Carrizo Oil & Gas (CRZO) 10-Q 7 Aug 18 2018 Q2 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Aug. 01, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Entity Registrant Name	CARRIZO OIL & GAS INC
Entity Central Index Key	1,040,593
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		82,114,492

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 2,099,000	$ 9,540,000
Accounts receivable, net	111,100,000	107,441,000
Derivative assets, current	10,928,000
Other current assets	8,378,000	5,897,000
Total current assets	132,505,000	122,878,000
Oil and gas properties, full cost method
Proved properties, net	1,959,951,000	1,965,347,000
Unproved properties, not being amortized	597,892,000	660,287,000
Other property and equipment, net	10,582,000	10,176,000
Total property and equipment, net	2,568,425,000	2,635,810,000
Other assets	20,909,000	19,616,000
Total Assets	2,721,839,000	2,778,304,000
Current liabilities
Accounts payable	113,651,000	74,558,000
Revenues and royalties payable	53,280,000	52,154,000
Accrued capital expenditures	117,934,000	119,452,000
Accrued interest	21,126,000	28,362,000
Derivative liabilities	145,520,000	57,121,000
Other current liabilities	52,020,000	41,175,000
Total current liabilities	503,531,000	372,822,000
Long-term debt	1,502,307,000	1,629,209,000
Asset retirement obligations	16,305,000	23,497,000
Derivative liabilities, noncurrent	87,933,000	112,332,000
Deferred income tax liabilities, noncurrent	4,164,000	3,635,000
Other liabilities	8,273,000	51,650,000
Liabilities	2,122,513,000	2,193,145,000
Preferred stock, $0.01 par value, 10,000,000 shares authorized; 200,000 issued and outstanding as of June 30, 2018 and 250,000 issued and outstanding as of December 31, 2017	172,858,000	214,262,000
Shareholders’ equity
Common stock, $0.01 par value, 180,000,000 shares authorized; 82,107,544 issued and outstanding as of June 30, 2018 and 81,454,621 issued and outstanding as of December 31, 2017	821,000	815,000
Additional paid-in capital	1,918,820,000	1,926,056,000
Accumulated deficit	(1,493,173,000)	(1,555,974,000)
Total shareholders’ equity	426,468,000	370,897,000
Total Liabilities and Shareholders’ Equity	$ 2,721,839,000	$ 2,778,304,000

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	180,000,000	180,000,000
Common stock, shares issued (in shares)	82,107,544	81,454,621
Common stock, shares outstanding (in shares)	82,107,544	81,454,621
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	250,000
Preferred Stock, Shares Outstanding	200,000	250,000

Consolidated Statements Of Oper

Consolidated Statements Of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Crude oil revenues	$ 229,798	$ 142,806	$ 424,717	$ 270,898
Natural gas liquids revenues	21,269	7,786	38,171	15,211
Natural gas revenues	12,906	15,891	26,365	31,729
Total revenues	263,973	166,483	489,253	317,838
Costs and Expenses
Lease operating	35,151	36,048	74,424	65,893
Production taxes	12,487	7,143	23,062	13,351
Ad valorem taxes	3,640	1,073	5,613	4,040
Depreciation, depletion and amortization	72,430	59,072	136,897	113,454
General and administrative, net	18,265	11,596	45,557	33,299
(Gain) loss on derivatives, net	67,714	(26,065)	97,310	(51,381)
Interest expense, net	15,599	21,106	31,116	41,677
Loss on extinguishment of debt	0	0	8,676	0
Other expense, net	2,895	204	2,995	1,178
Total Costs and Expenses	228,181	110,177	425,650	221,511
Income Before Income Taxes	35,792	56,306	63,603	96,327
Income tax expense	(483)	0	(802)	0
Net Income (loss)	35,309	56,306	62,801	96,327
Dividends on preferred stock	(4,474)	0	(9,337)	0
Accretion on preferred stock	(740)	0	(1,493)	0
Loss on redemption of preferred stock	0	0	(7,133)	0
Net Income Attributable to Common Shareholders	$ 30,095	$ 56,306	$ 44,838	$ 96,327
Net Income Attributable to Common Shareholders Per Common Share
Income (loss) per share, basic (in dollars per share)	$ 0.37	$ 0.86	$ 0.55	$ 1.47
Income (loss) per share, diluted (in dollars per share)	$ 0.36	$ 0.85	$ 0.54	$ 1.46
Weighted Average Common Shares Outstanding
Basic (in shares)	82,058	65,767	81,802	65,479
Diluted (in shares)	83,853	65,908	83,240	65,866

