15,582 ) $13,621 Commodity derivative instruments 10,303 (8,243 ) 2,060 Contingent Niobrara Consideration 1,538 — 1,538 Contingent Marcellus Consideration 447 — 447 Contingent Utica Consideration 1,970 — 1,970 Other long-term assets $14,258 ($8,243 ) $6,015 Commodity derivative instruments ($26,390 ) $8,024 ($18,366 ) Deferred premium obligations (7,558 ) 7,558 — Contingent ExL Consideration (46,385 ) — (46,385 ) Derivative liabilities-current ($80,333 ) $15,582 ($64,751 ) Commodity derivative instruments (10,988 ) 6,474 (4,514 ) Deferred premium obligations (1,769 ) 1,769 — Contingent ExL Consideration (14,413 ) — (14,413 ) Other long-term liabilities ($27,170 ) $8,243 ($18,927 ) December 31, 2018 Gross Amounts Recognized Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts Presented in the Consolidated Balance Sheets (In thousands) Commodity derivative instruments $50,406 ($20,502 ) $29,904 Contingent Niobrara Consideration 5,000 — 5,000 Contingent Utica Consideration 5,000 — 5,000 Derivative assets $60,406 ($20,502 ) $39,904 Commodity derivative instruments 6,083 (4,236 ) 1,847 Contingent Niobrara Consideration 2,035 — 2,035 Contingent Marcellus Consideration 1,369 — 1,369 Contingent Utica Consideration 2,501 — 2,501 Other long-term assets $11,988 ($4,236 ) $7,752 Commodity derivative instruments ($15,345 ) $10,140 ($5,205 ) Deferred premium obligations (10,362 ) 10,362 — Contingent ExL Consideration (50,000 ) — (50,000 ) Derivative liabilities-current ($75,707 ) $20,502 ($55,205 ) Commodity derivative instruments (10,751 ) 518 (10,233 ) Deferred premium obligations (3,718 ) 3,718 — Contingent ExL Consideration (30,584 ) — (30,584 ) Other long-term liabilities ($45,053 ) $4,236 ($40,817 ) See “Note 14. Fair Value Measurements” for additional information regarding the fair value of the Company’s derivative instruments. (Gain) loss on derivatives, net The components of “(Gain) loss on derivatives, net” in the consolidated statements of income for the three and six months ended June 30, 2019 and 2018 are summarized below: Three Months Ended June 30, Six Months Ended 2019 2018 2019 2018 (In thousands) (Gain) loss on derivatives, net Crude oil ($20,915 ) $53,437 $41,846 $82,948 NGL — 6,564 (6 ) 4,799 Natural gas (1,600 ) 153 (3,670 ) (2,892 ) Contingent ExL Consideration 1,215 10,600 30,214 16,430 Contingent Niobrara Consideration 265 (1,705 ) (2,912 ) (2,090 ) Contingent Marcellus Consideration 438 205 919 675 Contingent Utica Consideration 148 (1,540 ) (3,556 ) (2,560 ) (Gain) loss on derivatives, net ($20,449 ) $67,714 $62,835 $97,310 Cash received (paid) for derivative settlements, net There were no settlements of contingent consideration arrangements for the three months ended June 30, 2019. For the six months ended June 30, 2019 , the Company paid $50.0 million from the first annual settlement of the Contingent ExL Consideration and received $10.0 million from the first annual settlements of the Contingent Niobrara Consideration and the Contingent Utica Consideration as the specified pricing thresholds for fiscal year 2018 for each contingent consideration arrangement were exceeded. The cash paid and received for those contingent consideration settlements are classified as cash flows from financing activities as each of the settlements were less than their respective acquisition or divestiture date fair values. For the three and six months ended June 30, 2018 , there were no settlements of contingent consideration arrangements. The components of “Cash paid for derivative settlements, net” and “Cash paid for settlements of contingent consideration arrangements, net” in the consolidated statements of cash flows for the three and six months ended June 30, 2019 and 2018 are summarized below: Three Months Ended June 30, Six Months Ended 2019 2018 2019 2018 Cash Flows From Operating Activities (In thousands) Cash received (paid) for commodity derivative settlements, net Crude oil ($3,698 ) ($21,210 ) ($4,018 ) ($33,333 ) NGL — (756 ) 623 (1,188 ) Natural gas 1,925 488 1,625 540 Deferred premium obligations (2,749 ) (2,605 ) (5,390 ) (4,467 ) Cash paid for commodity derivative settlements, net ($4,522 ) ($24,083 ) ($7,160 ) ($38,448 ) Cash Flows From Financing Activities Cash received (paid) for settlements of contingent consideration arrangements, net Contingent ExL Consideration $— $— ($50,000 ) $— Contingent Niobrara Consideration — — 5,000 — Contingent Utica Consideration — — 5,000 — Cash paid for settlements of contingent consideration arrangements, net $— $— ($40,000 ) $—

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	14. Fair Value Measurements Accounting guidelines for measuring fair value establish a three-level valuation hierarchy for disclosure of fair value measurements. The valuation hierarchy categorizes assets and liabilities measured at fair value into one of three different levels depending on the observability of the inputs employed in the measurement. The three levels are defined as follows: Level 1 – Observable inputs such as quoted prices in active markets at the measurement date for identical, unrestricted assets or liabilities. Level 2 – Other inputs that are observable directly or indirectly such as quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability. Level 3 – Unobservable inputs for which there is little or no market data and which the Company makes its own assumptions about how market participants would price the assets and liabilities. Assets and Liabilities Measured at Fair Value on a Recurring Basis The following tables summarize the Company’s derivative instrument assets and liabilities measured at fair value on a recurring basis as of June 30, 2019 and December 31, 2018 : June 30, 2019 Level 1 Level 2 Level 3 (In thousands) Assets Commodity derivative instruments $— $8,182 $— Contingent Niobrara Consideration — 4,947 — Contingent Marcellus Consideration — 450 — Contingent Utica Consideration — 6,057 — Liabilities Commodity derivative instruments $— ($22,880 ) $— Contingent ExL Consideration — (60,798 ) — December 31, 2018 Level 1 Level 2 Level 3 (In thousands) Assets Commodity derivative instruments $— $31,751 $— Contingent Niobrara Consideration — 7,035 — Contingent Marcellus Consideration — 1,369 — Contingent Utica Consideration — 7,501 — Liabilities Commodity derivative instruments $— ($15,438 ) $— Contingent ExL Consideration — (80,584 ) — The asset and liability fair values reported in the consolidated balance sheets are as of the balance sheet date and subsequently change as a result of changes in commodity prices, market conditions and other factors. Commodity derivative instruments. The fair value of the Company’s commodity derivative instruments is based on a third-party industry-standard pricing model which uses contract terms and prices and assumptions and inputs that are substantially observable in active markets throughout the full term of the instruments including forward oil and gas price curves, discount rates and volatility factors, and are therefore designated as Level 2 within the valuation hierarchy. The fair values are also compared to the values provided by the counterparties for reasonableness and are adjusted for the counterparties’ credit quality for commodity derivative assets and the Company’s credit quality for commodity derivative liabilities. Contingent consideration arrangements. The fair values of the contingent consideration arrangements were determined by a third-party valuation specialist using Monte Carlo simulations including significant inputs such as forward oil and gas price curves, volatility factors, and risk adjusted discount rates, which include adjustments for the counterparties’ credit quality for contingent consideration assets and the Company’s credit quality for the contingent consideration liability. These inputs are substantially observable in active markets throughout the full term of the contingent consideration arrangements or can be derived from observable data and are therefore designated as Level 2 within the valuation hierarchy. The Company reviewed the valuations, including the related inputs, and analyzed changes in fair value measurements between periods. See “Note 13. Derivative Instruments” for additional information regarding the contingent consideration arrangements. The Company had no transfers into Level 1 and no transfers into or out of Level 2 for the six months ended June 30, 2019 . Assets and Liabilities Measured at Fair Value on a Non-Recurring Basis The fair value measurements of assets acquired and liabilities assumed, other than contingent consideration which is discussed above, are measured as of the acquisition date by a third-party valuation specialist using a discounted cash flow model based on inputs that are not observable in the market and are therefore designated as Level 3 inputs. Significant inputs to the valuation of acquired oil and gas properties include forward oil and gas price curves, estimated volumes of oil and gas reserves, expectations for timing and amount of future development and operating costs, future plugging and abandonment costs, and a risk adjusted discount rate. See “Note 4. Acquisitions and Divestitures of Oil and Gas Properties” for additional discussion. The fair value measurements of asset retirement obligations are measured as of the date a well is drilled or when production equipment and facilities are installed using a discounted cash flow model based on inputs that are not observable in the market and therefore are designated as Level 3 within the valuation hierarchy. Significant inputs to the fair value measurement of asset retirement obligations include estimates of the costs of plugging and abandoning oil and gas wells, removing production equipment and facilities and restoring the surface of the land as well as estimates of the economic lives of the oil and gas wells and future inflation rates. The fair value measurements of the Preferred Stock are measured as of the issuance date by a third-party valuation specialist using a discounted cash flow model based on inputs that are not observable in the market and therefore are designated as Level 3 inputs. Significant inputs to the valuation of the Preferred Stock include the per share cash purchase price, redemption premiums, liquidation preference, and redemption assumptions provided by the Company. Fair Value of Other Financial Instruments The Company’s other financial instruments consist of cash and cash equivalents, receivables, payables, and long-term debt. The carrying amounts of cash and cash equivalents, receivables, and payables approximate fair value due to the highly liquid or short-term nature of these instruments. The carrying amount of long-term debt associated with borrowings outstanding under the Company’s revolving credit facility approximates fair value as borrowings bear interest at variable rates. The following table presents the principal amounts of the Company’s senior notes and other long-term debt with the fair values measured using quoted secondary market trading prices which are designated as Level 1 within the valuation hierarchy. See “Note 8. Long-Term Debt” for additional discussion. June 30, 2019 December 31, 2018 Principal Amount Fair Value Principal Amount Fair Value (In thousands) 6.25% Senior Notes due 2023 $650,000 $626,438 $650,000 $599,625 8.25% Senior Notes due 2025 250,000 244,063 250,000 244,375

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	6 Months Ended
	Jun. 30, 2019
Supplemental Cash Flow Elements [Abstract]
Cash Flow, Supplemental Disclosures	15. Supplemental Cash Flow Information Supplemental cash flow disclosures and non-cash investing and financing activities are presented below: Six Months Ended 2019 2018 (In thousands) Operating activities: Cash paid for interest, net of amounts capitalized $34,475 $29,853 Cash paid for income taxes 590 — Investing activities: Increase (decrease) in capital expenditure payables and accruals $28,428 $35,543 Supplemental non-cash investing activities: Fair value of contingent consideration assets on date of divestiture $— ($7,880 ) Stock-based compensation expense capitalized to oil and gas properties 3,417 4,416 Asset retirement obligations capitalized to oil and gas properties 3,324 691 Supplemental non-cash financing activities: Non-cash loss on extinguishment of debt, net $— $2,666

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	16. Subsequent Events On July 14, 2019, the Company entered into the Merger Agreement with Callon. See “Note 1. Nature of Operations” for further discussion.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policy)	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Subsequent Events, Policy [Policy Text Block]	Subsequent Events The Company evaluates subsequent events through the date the financial statements are issued. See “Note 16. Subsequent Events” for further discussion.
New Accounting Pronouncements	Recently Adopted Accounting Standards Leases. Effective January 1, 2019, the Company adopted ASU No. 2016-02, Leases (Topic 842) (“ASC 842”), using the modified retrospective approach and did not have a cumulative-effect adjustment in retained earnings as a result of the adoption. ASC 842 significantly changes accounting for leases by requiring that lessees recognize a liability representing the obligation to make lease payments and a related right-of-use (“ROU”) asset for virtually all lease transactions. However, ASC 842 does not apply to leases of mineral rights to explore for or use crude oil and natural gas. Upon adoption, the Company implemented policy elections and practical expedients which include the following: • package of practical expedients which allows the Company to avoid reassessing contracts that commenced prior to adoption that were properly evaluated under legacy lease accounting guidance; • excluding ROU assets and lease liabilities for leases with terms that are less than one year; • combining lease and non-lease components and accounting for them as a single lease (elected by asset class); • excluding land easements that existed or expired prior to adoption; and • policy election that eliminates the need for adjusting prior period comparable financial statements prepared under legacy lease accounting guidance. As a result of adopting ASC 842, the Company recorded lease liabilities of approximately $75.2 million and associated ROU assets of approximately $69.1 million on its consolidated balance sheets. The difference between the lease liabilities and ROU assets is due to a rent holiday and lease build-out incentives that were recorded as deferred lease liabilities under legacy lease accounting guidance. The adoption of ASC 842 did not materially change the Company’s consolidated statements of income or consolidated statements of cash flows. See “Note 6. Leases” for further discussion.