Consolidated Statements Of Shar

Consolidated Statements Of Shareholders' Equity - 6 months ended Jun. 30, 2018 - 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]
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, net of forfeitures, and vestings of restricted stock units and performance shares, shares		652,923
Payments of 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

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Net income (loss)	$ 62,801	$ 96,327
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation, depletion and amortization	136,897	113,454
(Gain) loss on derivatives, net	97,310	(51,381)
Cash (paid) received for derivative settlements, net	(38,448)	1,258
Loss on extinguishment of debt	8,676	0
Stock-based compensation expense, net	10,724	3,596
Deferred income taxes	529	0
Non-cash interest expense, net	1,262	2,074
Other, net	3,975	2,767
Changes in components of working capital and other assets and liabilities-
Accounts receivable	2,437	(8,094)
Accounts payable	3,878	14,486
Accrued liabilities	(12,883)	5,650
Other assets and liabilities, net	(1,286)	(982)
Net cash provided by operating activities	275,872	179,155
Cash Flows From Investing Activities
Capital expenditures	(430,639)	(290,625)
Acquisitions of oil and gas properties	0	(16,533)
Deposit for pending acquisition of oil and gas properties	0	(75,000)
Proceeds from divestitures of oil and gas properties, net	345,789	18,201
Other, net	(1,096)	(2,479)
Net cash used in investing activities	(85,946)	(366,436)
Cash Flows From Financing Activities
Redemptions of senior notes	(330,435)	0
Redemption of preferred stock	(50,030)	0
Borrowings under credit agreement	1,126,856	919,097
Repayments of borrowings under credit agreement	(933,156)	(723,797)
Payments of debt issuance costs	(627)	(4,368)
Payment of Commitment Fees for Preferred Stock	0	(5,000)
Payments of dividends on preferred stock	(9,337)	0
Other, net	(638)	(617)
Net cash provided by (used in) financing activities	(197,367)	185,315
Net Decrease in Cash and Cash Equivalents	(7,441)	(1,966)
Cash and Cash Equivalents, Beginning of Period	9,540	4,194
Cash and Cash Equivalents, End of Period	$ 2,099	$ 2,228

Nature Of Operations

Nature Of Operations	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature Of Operations	1. Basis of Presentation Nature of Operations Carrizo Oil & Gas, Inc. is a Houston-based energy company which, together with its subsidiaries (collectively, the “Company”), 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. Consolidated Financial Statements 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. These financial statements and related notes included in this Quarterly Report on Form 10-Q should be read in conjunction with the Company’s audited Consolidated Financial Statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 (“ 2017 Annual Report”). Except as disclosed herein, there have been no material changes to the information disclosed in the notes in the 2017 Annual Report. 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.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Summary Of Significant Accounting Policies	2. Summary of Significant Accounting Policies Revenue Recognition Impact of ASC 606 Adoption . Effective January 1, 2018, the Company adopted ASU No. 2014-09, Revenue From Contracts With Customers (Topic 606) (“ASC 606”) using the modified retrospective method and has applied the standard to all existing contracts. ASC 606 supersedes previous revenue recognition requirements in ASC 605 - Revenue Recognition (“ASC 605”) and includes a five-step revenue recognition model to depict the transfer of goods or services to customers in an amount that reflects the consideration in exchange for those goods or services. As a result of adopting ASC 606, the Company did not have a cumulative-effect adjustment in retained earnings. The comparative information for the three and six months ended June 30, 2017 has not been recast and continues to be reported under the accounting standards in effect for that period. Additionally, adoption of ASC 606 did not impact net income attributable to common shareholders and the Company does not expect that it will do so in future periods. The tables below summarizes the impact of adoption for the three and six months ended June 30, 2018 : Three Months Ended June 30, 2018 Under ASC 606 Under ASC 605 Increase % Increase (In thousands) Revenues Crude oil $229,798 $229,658 $140 0.1 % Natural gas liquids 21,269 20,139 1,130 5.6 % Natural gas 12,906 12,272 634 5.2 % Total revenues 263,973 262,069 1,904 0.7 % Costs and Expenses Lease operating 35,151 33,247 1,904 5.7 % Income Before Income Taxes $35,792 $35,792 $— — % Six Months Ended June 30, 2018 Under ASC 606 Under ASC 605 Increase % Increase (In thousands) Revenues Crude oil $424,717 $424,452 $265 0.1 % Natural gas liquids 38,171 36,235 1,936 5.3 % Natural gas 26,365 25,159 1,206 4.8 % Total revenues 489,253 485,846 3,407 0.7 % Costs and Expenses Lease operating 74,424 71,017 3,407 4.8 % Income Before Income Taxes $63,603 $63,603 $— — % Changes to crude oil, NGL, and natural gas revenues and lease operating expense are due to the conclusion that the Company controls the product throughout processing before transferring to the customer for certain natural gas processing arrangements. Therefore, any transportation, gathering, and processing fees incurred prior to transfer of control are included in lease operating expense. 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 our 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, 2018 and December 31, 2017 , receivables from contracts with customers were $87.1 million and $85.6 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 income. Crude oil sales. Crude oil production is primarily sold at the wellhead at an agreed upon index price, net of pricing differentials. Revenue is recognized when control transfers to the purchaser at the wellhead, net of transportation costs incurred by the purchaser. Natural gas and NGL sales. Natural gas is delivered to a midstream processing entity at the wellhead or the inlet of the midstream processing entity’s system. The midstream processing entity gathers and processes the natural gas and remits proceeds for the resulting sales of NGLs and residue gas. The Company evaluates whether it is the principal or agent in the transaction and has concluded it is the principal and the ultimate third party is the customer. Revenue is recognized on a gross basis, with gathering, processing and transportation fees presented in “Lease operating expense” in the consolidated statements of income as the Company maintains control throughout processing. Transaction Price Allocated to Remaining Performance Obligations . The Company applied the practical expedient in ASC 606 exempting the disclosure of the transaction price allocated to remaining performance obligations if the variable consideration is allocated entirely to a wholly unsatisfied performance obligation. Each unit of product typically represents a separate performance obligation, therefore, future volumes are wholly unsatisfied and disclosure of the transaction price allocated to remaining performance obligations is not required. Recently Adopted Accounting Pronouncements Business Combinations. In January 2017, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business (“ASU 2017-01”), which clarifies the definition of a business to assist entities with evaluating whether transactions should be accounted for as acquisitions (or divestitures) of assets or businesses. Effective January 1, 2018, the Company adopted ASU 2017-01 using the prospective method and will apply the clarified definition of a business to future acquisition and divestitures. Statement of Cash Flows. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (“ASU 2016-15”), which is intended to reduce diversity in practice in how certain transactions are classified in the statement of cash flows. The guidance addresses eight specific cash flow issues for which current GAAP is either unclear or does not include specific guidance. Effective January 1, 2018, the Company adopted ASU 2016-15 using the retrospective approach as prescribed by ASU 2016-15. There were no changes to the statement of cash flows as a result of adoption. Recently Issued Accounting Pronouncements Leases. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (“ASU 2016-02”), which significantly changes accounting for leases by requiring that lessees recognize a right-of-use asset and a related lease liability representing the obligation to make lease payments, for virtually all lease transactions. ASU 2016-02 does not apply to leases of mineral rights to explore for or use crude oil and natural gas. Additional disclosures about an entity’s lease transactions will also be required. ASU 2016-02 defines a lease as “a contract, or part of a contract, that conveys the right to control the use of identified property, plant or equipment (an identified asset) for a period of time in exchange for consideration.” ASU 2016-02 is effective for interim and annual periods beginning after December 15, 2018 with early adoption permitted. ASU 2016-02 requires companies to recognize and measure leases at the beginning of the earliest period presented in the financial statements using a modified retrospective approach. The Company is in the process of reviewing and determining the contracts to which ASU 2016-02 applies with the assistance of a third party consultant. These include contracts such as non-cancelable leases, drilling rig contracts, pipeline gathering, transportation and gas processing agreements, and contracts for the use of vehicles and well equipment. The Company continues to review current accounting policies, controls, processes, and disclosures that will change as a result of adopting the new standard. Based upon its initial assessment, the Company expects the adoption of ASU 2016-02 will result in: (i) an increase in assets and liabilities due to the required recognition of right-of-use (“ROU”) assets and corresponding lease liabilities, (ii) increases in depreciation, depletion and amortization and interest expense, (iii) decreases in lease operating and general and administrative expense and (iv) additional disclosures, however, the full impact to the Company’s consolidated financial statements and related disclosures is still being evaluated. Currently, the Company plans to make certain elections allowing the Company not to reassess contracts that commenced prior to adoption, to continue applying its current accounting policy for land easements, and not to recognize ROU assets or lease liabilities for short-term leases. The Company plans to adopt the guidance on the effective date of January 1, 2019. As permitted by ASU No. 2018-11, Leases (Topic 842): Targeted Improvements, the Company does not expect to adjust comparative-period financial statements. Other than as disclosed above or in the Company’s 2017 Form 10-K, there are no other accounting standard updates applicable to the Company that would have a material effect on the Company’s consolidated financial statements and related disclosures that have been issued but not yet adopted by the Company as of June 30, 2018, and through the filing of this report. Net Income Attributable to Common Shareholders Per Common Share Supplemental net income attributable to common shareholders per common share information is provided below: Three Months Ended Six Months Ended 2018 2017 2018 2017 (In thousands, except per share amounts) Net Income Attributable to Common Shareholders $30,095 $56,306 $44,838 $96,327 Basic weighted average common shares outstanding 82,058 65,767 81,802 65,479 Effect of dilutive instruments 1,795 141 1,438 387 Diluted weighted average common shares outstanding 83,853 65,908 83,240 65,866 Net Income Attributable to Common Shareholders Per Common Share Basic $0.37 $0.86 $0.55 $1.47 Diluted $0.36 $0.85 $0.54 $1.46 The table below presents the a reconciliation of the basic weighted average common shares outstanding to diluted weighted average common shares outstanding for the three and six months ended June 30, 2018 and 2017 : Three Months Ended Six Months Ended 2018 2017 2018 2017 (In thousands) Basic weighted average common shares outstanding 82,058 65,767 81,802 65,479 Dilutive unvested restricted stock awards and units 833 141 640 387 Dilutive unvested performance shares 134 — 158 — Dilutive exercisable common stock warrants 828 — 640 — Diluted weighted average common shares outstanding 83,853 65,908 83,240 65,866 The table below presents a summary of the common shares outstanding that were excluded from the computation of diluted net income attributable to common shareholders per common share for the three and six months ended June 30, 2018 and 2017 , as their inclusion would be anti-dilutive: Three Months Ended Six Months Ended 2018 2017 2018 2017 (In thousands) Anti-dilutive unvested restricted stock awards and units 16 101 17 16 Anti-dilutive unvested performance shares — 108 2 62 Anti-dilutive exercisable common stock warrants — — — — Total anti-dilutive 16 209 19 78