Acquisitions and Divestitures (

Acquisitions and Divestitures (Tables)	6 Months Ended
	Jun. 30, 2019
Business Acquisition [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following table presents the preliminary allocation of the purchase price to the assets acquired and liabilities assumed as of the acquisition date. Preliminary Purchase Price Allocation (In thousands) Assets Other current assets $216 Oil and gas properties Proved properties 47,118 Unproved properties 150,253 Total oil and gas properties $197,371 Total assets acquired $197,587 Liabilities Revenues and royalties payable $786 Asset retirement obligations 170 Total liabilities assumed $956 Net Assets Acquired $196,631
Revenue of Acquiree since Acquisition Date, Actual	The results of operations for the Devon Acquisition have been included in the Company’s consolidated statements of income since the October 17, 2018 closing date, including total revenues and net income attributable to common shareholders for the three and six months ended June 30, 2019 as shown in the table below: Three Months Ended Six Months Ended (In thousands) Total revenues $4,342 $8,718 Net Income Attributable to Common Shareholders $2,020 $4,716

Property And Equipment, Net (Ta

Property And Equipment, Net (Tables)	6 Months Ended
	Jun. 30, 2019
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	As of June 30, 2019 and December 31, 2018 , total property and equipment, net consisted of the following: June 30, December 31, (In thousands) Oil and gas properties, full cost method Proved properties $6,685,543 $6,278,321 Accumulated depreciation, depletion and amortization and impairments (4,098,202 ) (3,944,851 ) Proved properties, net 2,587,341 2,333,470 Unproved properties, not being amortized Unevaluated leasehold and seismic costs 580,369 608,830 Capitalized interest 76,607 65,003 Total unproved properties, not being amortized 656,976 673,833 Other property and equipment 30,580 29,191 Accumulated depreciation (19,392 ) (17,970 ) Other property and equipment, net 11,188 11,221 Total property and equipment, net $3,255,505 $3,018,524

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Lease, Cost	The table below presents the components of the Company’s lease costs for the three and six months ended June 30, 2019 . Three Months Ended June 30, 2019 Six Months Ended June 30, 2019 (In thousands) Components of Lease Costs Finance lease costs Amortization of right-of-use assets (1) $410 $784 Interest on lease liabilities (2) 131 276 Operating lease costs (3) 8,700 22,780 Short-term lease costs (4) 245 463 Variable lease costs (5) 50 152 Total lease costs $9,536 $24,455
Assets and Liabilities, Lessee	The table below presents supplemental balance sheet information for the Company’s leases as of June 30, 2019 . June 30, 2019 (In thousands) Leases Operating leases: Operating lease ROU assets $64,615 Current operating lease liabilities $34,049 Long-term operating lease liabilities 36,526 Total operating lease liabilities $70,575 Financing leases: Other property and equipment, at cost $7,810 Accumulated depreciation (5,170 ) Other property and equipment, net $2,640 Current financing lease liabilities (1) $1,918 Long-term financing lease liabilities (2) 1,034 Total financing lease liabilities $2,952
Cash Flow Information, Lessee	The table below presents supplemental cash flow information for the Company’s leases for the six months ended June 30, 2019 . Six Months Ended June 30, 2019 (In thousands) Supplemental Cash Flow Information Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $5,338 Investing cash flows from operating leases $22,896 Operating cash flows from financing leases $276 Financing cash flows from financing leases $879 ROU assets obtained in exchange for lease liabilities Operating leases $9,404 Financing leases $1,082
Lease Terms and Discount Rates	The table below presents the weighted average remaining lease terms and weighted average discount rates for the Company’s leases as of June 30, 2019 . June 30, 2019 Weighted Average Remaining Lease Term (In years) Operating leases 5.1 years Financing leases 2.3 years Weighted Average Discount Rate Operating leases 8.0 % Financing leases 12.9 %
Lessee, Operating Lease, Liability, Maturity	The table below presents the maturity of the Company’s lease liabilities as of June 30, 2019 . Operating Leases Financing Leases (In thousands) July - December 2019 $20,842 $1,113 2020 27,856 1,475 2021 7,726 275 2022 3,697 234 2023 3,680 232 2024 and Thereafter 21,608 39 Total lease payments 85,409 3,368 Less: Imputed interest (14,834 ) (416 ) Total lease liabilities $70,575 $2,952

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Schedule Of Effective Income Tax Rate Reconciliation	The Company’s income tax (expense) benefit differed from the income tax (expense) benefit computed by applying the U.S. federal statutory corporate income tax rate of 21% for the three and six months ended June 30, 2019 and 2018 , to income before income taxes as follows: Three Months Ended June 30, Six Months Ended 2019 2018 2019 2018 (In thousands) Income before income taxes $109,784 $35,792 $81,752 $63,603 Income tax expense at the U.S. federal statutory rate (23,055 ) (7,517 ) (17,168 ) (13,357 ) State income tax expense, net of U.S. federal income tax benefit (874 ) (487 ) (626 ) (806 ) Tax deficiencies related to stock-based compensation (176 ) (16 ) (2,114 ) (2,542 ) (Recapture) release of valuation allowance (1,423 ) — 177,723 — Decrease in valuation allowance due to current period activity 23,211 8,048 19,273 16,449 Other 18 (511 ) 8 (546 ) Income tax (expense) benefit ($2,299 ) ($483 ) $177,096 ($802 )

Long-Term Debt (Tables)

Long-Term Debt (Tables)	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	Long-term debt consisted of the following as of June 30, 2019 and December 31, 2018 : June 30, December 31, (In thousands) Senior Secured Revolving Credit Facility due 2022 $841,328 $744,431 6.25% Senior Notes due 2023 650,000 650,000 Unamortized debt issuance costs for 6.25% Senior Notes (6,180 ) (6,878 ) 8.25% Senior Notes due 2025 250,000 250,000 Unamortized debt issuance costs for 8.25% Senior Notes (3,730 ) (3,962 ) Long-term debt $1,731,418 $1,633,591
Interest and Commitment Fee Rates	Borrowings outstanding under the credit agreement bear interest at the Company’s option at either (i) a base rate for a base rate loan plus the margin set forth in the table below, where the base rate is defined as the greatest of the prime rate, the federal funds rate plus 0.50% and the adjusted LIBO rate plus 1.00% , or (ii) an adjusted LIBO rate for a Eurodollar loan plus the margin set forth in the table below. The Company also incurs commitment fees at rates as set forth in the table below on the unused portion of lender commitments, which are included in “Interest expense, net” in the consolidated statements of income. Ratio of Outstanding Borrowings to Lender Commitments Applicable Margin for Base Rate Loans Applicable Margin for Eurodollar Loans Commitment Fee Less than 25% 0.25% 1.25% 0.375% Greater than or equal to 25% but less than 50% 0.50% 1.50% 0.375% Greater than or equal to 50% but less than 75% 0.75% 1.75% 0.500% Greater than or equal to 75% but less than 90% 1.00% 2.00% 0.500% Greater than or equal to 90% 1.25% 2.25% 0.500%

Preferred Stock (Tables)

Preferred Stock (Tables)	6 Months Ended
	Jun. 30, 2019
Preferred Stock Disclosure [Abstract]
Schedule of Preferred Stock Dividends Paid in Common Stock	The Company may elect to pay a portion of the Preferred Stock dividends in shares of its common stock in decreasing percentages as follows with respect to any preferred stock dividend declared by the Company’s Board of Directors and paid in respect of a quarter ending: Period Percentage On or after December 15, 2018 and on or prior to September 15, 2019 75 % On or after December 15, 2019 and on or prior to September 15, 2020 50 %
Temporary Equity	The table below sets forth a reconciliation of changes in the carrying amount of Preferred Stock for the six months ended June 30, 2019 and 2018 . Six Months Ended June 30, 2019 2018 (In thousands) Preferred Stock, beginning of period $174,422 $214,262 Redemption of Preferred Stock — (42,897 ) Accretion on Preferred Stock 1,634 1,493 Preferred Stock, end of period $176,056 $172,858

Shareholders' Equity and Stoc_2

Shareholders' Equity and Stock Incentive Plans (Tables)	6 Months Ended
	Jun. 30, 2019
Shareholders' Equity and Stock Incentive Plans [Abstract]
Schedule of Restricted Stock Awards and Restricted Stock Units Activity	The table below summarizes restricted stock award and unit activity for the three and six months ended June 30, 2019 and 2018 : Three Months Ended June 30, 2019 2018 Restricted Stock Awards and Units Weighted Average Grant Date Fair Value Restricted Stock Awards and Units Weighted Average Grant Date Unvested, beginning of period 3,320,060 $14.16 2,263,830 $19.15 Granted 115,936 $11.90 1,250 $15.43 Vested (52,639 ) $25.20 (43,992 ) $25.76 Forfeited (47,464 ) $12.05 (9,915 ) $18.04 Unvested, end of period 3,335,893 $13.94 2,211,173 $19.02 Six Months Ended June 30, 2019 2018 Restricted Stock Awards and Units Weighted Average Grant Date Fair Value Restricted Stock Awards and Units Weighted Average Grant Date Unvested, beginning of period 2,266,667 $19.28 1,482,655 $28.07 Granted 2,034,619 $11.06 1,348,415 $14.68 Vested (904,973 ) $20.91 (608,904 ) $31.43 Forfeited (60,420 ) $13.14 (10,993 ) $19.17 Unvested, end of period 3,335,893 $13.94 2,211,173 $19.02
Schedule of Stock Appreciation Rights Award Activity	The table below summarizes the activity for Cash SARs for the six months ended June 30, 2019 and 2018 : Six Months Ended June 30, 2019 2018 Cash SARs Weighted Average Exercise Prices Weighted Average Remaining Life (In years) Cash SARs Weighted Weighted Average Remaining Life Outstanding, beginning of period 1,330,924 $21.35 714,238 $27.12 Granted 770,775 $10.98 616,686 $14.67 Exercised — $— — $— Forfeited — $— — $— Expired — $— — $— Outstanding, end of period 2,101,699 $17.55 4.9 1,330,924 $21.35 4.8 Vested, end of period 919,800 $24.34 543,018 $27.18 Vested and exercisable, end of period — $24.34 3.0 543,018 $27.18 3.0
Schedule of Stock Appreciation Rights Valuation Assumptions	The following table summarizes the assumptions used and the resulting grant date fair value of the Cash SARs granted during the six months ended June 30, 2019 and 2018 : Six Months Ended June 30, 2019 2018 Expected term (in years) 6.1 6.0 Expected volatility 56.0 % 54.3 % Risk-free interest rate 2.6 % 2.8 % Dividend yield — % — % Grant date fair value per Cash SAR $6.00 $7.89
Schedule of Performance Shares Award Unvested Activity	The table below summarizes performance share activity for the six months ended June 30, 2019 and 2018 : Six Months Ended June 30, 2019 2018 Target Performance Shares (1) Weighted Average Grant Date Fair Value Target Performance Shares (1) Weighted Average Grant Date Unvested, beginning of period 182,209 $27.01 144,955 $47.14 Granted 130,302 $14.20 93,771 $19.09 Vested at end of performance period (31,244 ) $35.71 (49,458 ) $65.51 Did not vest at end of performance period (10,407 ) $35.71 (7,059 ) $65.51 Forfeited — $— — $— Unvested, end of period 270,860 $19.51 182,209 $27.01
Results of Total Shareholder Return Ranking	The following table presents the results of the Company’s final TSR ranking during the performance periods that ended during the six months ended June 30, 2019 and 2018 : Six Months Ended June 30, 2019 2018 Target performance shares granted 41,651 56,517 Multiplier 75 % 88 % Performance shares vested 31,244 49,458 Performance shares that did not vest 10,407 7,059 Aggregate fair value of performance shares vested (In millions) $0.4 $0.8
Schedule of Performance Share Award Valuation Assumptions	following table summarizes the assumptions used and the resulting grant date fair value per performance share for the grant activity during the six months ended June 30, 2019 : Six Months Ended June 30, 2019 2018 Number of simulations 500,000 500,000 Expected term (in years) 3.1 3.0 Expected volatility 58.2 % 61.5 % Risk-free interest rate 2.5 % 2.4 % Dividend yield — % — % Grant date fair value per performance share $14.20 $19.09
Schedule of Stock-based Compensation, net	The Company recognized the following stock-based compensation expense, net for the three and six months ended June 30, 2019 and 2018 : Three Months Ended June 30, Six Months Ended 2019 2018 2019 2018 (In thousands) Restricted stock awards and units $5,358 $4,720 $10,181 $9,804 Cash SARs (426 ) 5,788 334 4,373 Performance shares 436 406 871 963 5,368 10,914 11,386 15,140 Less: amounts capitalized to oil and gas properties (1,514 ) (3,708 ) (3,417 ) (4,416 ) Total stock-based compensation expense, net $3,854 $7,206 $7,969 $10,724

Earnings per Share (Tables)

Earnings per Share (Tables)	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Schedule of Supplemental Net Income Per Common Share	The following table summarizes the calculation of net income attributable to common shareholders per common share: Three Months Ended June 30, Six Months Ended 2019 2018 2019 2018 (In thousands, except per share amounts) Net Income $107,485 $35,309 $258,848 $62,801 Dividends on preferred stock (4,452 ) (4,474 ) (8,812 ) (9,337 ) Accretion on preferred stock (833 ) (740 ) (1,634 ) (1,493 ) Loss on redemption of preferred stock — — — (7,133 ) Net Income Attributable to Common Shareholders $102,200 $30,095 $248,402 $44,838 Basic weighted average common shares outstanding 92,497 82,058 92,121 81,802 Dilutive effect of restricted stock and performance shares 203 967 358 798 Dilutive effect of common stock warrants — 828 — 640 Diluted weighted average common shares outstanding 92,700 83,853 92,479 83,240 Net Income Attributable to Common Shareholders Per Common Share Basic $1.10 $0.37 $2.70 $0.55 Diluted $1.10 $0.36 $2.69 $0.54
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	The following table presents the weighted average anti-dilutive securities for the periods presented: Three Months Ended June 30, Six Months Ended 2019 2018 2019 2018 (In thousands) Anti-dilutive restricted stock and performance shares 3,077 16 1,526 19 Anti-dilutive common stock warrants 2,750 — 2,750 — Total weighted average anti-dilutive securities 5,827 16 4,276 19

Derivative Instruments (Tables)