Acquisitions and Divestitures

Acquisitions and Divestitures	6 Months Ended
	Jun. 30, 2018
Acquisitions and Divestitures [Abstract]
Acquisition and Divestiture Disclosures	3. Acquisitions and Divestitures of Oil and Gas Properties Acquisitions ExL Acquisition. On August 10, 2017, the Company closed on the acquisition of oil and gas properties located in the Delaware Basin in Reeves and Ward Counties, Texas (the “ExL Properties”) from ExL Petroleum Management, LLC and ExL Petroleum Operating Inc. (together “ExL”) for aggregate cash consideration of $679.8 million (the “ExL Acquisition”). See “Note 10. Derivative Instruments” for information regarding the contingent consideration arrangement associated with the ExL Acquisition. The consolidated statements of income for the three and six months ended June 30, 2018 include total revenues and net income attributable to common shareholders from the ExL Acquisition, representing activity of the acquired properties as shown in the table below: Three Months Ended Six Months Ended June 30, 2018 (In thousands) Total revenues $52,771 $96,239 Net income attributable to common shareholders $42,048 $76,851 Divestitures Eagle Ford. On January 31, 2018, the Company sold a portion of its assets in the Eagle Ford Shale to EP Energy E&P Company, L.P. The Company received aggregate net proceeds of $245.7 million , which represents an agreed upon price of $245.0 million plus purchase price adjustments, which were primarily related to the net cash flows from the effective date to the closing date. Niobrara. On January 19, 2018, the Company sold substantially all of its assets in the Niobrara Formation. Estimated aggregate net proceeds are $134.7 million , subject to post-closing adjustments. See “Note 10. Derivative Instruments” for information regarding the contingent consideration arrangement associated with this divestiture. The aggregate net proceeds for each of the divestitures above were recognized as a reduction of proved oil and gas properties. Marcellus. Effective August 2008, the Company’s wholly-owned subsidiary, Carrizo (Marcellus) LLC, entered into a joint venture with ACP II Marcellus LLC (“ACP II”), an affiliate of Avista Capital Partners, LP, a private equity fund (Avista Capital Partners, LP, together with its affiliates, “Avista”). As of June 30, 2018, the Avista Marcellus joint venture holds no material assets or obligations, has no interest in any wells or leases, and intends to divest all remaining immaterial assets. There have been no revenues, expenses, or operating cash flows in the Avista Marcellus joint venture during the years ended December 31, 2015, 2016 and 2017 or during the six months ended June 30, 2018. Concurrently with the sale of the remaining immaterial assets, the Avista Marcellus joint venture and associated joint venture agreements will terminate. Steven A. Webster, Chairman of the Company’s Board of Directors, serves as Co-Managing Partner and President of Avista Capital Holdings, LP. ACP II’s Board of Managers has the sole authority for determining whether, when and to what extent any cash distributions will be declared and paid to members of ACP II. Mr. Webster is not a member of ACP II’s Board of Managers. The terms of the Avista Marcellus joint venture were approved by a special committee of the Company’s independent directors.