Derivative Instruments (Tables)	6 Months Ended
	Jun. 30, 2019
Derivative [Line Items]
Schedule of Contingent Consideration	The purchase and sale agreements for the acquisition of properties in the Delaware Basin from ExL Petroleum Management, LLC and ExL Petroleum Operating Inc. (the “ExL Acquisition”) in 2017 and divestitures of the Company’s assets in the Niobrara in 2018, and Marcellus and Utica in 2017, included contingent consideration arrangements that require the Company to pay or entitle the Company to receive specified amounts if commodity prices exceed specified thresholds, which are summarized in the tables below. If the pricing threshold for the respective contingent consideration arrangement is met, the payment is made or received in the first quarter of the following year. See “Note 3. Acquisitions and Divestitures of Oil and Gas Properties” of the Notes to Consolidated Financial Statements in the 2018 Annual Report for further discussion of these transactions. See “—Cash received (paid) for settlements of contingent consideration arrangements, net” below for discussion of the settlements that occurred during the first quarter of 2019. Contingent ExL Consideration Year Threshold (1) Period Cash Flow Occurs Statement of Cash Flows Presentation Contingent Payment - Annual Remaining Contingent Payments - Aggregate Limit Acquisition Date Fair Value (In thousands) ($52,300 ) Actual Settlement 2018 $50.00 1Q19 Financing ($50,000 ) Remaining Potential Settlements 2019-2021 50.00 (2) (2) (50,000 ) ($75,000 ) (1) The price used to determine whether the specified threshold for each year has been met is the average daily closing spot price per barrel of WTI crude oil as measured by the U.S. Energy Information Administration (“U.S. EIA”). (2) Cash paid for settlements of contingent consideration arrangements are classified as cash flows from financing activities up to the acquisition date fair value with any excess classified as cash flows from operating activities. Therefore, if the commodity price threshold is reached, $2.3 million of the next contingent payment will be presented in cash flows from financing activities with the remainder, as well as all subsequent contingent payments, presented in cash flows from operating activities. Contingent Niobrara Consideration Year Threshold (1) Period Cash Flow Occurs Statement of Cash Flows Presentation Contingent Receipt - Annual Remaining Contingent Payments - Aggregate Limit Divestiture Date Fair Value (In thousands) $7,880 Actual Settlement 2018 $55.00 1Q19 Financing $5,000 Remaining Potential Settlements 2019 55.00 1Q20 (2) 5,000 $10,000 2020 60.00 1Q21 (2) 5,000 (1) The price used to determine whether the specified threshold for each year has been met is the average daily closing spot price per barrel of WTI crude oil as measured by the U.S. EIA. (2) If the commodity price threshold is reached, $2.9 million of the next contingent receipt will be presented in cash flows from financing activities with the remainder, as well as all subsequent contingent receipts, presented in cash flows from operating activities. Contingent Marcellus Consideration Year Threshold (1) Period Cash Flow Occurs Statement of Cash Flows Presentation Contingent Receipt - Annual Remaining Contingent Payments - Aggregate Limit Divestiture Date Fair Value (In thousands) $2,660 Actual Settlement 2018 $3.13 1Q19 N/A $— Remaining Potential Settlements 2019 3.18 1Q20 (2) 3,000 $6,000 2020 3.30 1Q21 (2) 3,000 (1) The price used to determine whether the specified threshold for each year has been met is the average monthly settlement price per MMBtu of Henry Hub natural gas for the next calendar month, as determined on the last business day preceding each calendar month as measured by the CME Group Inc. (2) For the first quarter of 2019 , there was no settlement for the Contingent Marcellus Consideration. Therefore, if the commodity price threshold is reached, $2.7 million of the contingent receipt will be presented in cash flows from financing activities with the remainder, as well as all subsequent contingent receipts, presented in cash flows from operating activities. Contingent Utica Consideration Year Threshold (1) Period Cash Flow Occurs Statement of Cash Flows Presentation Contingent Receipt - Annual Remaining Contingent Payments - Aggregate Limit Divestiture Date Fair Value (In thousands) $6,145 Actual Settlement 2018 $50.00 1Q19 Financing $5,000 Remaining Potential Settlements 2019 53.00 1Q20 (2) 5,000 $10,000 2020 56.00 1Q21 (2) 5,000 (1) The price used to determine whether the specified threshold for each year has been met is the average daily closing spot price per barrel of WTI crude oil as measured by the U.S. EIA. (2) If the commodity price threshold is reached, $1.1 million of the next contingent receipt will be presented in cash flows from financing activities with the remainder, as well as all subsequent contingent receipts, presented in cash flows from operating activities.
Schedule of Derivative Instrument Fair Value Assets and Liabilities	The derivative instrument asset and liability fair values recorded in the consolidated balance sheets as of June 30, 2019 and December 31, 2018 are summarized below: June 30, 2019 Gross Amounts Recognized Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts Presented in the Consolidated Balance Sheets (In thousands) Commodity derivative instruments $21,704 ($15,582 ) $6,122 Contingent Niobrara Consideration 3,409 — 3,409 Contingent Marcellus Consideration 3 — 3 Contingent Utica Consideration 4,087 — 4,087 Derivative assets $29,203 ($15,582 ) $13,621 Commodity derivative instruments 10,303 (8,243 ) 2,060 Contingent Niobrara Consideration 1,538 — 1,538 Contingent Marcellus Consideration 447 — 447 Contingent Utica Consideration 1,970 — 1,970 Other long-term assets $14,258 ($8,243 ) $6,015 Commodity derivative instruments ($26,390 ) $8,024 ($18,366 ) Deferred premium obligations (7,558 ) 7,558 — Contingent ExL Consideration (46,385 ) — (46,385 ) Derivative liabilities-current ($80,333 ) $15,582 ($64,751 ) Commodity derivative instruments (10,988 ) 6,474 (4,514 ) Deferred premium obligations (1,769 ) 1,769 — Contingent ExL Consideration (14,413 ) — (14,413 ) Other long-term liabilities ($27,170 ) $8,243 ($18,927 ) December 31, 2018 Gross Amounts Recognized Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts Presented in the Consolidated Balance Sheets (In thousands) Commodity derivative instruments $50,406 ($20,502 ) $29,904 Contingent Niobrara Consideration 5,000 — 5,000 Contingent Utica Consideration 5,000 — 5,000 Derivative assets $60,406 ($20,502 ) $39,904 Commodity derivative instruments 6,083 (4,236 ) 1,847 Contingent Niobrara Consideration 2,035 — 2,035 Contingent Marcellus Consideration 1,369 — 1,369 Contingent Utica Consideration 2,501 — 2,501 Other long-term assets $11,988 ($4,236 ) $7,752 Commodity derivative instruments ($15,345 ) $10,140 ($5,205 ) Deferred premium obligations (10,362 ) 10,362 — Contingent ExL Consideration (50,000 ) — (50,000 ) Derivative liabilities-current ($75,707 ) $20,502 ($55,205 ) Commodity derivative instruments (10,751 ) 518 (10,233 ) Deferred premium obligations (3,718 ) 3,718 — Contingent ExL Consideration (30,584 ) — (30,584 ) Other long-term liabilities ($45,053 ) $4,236 ($40,817 )
Schedule of (Gain) Loss on Derivative Instruments	The components of “(Gain) loss on derivatives, net” in the consolidated statements of income for the three and six months ended June 30, 2019 and 2018 are summarized below: Three Months Ended June 30, Six Months Ended 2019 2018 2019 2018 (In thousands) (Gain) loss on derivatives, net Crude oil ($20,915 ) $53,437 $41,846 $82,948 NGL — 6,564 (6 ) 4,799 Natural gas (1,600 ) 153 (3,670 ) (2,892 ) Contingent ExL Consideration 1,215 10,600 30,214 16,430 Contingent Niobrara Consideration 265 (1,705 ) (2,912 ) (2,090 ) Contingent Marcellus Consideration 438 205 919 675 Contingent Utica Consideration 148 (1,540 ) (3,556 ) (2,560 ) (Gain) loss on derivatives, net ($20,449 ) $67,714 $62,835 $97,310
Schedule of Cash Received for Derivatives	The components of “Cash paid for derivative settlements, net” and “Cash paid for settlements of contingent consideration arrangements, net” in the consolidated statements of cash flows for the three and six months ended June 30, 2019 and 2018 are summarized below: Three Months Ended June 30, Six Months Ended 2019 2018 2019 2018 Cash Flows From Operating Activities (In thousands) Cash received (paid) for commodity derivative settlements, net Crude oil ($3,698 ) ($21,210 ) ($4,018 ) ($33,333 ) NGL — (756 ) 623 (1,188 ) Natural gas 1,925 488 1,625 540 Deferred premium obligations (2,749 ) (2,605 ) (5,390 ) (4,467 ) Cash paid for commodity derivative settlements, net ($4,522 ) ($24,083 ) ($7,160 ) ($38,448 ) Cash Flows From Financing Activities Cash received (paid) for settlements of contingent consideration arrangements, net Contingent ExL Consideration $— $— ($50,000 ) $— Contingent Niobrara Consideration — — 5,000 — Contingent Utica Consideration — — 5,000 — Cash paid for settlements of contingent consideration arrangements, net $— $— ($40,000 ) $—
Crude Oil
Derivative [Line Items]
Schedule of Derivative Instruments	As of June 30, 2019 , the Company had the following outstanding commodity derivative instruments at weighted average contract volumes and prices: Commodity Period Type of Contract Index Volumes (Bbls per day) Fixed Price ($ per Bbl) Sub-Floor Price ($ per Bbl) Floor Price ($ per Bbl) Ceiling Price ($ per Bbl) Fixed Price Differential ($ per Bbl) Crude oil 3Q19 Price Swaps NYMEX WTI 5,000 $64.80 — — — — Crude oil 3Q19 Three-Way Collars NYMEX WTI 27,000 — $41.67 $50.96 $74.23 — Crude oil 3Q19 Basis Swaps LLS-WTI Cushing 6,000 — — — — $5.16 Crude oil 3Q19 Basis Swaps WTI Midland-WTI Cushing 9,100 — — — — ($4.44 ) Crude oil 3Q19 Sold Call Options NYMEX WTI 3,875 — — — $81.07 — Crude oil 4Q19 Price Swaps NYMEX WTI 5,000 $64.80 — — — — Crude oil 4Q19 Three-Way Collars NYMEX WTI 27,000 — $41.67 $50.96 $74.23 — Crude oil 4Q19 Basis Swaps WTI Midland-WTI Cushing 9,200 — — — — ($4.64 ) Crude oil 4Q19 Sold Call Options NYMEX WTI 3,875 — — — $81.07 — Crude oil 2020 Price Swaps NYMEX WTI 3,000 $55.06 — — — — Crude oil 2020 Three-Way Collars NYMEX WTI 12,000 — $45.63 $55.63 $66.04 — Crude oil 2020 Basis Swaps WTI Midland-WTI Cushing 10,658 — — — — ($1.68 ) Crude oil 2020 Sold Call Options NYMEX WTI 4,575 — — — $75.98 — Crude oil 2021 Basis Swaps WTI Midland-WTI Cushing 8,000 — — — — $0.18
Natural Gas
Derivative [Line Items]
Schedule of Derivative Instruments	Commodity Period Type of Contract Index Volumes (MMBtu per day) Fixed Price ($ per MMBtu) Sub-Floor Price ($ per MMBtu) Floor Price ($ per MMBtu) Ceiling Price ($ per MMBtu) Fixed Price Differential ($ per MMBtu) Natural gas 3Q19 Basis Swaps Waha-NYMEX Henry Hub 42,500 — — — — ($1.49 ) Natural gas 3Q19 Sold Call Options NYMEX Henry Hub 33,000 — — $3.25 — Natural gas 4Q19 Basis Swaps Waha-NYMEX Henry Hub 42,500 — — — — ($1.30 ) Natural gas 4Q19 Sold Call Options NYMEX Henry Hub 33,000 — — $3.25 — Natural gas 2020 Basis Swaps Waha-NYMEX Henry Hub 29,541 — — — — ($0.77 ) Natural gas 2020 Sold Call Options NYMEX Henry Hub 33,000 — — $3.50 —
ExL Acquisition
Derivative [Line Items]
Schedule of Contingent Consideration	Contingent ExL Consideration Year Threshold (1) Period Cash Flow Occurs Statement of Cash Flows Presentation Contingent Payment - Annual Remaining Contingent Payments - Aggregate Limit Acquisition Date Fair Value (In thousands) ($52,300 ) Actual Settlement 2018 $50.00 1Q19 Financing ($50,000 ) Remaining Potential Settlements 2019-2021 50.00 (2) (2) (50,000 ) ($75,000 ) (1) The price used to determine whether the specified threshold for each year has been met is the average daily closing spot price per barrel of WTI crude oil as measured by the U.S. Energy Information Administration (“U.S. EIA”). (2) Cash paid for settlements of contingent consideration arrangements are classified as cash flows from financing activities up to the acquisition date fair value with any excess classified as cash flows from operating activities. Therefore, if the commodity price threshold is reached, $2.3 million
Niobrara Divestiture
Derivative [Line Items]
Schedule of Contingent Consideration	Contingent Niobrara Consideration Year Threshold (1) Period Cash Flow Occurs Statement of Cash Flows Presentation Contingent Receipt - Annual Remaining Contingent Payments - Aggregate Limit Divestiture Date Fair Value (In thousands) $7,880 Actual Settlement 2018 $55.00 1Q19 Financing $5,000 Remaining Potential Settlements 2019 55.00 1Q20 (2) 5,000 $10,000 2020 60.00 1Q21 (2) 5,000 (1) The price used to determine whether the specified threshold for each year has been met is the average daily closing spot price per barrel of WTI crude oil as measured by the U.S. EIA. (2) If the commodity price threshold is reached, $2.9 million of the next contingent receipt will be presented in cash flows from financing activities with the remainder, as well as all subsequent contingent receipts, presented in cash flows from operating activities.
Marcellus Shale Divestiture
Derivative [Line Items]
Schedule of Contingent Consideration	Contingent Marcellus Consideration Year Threshold (1) Period Cash Flow Occurs Statement of Cash Flows Presentation Contingent Receipt - Annual Remaining Contingent Payments - Aggregate Limit Divestiture Date Fair Value (In thousands) $2,660 Actual Settlement 2018 $3.13 1Q19 N/A $— Remaining Potential Settlements 2019 3.18 1Q20 (2) 3,000 $6,000 2020 3.30 1Q21 (2) 3,000 (1) The price used to determine whether the specified threshold for each year has been met is the average monthly settlement price per MMBtu of Henry Hub natural gas for the next calendar month, as determined on the last business day preceding each calendar month as measured by the CME Group Inc. (2) For the first quarter of 2019 , there was no settlement for the Contingent Marcellus Consideration. Therefore, if the commodity price threshold is reached, $2.7 million of the contingent receipt will be presented in cash flows from financing activities with the remainder, as well as all subsequent contingent receipts, presented in cash flows from operating activities.
Utica Shale Divestiture
Derivative [Line Items]
Schedule of Contingent Consideration	Contingent Utica Consideration Year Threshold (1) Period Cash Flow Occurs Statement of Cash Flows Presentation Contingent Receipt - Annual Remaining Contingent Payments - Aggregate Limit Divestiture Date Fair Value (In thousands) $6,145 Actual Settlement 2018 $50.00 1Q19 Financing $5,000 Remaining Potential Settlements 2019 53.00 1Q20 (2) 5,000 $10,000 2020 56.00 1Q21 (2) 5,000 (1) The price used to determine whether the specified threshold for each year has been met is the average daily closing spot price per barrel of WTI crude oil as measured by the U.S. EIA. (2) If the commodity price threshold is reached, $1.1 million of the next contingent receipt will be presented in cash flows from financing activities with the remainder, as well as all subsequent contingent receipts, presented in cash flows from operating activities.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following tables summarize the Company’s derivative instrument assets and liabilities measured at fair value on a recurring basis as of June 30, 2019 and December 31, 2018 : June 30, 2019 Level 1 Level 2 Level 3 (In thousands) Assets Commodity derivative instruments $— $8,182 $— Contingent Niobrara Consideration — 4,947 — Contingent Marcellus Consideration — 450 — Contingent Utica Consideration — 6,057 — Liabilities Commodity derivative instruments $— ($22,880 ) $— Contingent ExL Consideration — (60,798 ) — December 31, 2018 Level 1 Level 2 Level 3 (In thousands) Assets Commodity derivative instruments $— $31,751 $— Contingent Niobrara Consideration — 7,035 — Contingent Marcellus Consideration — 1,369 — Contingent Utica Consideration — 7,501 — Liabilities Commodity derivative instruments $— ($15,438 ) $— Contingent ExL Consideration — (80,584 ) —
Schedule of Carrying Value and Fair Value of Debt Instruments	The following table presents the principal amounts of the Company’s senior notes and other long-term debt with the fair values measured using quoted secondary market trading prices which are designated as Level 1 within the valuation hierarchy. See “Note 8. Long-Term Debt” for additional discussion. June 30, 2019 December 31, 2018 Principal Amount Fair Value Principal Amount Fair Value (In thousands) 6.25% Senior Notes due 2023 $650,000 $626,438 $650,000 $599,625 8.25% Senior Notes due 2025 250,000 244,063 250,000 244,375

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	6 Months Ended
	Jun. 30, 2019
Supplemental Cash Flow Elements [Abstract]
Schedule of Cash Flow, Supplemental Disclosures	Supplemental cash flow disclosures and non-cash investing and financing activities are presented below: Six Months Ended 2019 2018 (In thousands) Operating activities: Cash paid for interest, net of amounts capitalized $34,475 $29,853 Cash paid for income taxes 590 — Investing activities: Increase (decrease) in capital expenditure payables and accruals $28,428 $35,543 Supplemental non-cash investing activities: Fair value of contingent consideration assets on date of divestiture $— ($7,880 ) Stock-based compensation expense capitalized to oil and gas properties 3,417 4,416 Asset retirement obligations capitalized to oil and gas properties 3,324 691 Supplemental non-cash financing activities: Non-cash loss on extinguishment of debt, net $— $2,666

Subsequent Events (Tables)

Subsequent Events (Tables)	6 Months Ended
	Jun. 30, 2019
Crude Oil
Derivative [Line Items]
Schedule of Derivative Instruments	As of June 30, 2019 , the Company had the following outstanding commodity derivative instruments at weighted average contract volumes and prices: Commodity Period Type of Contract Index Volumes (Bbls per day) Fixed Price ($ per Bbl) Sub-Floor Price ($ per Bbl) Floor Price ($ per Bbl) Ceiling Price ($ per Bbl) Fixed Price Differential ($ per Bbl) Crude oil 3Q19 Price Swaps NYMEX WTI 5,000 $64.80 — — — — Crude oil 3Q19 Three-Way Collars NYMEX WTI 27,000 — $41.67 $50.96 $74.23 — Crude oil 3Q19 Basis Swaps LLS-WTI Cushing 6,000 — — — — $5.16 Crude oil 3Q19 Basis Swaps WTI Midland-WTI Cushing 9,100 — — — — ($4.44 ) Crude oil 3Q19 Sold Call Options NYMEX WTI 3,875 — — — $81.07 — Crude oil 4Q19 Price Swaps NYMEX WTI 5,000 $64.80 — — — — Crude oil 4Q19 Three-Way Collars NYMEX WTI 27,000 — $41.67 $50.96 $74.23 — Crude oil 4Q19 Basis Swaps WTI Midland-WTI Cushing 9,200 — — — — ($4.64 ) Crude oil 4Q19 Sold Call Options NYMEX WTI 3,875 — — — $81.07 — Crude oil 2020 Price Swaps NYMEX WTI 3,000 $55.06 — — — — Crude oil 2020 Three-Way Collars NYMEX WTI 12,000 — $45.63 $55.63 $66.04 — Crude oil 2020 Basis Swaps WTI Midland-WTI Cushing 10,658 — — — — ($1.68 ) Crude oil 2020 Sold Call Options NYMEX WTI 4,575 — — — $75.98 — Crude oil 2021 Basis Swaps WTI Midland-WTI Cushing 8,000 — — — — $0.18
Natural Gas
Derivative [Line Items]
Schedule of Derivative Instruments	Commodity Period Type of Contract Index Volumes (MMBtu per day) Fixed Price ($ per MMBtu) Sub-Floor Price ($ per MMBtu) Floor Price ($ per MMBtu) Ceiling Price ($ per MMBtu) Fixed Price Differential ($ per MMBtu) Natural gas 3Q19 Basis Swaps Waha-NYMEX Henry Hub 42,500 — — — — ($1.49 ) Natural gas 3Q19 Sold Call Options NYMEX Henry Hub 33,000 — — $3.25 — Natural gas 4Q19 Basis Swaps Waha-NYMEX Henry Hub 42,500 — — — — ($1.30 ) Natural gas 4Q19 Sold Call Options NYMEX Henry Hub 33,000 — — $3.25 — Natural gas 2020 Basis Swaps Waha-NYMEX Henry Hub 29,541 — — — — ($0.77 ) Natural gas 2020 Sold Call Options NYMEX Henry Hub 33,000 — — $3.50 —

Nature of Operations (Details)

Nature of Operations (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Dec. 31, 2019	Sep. 30, 2017	Jun. 30, 2019	Dec. 31, 2018	Aug. 10, 2017
Proposed Merger Disclosures [Line Items]
Common stock, par value (in dollars per share)				$ 0.01
Preferred Stock, Par or Stated Value Per Share			$ 0.01	$ 0.01
Carrizo [Member]
Proposed Merger Disclosures [Line Items]
Common stock, par value (in dollars per share)			$ 0.01
Preferred Stock, Dividend Rate, Percentage		8.875%
Preferred Stock, Par or Stated Value Per Share					$ 0.01
Subsequent Event [Member] | Callon [Member]
Proposed Merger Disclosures [Line Items]
Common stock, par value (in dollars per share)	$ 0.01
Merger Common Stock Conversion Rate	2.05
Preferred Stock, Dividend Rate, Percentage	8.875%
Preferred Stock, Par or Stated Value Per Share	$ 0.01
Merger Preferred Stock Conversion Rate	1
Scenario, Forecast [Member] | Carrizo [Member]
Proposed Merger Disclosures [Line Items]
Loss on Contract Termination	$ 47.4
Expense Reimbursement Upon Contract Termination	7.5
Scenario, Forecast [Member] | Callon [Member]
Proposed Merger Disclosures [Line Items]
Loss on Contract Termination	57
Expense Reimbursement Upon Contract Termination	$ 7.5

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Summary Of Significant Accounting Policies [Line Items]
Operating lease right-of-use assets	$ 64,615	$ 69,100	$ 0
Operating Lease, Liability	$ 70,575	$ 75,200

Revenue Recognition (Details)

Revenue Recognition (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Revenue Recognition [Abstract]
Receivable from Contract with Customer	$ 76.9	$ 77.1

Acquisitions and Divestitures_2

Acquisitions and Divestitures (Narrative) (Details) - USD ($) $ in Thousands

1 Months Ended

3 Months Ended

6 Months Ended

8 Months Ended

12 Months Ended

Feb. 28, 2018

Jan. 31, 2018

Mar. 31, 2019

Dec. 31, 2018

Sep. 30, 2018

Mar. 31, 2018

Dec. 31, 2017

Jun. 30, 2019

Jun. 30, 2018

Mar. 31, 2019

Jul. 31, 2018

Sep. 30, 2018

Dec. 11, 2017

Nov. 20, 2017

Business Acquisition [Line Items]

Acquisition of oil and gas properties

$ 8,222

$ 0

Proceeds from divestitures of oil and gas properties, net

$ 6,034

$ 345,789

Devon Acquisition

Business Acquisition [Line Items]

Agreed upon Purchase Price of Oil and Gas Property and Equipment

$ 215,000

Deposit For Acquisition Of Oil And Gas Properties

21,500

Payments to Acquire Oil and Gas Property

$ 183,400

Acquisition of oil and gas properties

$ (8,300)

Estimated Aggregate Purchase Price

$ 196,600

Eagle Ford Shale Divestiture

Business Acquisition [Line Items]

Sale Price of Oil and Gas Property and Equipment

$ 245,000

Proceeds from divestitures of oil and gas properties, net

$ 245,700

Cash Paid for Post-Closing Adjustments to Divestitures

(500)

Niobrara Divestiture

Business Acquisition [Line Items]

Sale Price of Oil and Gas Property and Equipment

$ 140,000

Proceeds from divestitures of oil and gas properties, net

$ 122,600

$ 14,000

$ 135,600

Cash Paid for Post-Closing Adjustments to Divestitures

$ (1,000)

Deposit Received Prior To Closing [Member] | Eagle Ford Shale Divestiture

Business Acquisition [Line Items]

Proceeds from divestitures of oil and gas properties, net

$ 24,500

Cash Received At Closing [Member] | Eagle Ford Shale Divestiture

Business Acquisition [Line Items]

Proceeds from divestitures of oil and gas properties, net

$ 211,700

Cash Received Post Closing [Member] | Eagle Ford Shale Divestiture

Business Acquisition [Line Items]

Proceeds from divestitures of oil and gas properties, net

$ 10,000

Acquisitions (Schedule of Consi

Acquisitions (Schedule of Consideration Paid for Assets Acquired and Liabilities Assumed) (Table) (Details) - Devon Acquisition $ in Thousands	Oct. 17, 2018USD ($)
Business Acquisition [Line Items]
Business Combination, Current Assets	$ 216
Business Combination, Proved Oil and Gas Properties	47,118
Business Combination, Unproved Oil and Gas Properties	150,253
Business Combination, Oil and Gas Properties	197,371
Business Combination, Assets	197,587
Business Combination, Current Liabilities	786
Business Combination, Noncurrent Liabilities	170
Business Combination, Liabilities	956
Business Combination, Assets Acquired and Liabilities Assumed, Net	$ 196,631

Acquisitions and Divestitures A

Acquisitions and Divestitures Acquisitions (Revenue and Income of Acquiree Since Acquisition Date) (Details) - Devon Acquisition - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Business Acquisition [Line Items]
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual	$ 4,342	$ 8,718
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual	$ 2,020	$ 4,716

Property and Equipment, Net (Na

Property and Equipment, Net (Narrative) (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)$ / Boe	Jun. 30, 2018USD ($)$ / Boe	Jun. 30, 2019USD ($)$ / Boe	Jun. 30, 2018USD ($)$ / Boe
Property, Plant and Equipment [Line Items]
Average depreciation, depletion and amortization, per Boe | $ / Boe	13.28	13.74	13.28	13.73
Internal costs capitalized, Oil and Gas producing activities	$ 3.8	$ 6.1	$ 12.9	$ 12.7
Capitalized interest	$ 8.6	$ 8.7	$ 17.6	$ 19.1

Property And Equipment, Net (Sc

Property And Equipment, Net (Schedule Of Property And Equipment) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Proved properties	$ 6,685,543	$ 6,278,321
Accumulated depreciation, depletion and amortization and impairments	(4,098,202)	(3,944,851)
Proved properties, net	2,587,341	2,333,470
Unproved properties, not being amortized
Unevaluated leasehold and seismic costs	580,369	608,830
Capitalized interest	76,607	65,003
Total unproved properties, not being amortized	656,976	673,833
Other property and equipment	30,580	29,191
Accumulated depreciation	(19,392)	(17,970)
Other property and equipment, net	11,188	11,221
Total property and equipment, net	$ 3,255,505	$ 3,018,524

Leases (Details)

Leases (Details)	Jun. 30, 2019
Drilling Rigs [Member] | Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	1 year
Drilling Rigs [Member] | Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	3 years
Office Building [Member] | Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	1 year
Office Building [Member] | Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	15 years
Support Equipment and Facilities [Member] | Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	1 year
Support Equipment and Facilities [Member] | Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	3 years

Leases (Schedule of Lease Cost)

Leases (Schedule of Lease Cost) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Lessee, Lease, Description [Line Items]
Finance Lease, Right-of-Use Asset, Amortization	$ 410	$ 784
Finance Lease, Interest Expense	131	276
Operating Lease, Cost	8,700	22,780
Short-term Lease, Cost	245	463
Variable Lease, Cost	50	152
Lease, Cost	9,536	24,455
Drilling Rigs [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	$ 6,100	$ 17,600

Leases (Operating and Financial

Leases (Operating and Financial Leases Financial Statement Location) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Lease Financial Statement Location [Abstract]
Operating lease right-of-use assets	$ 64,615	$ 69,100	$ 0
Operating lease liabilities	34,049		0
Operating lease liabilities	36,526		$ 0
Operating Lease, Liability	70,575	$ 75,200
Finance lease ROU asset, gross	7,810
Finance lease ROU asset, accumulated amortization	(5,170)
Finance lease right of use asset	2,640
Finance lease liability, current	1,918
Finance lease liability, noncurrent	1,034
Finance lease liability	$ 2,952

Leases (Supplemental Cash Flow

Leases (Supplemental Cash Flow Information Leases) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2019USD ($)
Leases Supplemental Cash Flow Information [Line Items]
Finance Lease, Interest Payment on Liability	$ 276
Finance Lease, Principal Payments	879
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	9,404
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	1,082
Operating Activities [Member]
Leases Supplemental Cash Flow Information [Line Items]
Operating Lease, Payments	5,338
Investing Activities [Member]
Leases Supplemental Cash Flow Information [Line Items]
Operating Lease, Payments	$ 22,896

Leases (Schedule of Lease Terms

Leases (Schedule of Lease Terms and Discount Rates) (Details)	Jun. 30, 2019
Lease Financial Statement Location [Abstract]
Operating Lease, Weighted Average Remaining Lease Term	5 years 1 month 6 days
Finance Lease, Weighted Average Remaining Lease Term	2 years 3 months 18 days
Operating Lease, Weighted Average Discount Rate, Percent	8.00%
Finance Lease, Weighted Average Discount Rate, Percent	12.90%

Leases (Schedule of Lease Liabi

Leases (Schedule of Lease Liabilities) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019
Schedule of Lease Liabilities [Abstract]
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	$ 20,842
Lessee, Operating Lease, Liability, Payments, Due Year Two	27,856
Lessee, Operating Lease, Liability, Payments, Due Year Three	7,726
Lessee, Operating Lease, Liability, Payments, Due Year Four	3,697
Lessee, Operating Lease, Liability, Payments, Due Year Five	3,680
Lessee, Operating Lease, Liability, Payments, Due after Year Five	21,608
Lessee, Operating Lease, Liability, Payments, Due	85,409
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(14,834)
Operating Lease, Liability	70,575	$ 75,200
Finance Lease, Liability, Payments, Remainder of Fiscal Year	1,113
Finance Lease, Liability, Payments, Due Year Two	1,475
Finance Lease, Liability, Payments, Due Year Three	275
Finance Lease, Liability, Payments, Due Year Four	234
Finance Lease, Liability, Payments, Due Year Five	232
Finance Lease, Liability, Payments, Due after Year Five	39
Finance Lease, Liability, Payments, Due	3,368
Finance Lease, Liability, Undiscounted Excess Amount	(416)
Finance lease liability	$ 2,952

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Income Taxes [Line Items]
U.S. federal statutory corporate pretax rate				21.00%
Deferred Tax Assets, Valuation Allowance	$ 45,900			$ 45,900		$ 242,900
Partial Release Of Valuation Allowance	$ 1,423	$ (179,100)	$ 0	$ (177,723)	$ 0

Income Taxes (Schedule Of Effec

Income Taxes (Schedule Of Effective Income Tax Rate Reconciliation) (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Income before income taxes	$ 109,784		$ 35,792	$ 81,752	$ 63,603
Income tax expense at the U.S. federal statutory rate	(23,055)		(7,517)	(17,168)	(13,357)
State income tax expense, net of U.S. federal income tax benefit	(874)		(487)	(626)	(806)
Tax deficiencies related to stock-based compensation	(176)		(16)	(2,114)	(2,542)
Partial Release Of Valuation Allowance	(1,423)	$ 179,100	0	177,723	0
Decrease in valuation allowance due to current period activity	23,211		8,048	19,273	16,449
Other	18		(511)	8	(546)
Income tax (expense) benefit	$ (2,299)		$ (483)	$ 177,096	$ (802)