Property And Equipment, Net

Property And Equipment, Net	6 Months Ended
	Jun. 30, 2018
Property, Plant and Equipment [Abstract]
Property And Equipment, Net	4. Property and Equipment, Net As of June 30, 2018 and December 31, 2017 , total property and equipment, net consisted of the following: June 30, December 31, (In thousands) Oil and gas properties, full cost method Proved properties $5,744,434 $5,615,153 Accumulated depreciation, depletion and amortization and impairments (3,784,483 ) (3,649,806 ) Proved properties, net 1,959,951 1,965,347 Unproved properties, not being amortized Unevaluated leasehold and seismic costs 539,836 612,589 Capitalized interest 58,056 47,698 Total unproved properties, not being amortized 597,892 660,287 Other property and equipment 27,223 25,625 Accumulated depreciation (16,641 ) (15,449 ) Other property and equipment, net 10,582 10,176 Total property and equipment, net $2,568,425 $2,635,810 Average depreciation, depletion and amortization (“DD&A”) per Boe of proved properties was $13.74 and $12.43 for the three months ended June 30, 2018 and 2017 , respectively, and $13.73 and $12.55 for the six months ended June 30, 2018 and 2017 , respectively. The Company capitalized internal costs of employee compensation and benefits, including stock-based compensation, directly associated with acquisition, exploration and development activities totaling $6.1 million and $1.9 million for the three months ended June 30, 2018 and 2017 , respectively, and $12.7 million and $7.3 million for the six months ended June 30, 2018 and 2017 , 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 $8.7 million and $4.0 million for the three months ended June 30, 2018 and 2017 , respectively, and $19.1 million and $7.8 million for the six months ended June 30, 2018 and 2017 , respectively.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	5. 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, except for discrete items, which are significant, unusual or infrequent items for which income taxes are computed and recorded in the interim period in which the discrete item occurs. The estimated annual effective income tax rates are applied to the year-to-date income or loss before income taxes by taxing jurisdiction to determine the income tax expense or benefit allocated to the interim period. The Company updates its estimated annual effective income tax rates on a quarterly basis considering the geographic mix of the estimated annual income or loss attributable to the tax jurisdictions in which the Company operates. The Company’s income tax expense differs from the income tax expense computed by applying the U.S. federal statutory corporate income tax rate of 21% for the three and six months ended June 30, 2018 and 35% for the three and six months ended June 30, 2017, to income before income taxes as follows: Three Months Ended Six Months Ended 2018 2017 2018 2017 (In thousands) Income before income taxes $35,792 $56,306 $63,603 $96,327 Income tax expense at the statutory rate (7,517 ) (19,707 ) (13,357 ) (33,714 ) State income tax expense, net of U.S. federal income taxes (487 ) (1,017 ) (806 ) (1,727 ) Tax shortfalls from stock-based compensation expense (16 ) (164 ) (2,542 ) (2,756 ) Decrease in deferred tax assets valuation allowance 8,048 20,948 16,449 38,317 Other (511 ) (60 ) (546 ) (120 ) Income tax expense ($483 ) $— ($802 ) $— Significant changes in the Company’s operations, including the ExL Acquisition in the Delaware Basin in the third quarter of 2017 and divestitures of substantially all of the Company’s assets in the Utica and Marcellus in the fourth quarter of 2017 and the Niobrara in the first quarter of 2018, resulted in changes to the Company’s state apportionment for estimated state deferred tax liabilities. As a result of these changes, the Company recorded current and deferred state income tax expense of $0.5 million and $0.8 million for the three and six months ended June 30, 2018 , respectively. Tax Cuts and Jobs Act On December 22, 2017, the U.S. Congress enacted the Tax Cuts and Jobs Act (the “Act”) which made significant changes to U.S. federal income tax law, including lowering the U.S. federal statutory corporate income tax rate to 21% from 35% beginning January 1, 2018. Due to the uncertainty regarding the application of ASC 740 in the period of enactment of the Act, the SEC issued Staff Accounting Bulletin 118 which allowed the Company to provide a provisional estimate of the impacts of the Act in earnings for the year ended December 31, 2017 and also provided a one-year measurement period in which the Company would record additional impacts from the enactment of the Act as they are identified. As of June 30, 2018 , the Company has not made any changes to the provisional estimate recorded in earnings for the year ended December 31, 2017. While the Company has made a reasonable estimate of the effects on its existing deferred tax balances, it has not completed its accounting for the tax effects of the enactment of the Act and will continue to monitor provisions with discrete rate impacts, such as the limitation on executive compensation for subsequent events and additional guidance provided within the one year measurement period. Deferred Tax Assets Valuation Allowance Primarily as a result of the impairments of proved oil and gas properties recognized beginning in the third quarter of 2015 and continuing through the third quarter of 2016, the Company had a cumulative historical three year pre-tax loss and a net deferred tax asset position at June 30, 2018. The Company then assessed the realizability of its deferred tax assets and, beginning in the third quarter of 2015 and continuing through the second quarter of 2018, the Company concluded that it was more likely than not the deferred tax assets will not be realized and that a valuation allowance was required to reduce the net deferred tax assets to zero . As of June 30, 2018 and December 31, 2017, the valuation allowance was $316.5 million and $333.0 million , respectively. See the table above for changes in the valuation allowance for the three and six months ended June 30, 2018 and 2017, which primarily related to activity during each respective period and, for the three and six months ended June 30, 2017, the effect of adopting ASU 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting.