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Jun. 30, 2019USD ($)Rate	Jun. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Debt Instrument [Line Items]
Cash paid for debt redemption			$ 336,900
Redemption Premium			6,000
Accrued interest paid associated with redemption of debt			10,900
Loss on extinguishment of debt	$ 0	$ 0	8,700	$ 0	$ 8,676
Write off of Deferred Debt Issuance Cost			2,700
Voting interest of the subsidiary owned by the registrant	100.00%			100.00%
Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity	$ 1,350,000			$ 1,350,000
Line of Credit Facility, Elected Borrowing Capacity	1,250,000			1,250,000
Line of credit facility amount outstanding	$ 841,328			$ 841,328		$ 744,431
Debt, Weighted Average Interest Rate	4.14%			4.14%
Pre-Tax SEC PV10 Reserve Value Percentage | Rate				90.00%
Federal funds rate plus percentage	0.50%			0.50%
Ratio of total debt to EBITDA				2.40
Current Ratio	1.73			1.73
Adjusted LIBO rate plus percentage	1.00%			1.00%
Senior Secured Revolving Credit Facility [Member] | Maximum [Member]
Debt Instrument [Line Items]
Ratio of total debt to EBITDA				4
Senior Secured Revolving Credit Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
Current Ratio	1			1
7.50% Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.50%			7.50%
Debt Instrument, Repurchased Face Amount			$ 320,000
Redemption price, percentage of principal amount			101.875%
8.25% Senior Notes [Member]
Debt Instrument [Line Items]
Long term debt	$ 250,000			$ 250,000		$ 250,000
Other Long Term Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.375%			4.375%
Debt Instrument, Repurchased Face Amount		$ 4,400			$ 4,400
Cash paid for debt redemption		4,500
Accrued interest paid associated with redemption of debt		$ 100
Redemption price, percentage of principal amount		100.00%			100.00%

Long-Term Debt (Schedule of Lon

Long-Term Debt (Schedule of Long-Term Debt) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Long-term debt	$ 1,731,418	$ 1,633,591
Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility amount outstanding	841,328	744,431
6.25% Senior Notes [Member]
Debt Instrument [Line Items]
Long term debt	650,000	650,000
Unamortized Debt Issuance Expense	(6,180)	(6,878)
8.25% Senior Notes [Member]
Debt Instrument [Line Items]
Long term debt	250,000	250,000
Unamortized Debt Issuance Expense	$ (3,730)	$ (3,962)

Long-Term Debt (Interest and Co

Long-Term Debt (Interest and Commitment Fee Rates) (Details) - Senior Secured Revolving Credit Facility [Member]	6 Months Ended
	Jun. 30, 2019
Less than 25 percent [Member]
Interest and Commitment Fee Rates [Line Items]
Margin for base rate loans	0.25%
Margin for eurodollar loans	1.25%
Line of Credit Facility, Commitment Fee Percentage	0.375%
Greater than or equal to 25 percent but less than 50 percent [Member]
Interest and Commitment Fee Rates [Line Items]
Margin for base rate loans	0.50%
Margin for eurodollar loans	1.50%
Line of Credit Facility, Commitment Fee Percentage	0.375%
Greater than or equal to 50 percent but less than 75 percent [Member]
Interest and Commitment Fee Rates [Line Items]
Margin for base rate loans	0.75%
Margin for eurodollar loans	1.75%
Line of Credit Facility, Commitment Fee Percentage	0.50%
Greater than or equal to 75 percent but less than 90 percent [Member]
Interest and Commitment Fee Rates [Line Items]
Margin for base rate loans	1.00%
Margin for eurodollar loans	2.00%
Line of Credit Facility, Commitment Fee Percentage	0.50%
Greater than or equal to 90 percent [Member]
Interest and Commitment Fee Rates [Line Items]
Margin for base rate loans	1.25%
Margin for eurodollar loans	2.25%
Line of Credit Facility, Commitment Fee Percentage	0.50%

Preferred Stock (Narrative) (De

Preferred Stock (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Jan. 24, 2018	Aug. 10, 2017
Preferred Stock Disclosure [Line Items]
Preferred Stock, Par Value									$ 250,000
Preferred Stock, Shares Issued	200,000				200,000		200,000		250,000
Preferred Stock, Par or Stated Value Per Share	$ 0.01				$ 0.01		$ 0.01
Issuance of warrants to purchase Common Stock				2,750,000
Class of Warrant or Right, Term				10 years
Class of Warrant or Right, Exercise Price of Warrants or Rights									$ 16.08
Cash purchase price per share of Preferred Stock									970
Temporary Equity, Liquidation Preference Per Share									$ 1,000
Maximum Preferred Stock Shares Redeemable Within the First Year									50,000
Preferred Stock Shares Redeemed								50,000
Preferred Stock, Percentage Redeemed								20.00%
Payments for Repurchase of Redeemable Preferred Stock			$ 50,500
Redemption Price of Preferred Stock			50,000
Loss on redemption of preferred stock	$ 0	$ 0	7,100		$ 0	$ 7,133
Redemption of Preferred Stock			42,900		$ 0	$ 42,897
Payments Of Accrued Dividends Upon Redemption Of Preferred Stock			$ 500
Carrizo [Member]
Preferred Stock Disclosure [Line Items]
Preferred Stock, Dividend Rate, Percentage				8.875%
Preferred Stock, Par or Stated Value Per Share									$ 0.01

Preferred Stock (Schedule of Di

Preferred Stock (Schedule of Dividends Paid in Common Stock) (Details)	Jun. 30, 2019Rate
Preferred Stock Dividend Paid in Common Stock Second Year [Member]
Schedule of Preferred Stock Dividend Paid in Common Stock [Line Items]
Percent of Dividend Payable in Common Stock	75.00%
Preferred Stock Dividend Paid in Common Stock Third Year [Member]
Schedule of Preferred Stock Dividend Paid in Common Stock [Line Items]
Percent of Dividend Payable in Common Stock	50.00%

Preferred Stock (Schedule of Pr

Preferred Stock (Schedule of Preferred Stock Activity) (Details) - USD ($)	3 Months Ended			6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Schedule of Preferred Stock Activity [Abstract]
Preferred stock, $0.01 par value, 10,000,000 shares authorized; 200,000 issued and outstanding as of June 30, 2019 and December 31, 2018	$ 176,056,000	$ 172,858,000		$ 176,056,000	$ 172,858,000	$ 174,422,000	$ 214,262,000
Redemption of Preferred Stock			$ (42,900,000)	0	(42,897,000)
Accretion on preferred stock	$ (833,000)	$ (740,000)		$ (1,634,000)	$ (1,493,000)

Shareholders' Equity and Stoc_3

Shareholders' Equity and Stock Incentive Plans (Narrative) (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Restricted Stock Awards And Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate Intrinsic Value, Vested	$ 700,000	$ 1,000,000	$ 10,500,000	$ 9,900,000
Nonvested Awards, Compensation Cost Not yet Recognized	38,300,000	30,500,000	$ 38,300,000	30,500,000
Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition			2 years 2 months 12 days
Restricted Stock Awards And Units [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, in years			3 years
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate Intrinsic Value, Outstanding	0	9,100,000	$ 0	9,100,000
Aggregate Intrinsic Value, Exercisable	0	500,000	0	500,000
Fair Value of Shares Issued			4,600,000	4,900,000
Nonvested Awards, Compensation Cost Not yet Recognized	5,100,000	11,300,000	$ 5,100,000	$ 11,300,000
Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition			2 years 4 months 24 days	2 years 7 months 6 days
Stock Appreciation Rights (SARs) [Member] | Other Current Liabilities [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Liability For Cash Stock Appreciation Rights			$ 2,100,000		$ 1,800,000
Stock Appreciation Rights (SARs) [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, in years			3 years
Expiration period after date of grant, in years			7 years
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair Value of Shares Issued			$ 1,900,000	$ 1,800,000
Vesting period, in years			3 years
Aggregate Intrinsic Value, Vested			$ 400,000	800,000
Nonvested Awards, Compensation Cost Not yet Recognized	$ 3,100,000	$ 2,900,000	$ 3,100,000	$ 2,900,000
Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition			2 years 1 month 6 days	2 years 2 months 12 days
Shares Of Common Stock Per Performance Shares Earned			1
Performance Shares [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award Vesting Rights Percentage Range			200.00%
Performance Shares [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award Vesting Rights Percentage Range			0.00%
2017 Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Available for Grant	3,164,691		3,164,691

Shareholders' Equity and Stoc_4

Shareholders' Equity and Stock Incentive Plans (Summary of Restricted Stock Award and Unit Activity) (Details) - Restricted Stock Awards And Units [Member] - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Restricted Stock Awards and Units [Abstract]
Unvested Shares/Units, Beginning of Period	3,320,060	2,263,830	2,266,667	1,482,655
Granted Shares/Units	115,936	1,250	2,034,619	1,348,415
Vested Shares/Units	(52,639)	(43,992)	(904,973)	(608,904)
Forfeited Shares/Units	(47,464)	(9,915)	(60,420)	(10,993)
Unvested Shares/Units, End of Period	3,335,893	2,211,173	3,335,893	2,211,173
Weighted Average Grant Date Fair Value [Abstract]
Grant Date Fair Value, Beginning of Period (USD per share)	$ 14.16	$ 19.15	$ 19.28	$ 28.07
Granted, Grant Date Fair Value (USD per share)	11.90	15.43	11.06	14.68
Vested, Grant Date Fair Value (USD per share)	25.20	25.76	20.91	31.43
Forfeited, Grant Date Fair Value (USD per share)	12.05	18.04	13.14	19.17
Grant Date Fair Value, End of Period (USD per share)	$ 13.94	$ 19.02	$ 13.94	$ 19.02

Shareholders' Equity and Stoc_5

Shareholders' Equity and Stock Incentive Plans (Summary of SARs Activity) (Details) - Stock Appreciation Rights (SARs) [Member] - $ / shares	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
SARs, Outstanding, Beginning of period	1,330,924	714,238
SARs, Granted	770,775	616,686
SARs, Exercised	0	0
SARs, Forfeitures	0	0
SARs, Expirations	0	0
SARs, Outstanding, End of period	2,101,699	1,330,924
SARs, Vested, End of Period	919,800	543,018
SARs, Exercisable, End of Period	0	543,018
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Weighted Average Exercise Price [Roll Forward]
Weighted Average Exercise Prices, Outstanding, Beginning of Period	$ 21.35	$ 27.12
Weighted Average Exercise Prices, Granted	10.98	14.67
Weighted Average Exercise Prices, Exercised	0	0
Weighted Average Exercise Prices, Forfeitures	0	0
Weighted Average Exercise Prices, Expired	0	0
Weighted Average Exercise Prices, Outstanding, End of Period	17.55	21.35
Weighted Average Exercise Prices, Vested, End of Period	24.34	27.18
Weighted Average Exercise Prices, Exercisable, End of Period	$ 24.34	$ 27.18
Weighted Average Remaining Life, Outstanding, End of Period	4 years 10 months 24 days	4 years 9 months 18 days
Weighted Average Remaining Life, Exercisable, End of Period	3 years	3 years

Shareholders' Equity and Stoc_6

Shareholders' Equity and Stock Incentive Plans (Summary of SARs Fair Value Assumptions) (Details) - Stock Appreciation Rights (SARs) [Member] - $ / shares	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected Term	6 years 1 month 6 days	6 years
Expected Volatility Rate	56.00%	54.30%
Risk-free Interest Rate	2.60%	2.80%
Dividend Yield	0.00%	0.00%
Granted, Grant Date Fair Value (USD per share)	$ 6	$ 7.89