Long-Term Debt

Long-Term Debt	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Debt	6. Long-Term Debt Long-term debt consisted of the following as of June 30, 2018 and December 31, 2017 : June 30, December 31, (In thousands) Senior Secured Revolving Credit Facility due 2022 $485,000 $291,300 7.50% Senior Notes due 2020 130,000 450,000 Unamortized premium for 7.50% Senior Notes 139 579 Unamortized debt issuance costs for 7.50% Senior Notes (1,095 ) (4,492 ) 6.25% Senior Notes due 2023 650,000 650,000 Unamortized debt issuance costs for 6.25% Senior Notes (7,554 ) (8,208 ) 8.25% Senior Notes due 2025 250,000 250,000 Unamortized debt issuance costs for 8.25% Senior Notes (4,183 ) (4,395 ) Other long-term debt due 2028 — 4,425 Long-term debt $1,502,307 $1,629,209 Senior Secured Revolving Credit Facility The Company has a senior secured revolving credit facility with a syndicate of banks that, as of June 30, 2018 , had a borrowing base of $1.0 billion , with an elected commitment amount of $900.0 million , and borrowings outstanding of $485.0 million at a weighted average interest rate of 3.74% . The credit agreement governing the revolving credit facility provides for interest-only payments until May 4, 2022 (subject to a springing maturity date of June 15, 2020 if the 7.50% Senior Notes due 2020 (the “ 7.50% Senior Notes”) have not been redeemed or refinanced on or prior to such time), 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 January 31, 2018, as a result of the divestiture in the Eagle Ford Shale discussed above, the Company’s borrowing base under the senior secured revolving credit facility was reduced from $900.0 million to $830.0 million , however, the elected commitment amount remained unchanged at $800.0 million . On May 4, 2018, the Company entered into the twelfth amendment to its credit agreement governing the revolving credit facility to, among other things, (i) establish the borrowing base at $1.0 billion , with an elected commitment amount of $900.0 million , until the next redetermination thereof, (ii) reduce the applicable margin for Eurodollar loans from 2.0% - 3.0% to 1.5% - 2.5% , depending on level of facility usage, (iii) amend the covenant limiting payment of dividends and distributions on equity to increase the Company’s ability to make dividends and distributions on its equity interests and (iv) amend certain other provisions, in each case as set forth therein. The obligations of the Company under the credit agreement are guaranteed by the Company’s material domestic 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% 0.50% 1.50% 0.375% Greater than or equal to 25% but less than 50% 0.75% 1.75% 0.375% Greater than or equal to 50% but less than 75% 1.00% 2.00% 0.500% Greater than or equal to 75% but less than 90% 1.25% 2.25% 0.500% Greater than or equal to 90% 1.50% 2.50% 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 premiums and debt issuance costs and is net of cash and cash equivalents, EBITDA will be 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. As of June 30, 2018 , the ratio of Total Debt to EBITDA was 2.53 to 1.00 and the Current Ratio was 1.49 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. The credit agreement is subject to customary events of default, including in connection with a change in control. If an event of default occurs and is continuing, the lenders may elect to accelerate amounts due under the credit agreement (except in the case of a bankruptcy event of default, in which case such amounts will automatically become due and payable). Redemptions of 7.50% 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. Upon the redemptions, the Company paid $336.9 million , which included redemption premiums of $6.0 million as well as accrued and unpaid interest of $10.9 million from the last interest payment date up to, but not including, the redemption date. 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 paid to redeem the notes and non-cash charges of $2.7 million attributable to the write-off of unamortized premium and debt issuance costs. Redemption of Other Long-Term Debt On May 3, 2018, the Company redeemed the remaining $4.4 million outstanding principal amount of its 4.375% Convertible Senior Notes due 2028 at a price equal to 100% of par. Upon redemption, the Company paid $4.5 million , which included accrued and unpaid interest of $0.1 million from the last interest payment date up to, but not including, the redemption date.

Commitments And Contingencies

Commitments And Contingencies	6 Months Ended
	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	7. 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, natural gas regulation, tax increases, 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, 2018
Preferred Stock [Abstract]
Preferred Stock	8. Preferred Stock and Warrants 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 8.875% redeemable preferred stock, par value $0.01 per share (the “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 “GSO Funds”). 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 all or 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 September 15, 2018 100 % 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 Preferred Stock outstanding is not mandatorily redeemable, but can be redeemed at the Company’s option and, in certain circumstances, at the option of the holders of the 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. In the first quarter of 2018, the Company redeemed 50,000 shares of Preferred Stock, representing 20% of the issued and outstanding Preferred Stock. Upon redemption, the Company paid $50.5 million , which consisted of $1,000.00 per share of Preferred Stock redeemed, plus accrued and unpaid dividends, with a portion of the proceeds from the divestitures of oil and gas properties. See “Note 3. Acquisitions and Divestitures of Oil and Gas Properties” for information regarding divestitures. In addition, at any time on or prior to August 10, 2020, the Company may redeem all or part of the Preferred Stock in cash at a redemption premium of 104.4375% , plus accrued and unpaid dividends and the present value on the redemption date of all quarterly dividends that would be payable from the redemption date through August 10, 2020. After August 10, 2020, the Company may redeem all or part of the Preferred Stock in cash at redemption premiums, as presented in the table below, plus accrued but unpaid dividends. Period Percentage After August 10, 2020 but on or prior to August 10, 2021 104.4375 % After August 10, 2021 but on or prior to August 10, 2022 102.21875 % After August 10, 2022 100 % The holders of the Preferred Stock have the option to cause the Company to redeem the Preferred Stock under the following conditions: • Upon the Company’s failure to pay a quarterly dividend within three months of the applicable payment date; • On or after August 10, 2024, if the Preferred Shares remain outstanding; or • Upon the occurrence of certain changes of control. For the first two conditions described above, the Company has the option to settle any such redemption in cash or shares of its common stock and the holders of the Preferred Stock may elect to revoke or reduce the redemption if the Company elects to settle in shares of common stock. The Preferred Stock are non-voting shares except as required by the Company’s articles of incorporation or bylaws. However, so long as the GSO Funds beneficially own more than 50% of the Preferred Stock, the consent of the holders of the Preferred Stock will be required prior to issuing stock senior to or on parity with the Preferred Stock, incurring indebtedness subject to a leverage ratio, agreeing to certain restrictions on dividends on, or redemption of, the Preferred Stock and declaring or paying dividends on the Company’s common stock in excess of $15.0 million per year subject to a leverage ratio. Additionally, if the Company does not redeem the Preferred Stock before August 10, 2024, in connection with a change of control or failure to pay a quarterly dividend within three months of the applicable payment date, the holders of the Preferred Stock are entitled to additional rights including: • Increasing the dividend rate to 12.0% per annum until August 10, 2024 and thereafter to the greater of 12.0% per annum and the one-month LIBOR plus 10.0% ; • Electing up to two directors to the Company’s Board of Directors; and • Requiring approval by the holders of the Preferred Stock to incur indebtedness subject to a leverage ratio, declaring or paying dividends on the Company’s common stock in excess of $15.0 million per year or issuing equity of the Company’s subsidiaries to third parties. The Preferred Stock is presented as temporary equity in the consolidated balance sheets with the issuance date fair value accreted to the redemption value using the effective interest method. The table below summarizes changes in the carrying amount of Preferred Stock for the six months ended June 30, 2018 : June 30, 2018 (In thousands) Preferred Stock, beginning of period $214,262 Redemption of preferred stock (42,897 ) Accretion on Preferred Stock 1,493 Preferred Stock, end of period $172,858 Preferred Stock Dividends, Accretion, and Loss on Redemption Dividends, accretion, and loss on redemption of preferred stock are presented in the consolidated statements of income as a reduction of net income to compute net income attributable to common shareholders. For the three months ended June 30, 2018 , the Company declared and paid $4.5 million of cash dividends to the holders of record of the Preferred Stock on June 15, 2018. For the six months ended June 30, 2018 , the Company declared and paid $9.3 million of cash dividends to the holders of the Preferred Stock on June 15, 2018 and March 15, 2018. For the three and six months ended June 30, 2018 , the Company recorded accretion on Preferred Stock of $0.7 million and $1.5 million , respectively. As a result of the redemption described above, the Company recorded a loss on redemption of preferred stock of $7.1 million , which included $0.1 million of direct costs incurred as a result of the redemption and a non-cash charge of $7.0 million attributable to the difference between $50.0 million , which was the consideration transferred to the holders of the Preferred Stock excluding accrued and unpaid dividends, and $42.9 million , which was 20% of the carrying value of the Preferred Stock on the date of redemption.