Shareholders' Equity and Stoc_7

Shareholders' Equity and Stock Incentive Plans (Summary of Performance Share Award Activity) (Details) - Performance Shares [Member] - $ / shares	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Performance Share Awards
Unvested Shares/Units, Beginning of Period	182,209	144,955
Granted Shares/Units	130,302	93,771
Vested Shares/Units	(31,244)	(49,458)
Forfeited Shares/Units	0	0
Unearned Shares due to Market Condition	(10,407)	(7,059)
Unvested Shares/Units, End of Period	270,860	182,209
Weighted Average Grant Date Fair Value [Abstract]
Grant Date Fair Value, Beginning of Period (USD per share)	$ 27.01	$ 47.14
Granted, Grant Date Fair Value (USD per share)	14.20	19.09
Vested, Grant Date Fair Value (USD per share)	35.71	65.51
Forfeited, Grant Date Fair Value (USD per share)	0	0
Unearned Shares due to Market Condition, Weighted Average Grant Date Fair Value	35.71	65.51
Grant Date Fair Value, End of Period (USD per share)	$ 19.51	$ 27.01

Shareholders' Equity and Stoc_8

Shareholders' Equity and Stock Incentive Plans (Schedule of Results of Total Shareholder Return Ranking) (Details) - Performance Shares [Member] - USD ($)	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Target Performance Shares Granted	41,651	56,517
Vesting Percentage of Target Shares Granted	75.00%	88.00%
Vested Shares/Units	(31,244)	(49,458)
Unearned Shares due to Market Condition	10,407	7,059
Aggregate Intrinsic Value, Vested	$ 400,000	$ 800,000

Shareholders' Equity and Stoc_9

Shareholders' Equity and Stock Incentive Plans (Summary of Performance Share Awards Fair Value Assumptions) (Details) - Performance Shares [Member]	6 Months Ended
	Jun. 30, 2019$ / sharesRate	Jun. 30, 2018$ / sharesRate
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of simulations performed	500,000	500,000
Expected Term	3 years 1 month 6 days	3 years
Expected Volatility Rate	58.20%	61.50%
Risk-free Interest Rate	2.50%	2.40%
Dividend Yield	0.00%	0.00%
Granted, Grant Date Fair Value (USD per share) | $ / shares	$ 14.20	$ 19.09

Shareholders' Equity and Sto_10

Shareholders' Equity and Stock Incentive Plans (Schedule of Share-Based Compensation Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated Share-based Compensation Expense	$ 5,368	$ 10,914	$ 11,386	$ 15,140
Less: amounts capitalized	(1,514)	(3,708)	(3,417)	(4,416)
Share-based Compensation Arrangement, Compensation Cost	3,854	7,206	7,969	10,724
Restricted Stock Awards And Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated Share-based Compensation Expense	5,358	4,720	10,181	9,804
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated Share-based Compensation Expense	(426)	5,788	334	4,373
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated Share-based Compensation Expense	$ 436	$ 406	$ 871	$ 963

Earnings per Share (Schedule of

Earnings per Share (Schedule of Earnings per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Net Income (loss)	$ 107,485	$ 35,309		$ 258,848	$ 62,801
Dividends on preferred stock	(4,452)	(4,474)		(8,812)	(9,337)
Accretion on preferred stock	(833)	(740)		(1,634)	(1,493)
Loss on redemption of preferred stock	0	0	$ (7,100)	0	(7,133)
Net Income Attributable to Common Shareholders	$ 102,200	$ 30,095		$ 248,402	$ 44,838
Basic (in shares)	92,497	82,058		92,121	81,802
Dilutive effect of restricted stock and performance shares	203	967		358	798
Dilutive effect of common stock warrants	0	828		0	640
Diluted (in shares)	92,700	83,853		92,479	83,240
Net Income (Loss) - basic (in dollars per share)	$ 1.10	$ 0.37		$ 2.70	$ 0.55
Net Income (Loss) - diluted (in dollars per share)	$ 1.10	$ 0.36		$ 2.69	$ 0.54

Earnings per Share (Schedule _2

Earnings per Share (Schedule of Anti-dilutive Shares) (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	5,827	16	4,276	19
Restricted Stock and Performance Shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	3,077	16	1,526	19
Warrant [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	2,750	0	2,750	0

Derivative Instruments (Narrati

Derivative Instruments (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative [Line Items]
Payment for Contingent Consideration Liability, Financing Activities	$ 0	$ 0	$ 40,000	$ 0
Receipt For Contingent Consideration Asset, Financing Activities			10,000
ExL Acquisition
Derivative [Line Items]
Potential Future Payments For Contingent Consideration Liability Financing Activities			(2,300)
Payment for Contingent Consideration Liability, Financing Activities	0	0	50,000	0
Niobrara Divestiture
Derivative [Line Items]
Potential Future Cash Receipts For Contingent Consideration Asset Financing Activities			2,900
Receipt For Contingent Consideration Asset, Financing Activities	0	0	5,000	0
Marcellus Shale Divestiture
Derivative [Line Items]
Potential Future Cash Receipts For Contingent Consideration Asset Financing Activities			2,700
Receipt For Contingent Consideration Asset, Financing Activities			0
Utica Shale Divestiture
Derivative [Line Items]
Potential Future Cash Receipts For Contingent Consideration Asset Financing Activities			1,100
Receipt For Contingent Consideration Asset, Financing Activities	$ 0	$ 0	$ 5,000	$ 0

Derivative Instruments (Schedul

Derivative Instruments (Schedule of Crude Oil Derivative Positions) (Details) - Crude Oil	Jun. 30, 2019bbl / d$ / bbls
3Q 2019 | Fixed Price Swaps
Derivative [Line Items]
Derivative, Volumes (in Bbl/d) | bbl / d	5,000
Derivative, Swap Type, Fixed Price	64.80
3Q 2019 | Three-way Collars
Derivative [Line Items]
Derivative, Volumes (in Bbl/d) | bbl / d	27,000
Weighted Average Sub-Floor Price ($/Bbl)	41.67
Weighted Average Floor Price ($/Bbl)	50.96
Weighted Average Ceiling Price ($/Bbl)	74.23
3Q 2019 | Basis Swaps | LLS-Cushing WTI Price Differential
Derivative [Line Items]
Derivative, Volumes (in Bbl/d) | bbl / d	6,000
Weighted Average Fixed Price ($/Bbl)	5.16
3Q 2019 | Basis Swaps | Midland WTI-Cushing WTI Price Differential
Derivative [Line Items]
Derivative, Volumes (in Bbl/d) | bbl / d	9,100
Weighted Average Fixed Price ($/Bbl)	4.44
3Q 2019 | Call Option
Derivative [Line Items]
Derivative, Volumes (in Bbl/d) | bbl / d	3,875
Weighted Average Ceiling Price ($/Bbl)	81.07
4Q 2019 | Fixed Price Swaps
Derivative [Line Items]
Derivative, Volumes (in Bbl/d) | bbl / d	5,000
Derivative, Swap Type, Fixed Price	64.80
4Q 2019 | Three-way Collars
Derivative [Line Items]
Derivative, Volumes (in Bbl/d) | bbl / d	27,000
Weighted Average Sub-Floor Price ($/Bbl)	41.67
Weighted Average Floor Price ($/Bbl)	50.96
Weighted Average Ceiling Price ($/Bbl)	74.23
4Q 2019 | Basis Swaps | Midland WTI-Cushing WTI Price Differential
Derivative [Line Items]
Derivative, Volumes (in Bbl/d) | bbl / d	9,200
Weighted Average Fixed Price ($/Bbl)	4.64
4Q 2019 | Call Option
Derivative [Line Items]
Derivative, Volumes (in Bbl/d) | bbl / d	3,875
Weighted Average Ceiling Price ($/Bbl)	81.07
FY 2020 | Fixed Price Swaps
Derivative [Line Items]
Derivative, Volumes (in Bbl/d) | bbl / d	3,000
Derivative, Swap Type, Fixed Price	55.06
FY 2020 | Three-way Collars
Derivative [Line Items]
Derivative, Volumes (in Bbl/d) | bbl / d	12,000
Weighted Average Sub-Floor Price ($/Bbl)	45.63
Weighted Average Floor Price ($/Bbl)	55.63
Weighted Average Ceiling Price ($/Bbl)	66.04
FY 2020 | Basis Swaps | Midland WTI-Cushing WTI Price Differential
Derivative [Line Items]
Derivative, Volumes (in Bbl/d) | bbl / d	10,658
Weighted Average Fixed Price ($/Bbl)	1.68
FY 2020 | Call Option
Derivative [Line Items]
Derivative, Volumes (in Bbl/d) | bbl / d	4,575
Weighted Average Ceiling Price ($/Bbl)	75.98
FY 2021 | Basis Swaps | Midland WTI-Cushing WTI Price Differential
Derivative [Line Items]
Derivative, Volumes (in Bbl/d) | bbl / d	8,000
Weighted Average Fixed Price ($/Bbl)	0.18

Derivative Instruments (Sched_2

Derivative Instruments (Schedule of Natural Gas Derivative Positions) (Details) - Natural Gas	Jun. 30, 2019MMBTU / d$ / MMBTU
3Q 2019 | Basis Swaps
Derivative [Line Items]
Derivative, Volumes (in MMBtu/d) | MMBTU / d	42,500
Weighted Average Fixed Price ($/MMBtu) | $ / MMBTU	(1.49)
3Q 2019 | Call Option
Derivative [Line Items]
Derivative, Volumes (in MMBtu/d) | MMBTU / d	33,000
Weighted Average Ceiling Price ($/MMBtu) | $ / MMBTU	3.25
4Q 2019 | Basis Swaps
Derivative [Line Items]
Derivative, Volumes (in MMBtu/d) | MMBTU / d	42,500
Weighted Average Fixed Price ($/MMBtu) | $ / MMBTU	(1.30)
4Q 2019 | Call Option
Derivative [Line Items]
Derivative, Volumes (in MMBtu/d) | MMBTU / d	33,000
Weighted Average Ceiling Price ($/MMBtu) | $ / MMBTU	3.25
FY 2020 | Basis Swaps
Derivative [Line Items]
Derivative, Volumes (in MMBtu/d) | MMBTU / d	29,541
Weighted Average Fixed Price ($/MMBtu) | $ / MMBTU	(0.77)
FY 2020 | Call Option
Derivative [Line Items]
Derivative, Volumes (in MMBtu/d) | MMBTU / d	33,000
Weighted Average Ceiling Price ($/MMBtu) | $ / MMBTU	3.50

Derivative Instruments (Sched_3

Derivative Instruments (Schedule of Contingent Consideration) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)$ / bbls$ / MMBTU	Jun. 30, 2018USD ($)
Embedded Derivative [Line Items]
Divestiture date fair value of contingent consideration arrangement	$ 0	$ (7,880,000)	$ 0	$ (7,880,000)
Cash paid for settlements of contingent consideration arrangements, net	0	0	(40,000,000)	0
Receipt For Contingent Consideration Asset, Financing Activities			10,000,000
ExL Acquisition
Embedded Derivative [Line Items]
Contingent Consideration, Liability, Acquisition Date Fair Value	(52,300,000)		(52,300,000)
Cash paid for settlements of contingent consideration arrangements, net	0	0	(50,000,000)	0
Remaining Potential Contingent Consideration Payments	(75,000,000)		$ (75,000,000)
ExL Acquisition | FY 2018 [Member]
Embedded Derivative [Line Items]
Threshold Price per Bbl for Additional Payments for Acquisition | $ / bbls			50
ExL Acquisition | FY 2019 - 2021 [Member]
Embedded Derivative [Line Items]
Threshold Price per Bbl for Additional Payments for Acquisition | $ / bbls			50
Potential Additional Annual Payments for Acquisition			$ (50,000,000)
Niobrara Divestiture
Embedded Derivative [Line Items]
Divestiture date fair value of contingent consideration arrangement		7,880,000		7,880,000
Receipt For Contingent Consideration Asset, Financing Activities	0	0	5,000,000	0
Remaining Potential Contingent Consideration Receipts	10,000,000		$ 10,000,000
Niobrara Divestiture | FY 2018 [Member]
Embedded Derivative [Line Items]
Threshold Price Per Bbl For Additional Proceeds From Divestiture | $ / bbls			55
Niobrara Divestiture | FY 2019 [Member]
Embedded Derivative [Line Items]
Threshold Price Per Bbl For Additional Proceeds From Divestiture | $ / bbls			55
Potential Additional Annual Proceeds From Divestiture			$ 5,000,000
Niobrara Divestiture | FY 2020 [Member]
Embedded Derivative [Line Items]
Threshold Price Per Bbl For Additional Proceeds From Divestiture | $ / bbls			60
Potential Additional Annual Proceeds From Divestiture			$ 5,000,000
Marcellus Shale Divestiture
Embedded Derivative [Line Items]
Divestiture date fair value of contingent consideration arrangement		2,660,000		2,660,000
Receipt For Contingent Consideration Asset, Financing Activities			0
Remaining Potential Contingent Consideration Receipts	6,000,000		$ 6,000,000
Marcellus Shale Divestiture | FY 2018 [Member]
Embedded Derivative [Line Items]
Threshold Price per MMBtu for Additional Payments from Divestiture | $ / MMBTU			3.13
Marcellus Shale Divestiture | FY 2019 [Member]
Embedded Derivative [Line Items]
Threshold Price per MMBtu for Additional Payments from Divestiture | $ / MMBTU			3.18
Potential Additional Annual Proceeds From Divestiture			$ 3,000,000
Marcellus Shale Divestiture | FY 2020 [Member]
Embedded Derivative [Line Items]
Threshold Price per MMBtu for Additional Payments from Divestiture | $ / MMBTU			3.30
Potential Additional Annual Proceeds From Divestiture			$ 3,000,000
Utica Shale Divestiture
Embedded Derivative [Line Items]
Divestiture date fair value of contingent consideration arrangement		6,145,000		6,145,000
Receipt For Contingent Consideration Asset, Financing Activities	0	$ 0	5,000,000	$ 0
Remaining Potential Contingent Consideration Receipts	$ 10,000,000		$ 10,000,000
Utica Shale Divestiture | FY 2018 [Member]
Embedded Derivative [Line Items]
Threshold Price Per Bbl For Additional Proceeds From Divestiture | $ / bbls			50
Utica Shale Divestiture | FY 2019 [Member]
Embedded Derivative [Line Items]
Threshold Price Per Bbl For Additional Proceeds From Divestiture | $ / bbls			53
Potential Additional Annual Proceeds From Divestiture			$ 5,000,000
Utica Shale Divestiture | FY 2020 [Member]
Embedded Derivative [Line Items]
Threshold Price Per Bbl For Additional Proceeds From Divestiture | $ / bbls			56
Potential Additional Annual Proceeds From Divestiture			$ 5,000,000

Derivative Instruments (Sched_4

Derivative Instruments (Schedule of Derivative Instruments in Statement of Financial Position) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Derivative assets, current	$ 13,621	$ 39,904
Derivative liabilities, current	(64,751)	(55,205)
Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	21,704	50,406
Derivative Asset, Fair Value, Gross Liability	(15,582)	(20,502)
Derivative, Fair Value, Net	6,122	29,904
Derivative assets, current	13,621	39,904
Derivative Asset, Gross Asset	29,203	60,406
Derivative Asset, Gross Liability	(15,582)	(20,502)
Other Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	10,303	6,083
Derivative Asset, Fair Value, Gross Liability	(8,243)	(4,236)
Derivative, Fair Value, Net	2,060	1,847
Derivative Asset, Gross Asset	14,258	11,988
Derivative Asset, Gross Liability	(8,243)	(4,236)
Derivative assets, noncurrent	6,015	7,752
Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net	(18,366)	(5,205)
Derivative Liability, Fair Value, Gross Liability	(26,390)	(15,345)
Derivative Liability, Fair Value, Gross Asset	8,024	10,140
Derivative liabilities, current	(64,751)	(55,205)
Derivative Deferred Premium, Net	0	0
Derivative Liability, Deferred Premiums, Gross Liability	(7,558)	(10,362)
Derivative Liability, Gross Liability	(80,333)	(75,707)
Derivative Liability, Deferred Premiums, Gross Asset	7,558	10,362
Derivative Liability, Gross Asset	15,582	20,502
Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net	(4,514)	(10,233)
Derivative Liability, Fair Value, Gross Liability	(10,988)	(10,751)
Derivative Liability, Fair Value, Gross Asset	6,474	518
Derivative Deferred Premium, Net	0	0
Derivative Liability, Deferred Premiums, Gross Liability	(1,769)	(3,718)
Derivative Liability, Gross Liability	(27,170)	(45,053)
Derivative Liability, Deferred Premiums, Gross Asset	1,769	3,718
Derivative Liability, Gross Asset	8,243	4,236
Derivative liabilities, noncurrent	(18,927)	(40,817)
Niobrara Divestiture | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Contingent Payment, Gross Liability	0	0
Contingent Consideration, Current Asset	3,409	5,000
Niobrara Divestiture | Other Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Business Combination, Contingent Consideration, Asset, Noncurrent	1,538	2,035
Derivative Asset, Contingent Payment, Gross Liability	0	0
Marcellus Shale Divestiture | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Contingent Payment, Gross Liability	0
Contingent Consideration, Current Asset	3
Marcellus Shale Divestiture | Other Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Business Combination, Contingent Consideration, Asset, Noncurrent	447	1,369
Derivative Asset, Contingent Payment, Gross Liability	0	0
Utica Shale Divestiture | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Contingent Payment, Gross Liability	0	0
Contingent Consideration, Current Asset	4,087	5,000
Utica Shale Divestiture | Other Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Business Combination, Contingent Consideration, Asset, Noncurrent	1,970	2,501
Derivative Asset, Contingent Payment, Gross Liability	0	0
ExL Acquisition | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Business Combination, Contingent Consideration, Liability, Current	(46,385)	(50,000)
Derivative Liability, Contingent Payment, Gross Asset	0	0
ExL Acquisition | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Contingent Payment, Gross Liability	(14,413)	(30,584)
Derivative Liability, Contingent Payment, Gross Asset	0	0
Business Combination, Contingent Consideration, Liability, Noncurrent	$ (14,413)	$ (30,584)

Derivative Instruments (Sched_5

Derivative Instruments (Schedule of (Gain) Loss on Derivative Instruments) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative Instruments, Gain (Loss), Commodity [Line Items]
(Gain) loss on derivatives, net	$ (20,449)	$ 67,714	$ 62,835	$ 97,310
Crude Oil
Derivative Instruments, Gain (Loss), Commodity [Line Items]
(Gain) loss on derivatives, net	(20,915)	53,437	41,846	82,948
Natural Gas Liquids
Derivative Instruments, Gain (Loss), Commodity [Line Items]
(Gain) loss on derivatives, net	0	6,564	(6)	4,799
Natural Gas
Derivative Instruments, Gain (Loss), Commodity [Line Items]
(Gain) loss on derivatives, net	(1,600)	153	(3,670)	(2,892)
ExL Acquisition
Derivative Instruments, Gain (Loss), Commodity [Line Items]
Gain (Loss) on Embedded Derivative, Net	1,215	10,600	30,214	16,430
Niobrara Divestiture
Derivative Instruments, Gain (Loss), Commodity [Line Items]
Gain (Loss) on Embedded Derivative, Net	265	(1,705)	(2,912)	(2,090)
Marcellus Shale Divestiture
Derivative Instruments, Gain (Loss), Commodity [Line Items]
Gain (Loss) on Embedded Derivative, Net	438	205	919	675
Utica Shale Divestiture
Derivative Instruments, Gain (Loss), Commodity [Line Items]
Gain (Loss) on Embedded Derivative, Net	$ 148	$ (1,540)	$ (3,556)	$ (2,560)

Derivative Instruments (Sched_6

Derivative Instruments (Schedule of Cash Received for Derivative Settlements) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Schedule Of Cash Received For Derivatives [Line Items]
Cash paid for commodity derivative settlements, net	$ (4,522)	$ (24,083)	$ (7,160)	$ (38,448)
Cash paid for settlements of contingent consideration arrangements, net	0	0	(40,000)	0
Receipt For Contingent Consideration Asset, Financing Activities			10,000
Crude Oil
Schedule Of Cash Received For Derivatives [Line Items]
Cash paid for commodity derivative settlements, net	(3,698)	(21,210)	(4,018)	(33,333)
Natural Gas Liquids
Schedule Of Cash Received For Derivatives [Line Items]
Cash paid for commodity derivative settlements, net	0	(756)	623	(1,188)
Natural Gas
Schedule Of Cash Received For Derivatives [Line Items]
Cash paid for commodity derivative settlements, net	1,925	488	1,625	540
Deferred Premiums on Derivative Instruments
Schedule Of Cash Received For Derivatives [Line Items]
Cash paid for commodity derivative settlements, net	(2,749)	(2,605)	(5,390)	(4,467)
ExL Acquisition
Schedule Of Cash Received For Derivatives [Line Items]
Cash paid for settlements of contingent consideration arrangements, net	0	0	(50,000)	0
Niobrara Divestiture
Schedule Of Cash Received For Derivatives [Line Items]
Receipt For Contingent Consideration Asset, Financing Activities	0	0	5,000	0
Utica Shale Divestiture
Schedule Of Cash Received For Derivatives [Line Items]
Receipt For Contingent Consideration Asset, Financing Activities	$ 0	$ 0	$ 5,000	$ 0

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($)	Jun. 30, 2019	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value, Assets, Level 2 to Level 1 Transfers, Amount	$ 0	$ 0
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount	0	0
Fair Value, Assets, Level 3 Transfers	$ 0	$ 0

Fair Value Measurements (Schedu

Fair Value Measurements (Schedule of Assets and Liabilities Measured on Recurring Basis) (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	$ 0	$ 0
Derivative Liability	0	0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	8,182	31,751
Derivative Liability	(22,880)	(15,438)
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0	0
Derivative Liability	0	0
Niobrara Divestiture | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0	0
Niobrara Divestiture | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	4,947	7,035
Niobrara Divestiture | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0	0
Marcellus Shale Divestiture | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0	0
Marcellus Shale Divestiture | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	450	1,369
Marcellus Shale Divestiture | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0	0
Utica Shale Divestiture | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0	0
Utica Shale Divestiture | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	6,057	7,501
Utica Shale Divestiture | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0	0
ExL Acquisition | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	0	0
ExL Acquisition | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	(60,798)	(80,584)
ExL Acquisition | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	$ 0	$ 0

Fair Value Measurements (Sche_2

Fair Value Measurements (Schedule of Carrying Value and Fair Value of Debt Instruments) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
6.25% Senior Notes [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	$ 650,000	$ 650,000
6.25% Senior Notes [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	626,438	599,625
8.25% Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	250,000	250,000
8.25% Senior Notes [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	250,000	250,000
8.25% Senior Notes [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	$ 244,063	$ 244,375

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information (Supplemental Cash Flow Disclosures) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Supplemental Cash Flow Elements [Abstract]
Interest Paid, Excluding Capitalized Interest, Operating Activities			$ 34,475	$ 29,853
Income Taxes Paid			590	0
Change in capital expenditure payables and accruals			28,428	35,543
Divestiture date fair value of contingent consideration arrangement	$ 0	$ (7,880)	0	(7,880)
Share-based Compensation, Capitalized Amount	$ 1,514	$ 3,708	3,417	4,416
Costs Incurred, Asset Retirement Obligation Incurred			3,324	691
Non Cash Gain Loss On Extinguishment Of Debt			$ 0	$ 2,666