Shareholders' Equity and Stock

Shareholders' Equity and Stock Incentive Plans	6 Months Ended
	Jun. 30, 2018
Shareholders' Equity and Stock Incentive Plans [Abstract]
Shareholders' Equity and Share-based Payments	9. Stock-Based Compensation Equity-Based Incentive Awards Plans The Company grants equity-based incentive awards under the 2017 Incentive Plan of Carrizo Oil & Gas, Inc. (the “2017 Incentive Plan”) and the Carrizo Oil & Gas, Inc. Cash-Settled Stock Appreciation Rights Plan (“Cash SAR Plan”). The 2017 Incentive Plan replaced the Incentive Plan of Carrizo Oil & Gas, Inc., as amended and restated effective May 15, 2014 (the “Prior Incentive Plan”) and, from the effective date of the 2017 Incentive Plan, no further awards may be granted under the Prior Incentive Plan. However, awards previously granted under the Prior Incentive Plan will remain outstanding in accordance with their terms. Under the 2017 Incentive Plan, the Company can grant restricted stock awards and units, stock appreciation rights that can be settled in shares of common stock or cash at the option of the Company, performance shares, stock options, and cash awards to employees, independent contractors, and non-employee directors. Under the Cash SAR Plan, the Company can grant stock appreciation rights that may only be settled in cash (“Cash SARs”) to employees and independent contractors. The 2017 Incentive Plan provides that up to 2,675,000 shares of the Company’s common stock, plus the shares remaining available for awards under the Prior Incentive Plan at the effective date of the 2017 Incentive Plan, may be issued (the “Maximum Share Limit”). Each restricted stock award, restricted stock unit, or performance share granted under the 2017 Incentive Plan counts as 1.35 shares against the Maximum Share Limit. Each stock option and stock appreciation right to be settled in shares of common stock (“Stock SAR”) granted under the 2017 Incentive Plan counts as 1.00 share against the Maximum Share Limit. Each stock appreciation right to be settled in shares of common stock or cash (“Incentive SAR”) granted under the 2017 Incentive Plan counts as 1.00 share against the Maximum Share Limit up to the date the Company, if it so chooses, affirmatively elects to settle the stock appreciation right in cash. Each stock appreciation right to be settled in cash (“Incentive Cash SAR”) granted under the 2017 Incentive Plan or Cash SAR does not count against the Maximum Share Limit. As of June 30, 2018 , there were 326,774 common shares remaining available for grant under the 2017 Incentive Plan. Restricted Stock Awards and Units As of June 30, 2018 , unrecognized compensation costs related to unvested restricted stock awards and units was $30.5 million and will be recognized over a weighted average period of 2.2 years. The table below summarizes restricted stock award and unit activity for the six months ended June 30, 2018 : Restricted Stock Awards and Units Weighted Average Grant Date Fair Value Unvested restricted stock awards and units, beginning of period 1,482,655 $28.07 Granted 1,348,415 $14.68 Vested (608,904 ) $31.43 Forfeited (10,993 ) $19.17 Unvested restricted stock awards and units, end of period 2,211,173 $19.02 During the six months ended June 30, 2018 , the Company granted 1,348,415 restricted stock awards and units primarily consisting of 1,343,412 restricted stock units to employees and independent contractors as part of its annual grant of long-term equity incentive awards during the first quarter of 2018. These restricted stock units had a grant date fair value of $19.7 million and will vest ratably over a three -year period. Stock Appreciation Rights (“SARs”) As of June 30, 2018 , all outstanding SARs are either Cash SARs or Incentive Cash SARs and will be settled in cash. The liability for SARs as of June 30, 2018 was $8.7 million , all of which was classified as “Other current liabilities,” in the consolidated balance sheets. As of December 31, 2017 , the liability for SARs was $4.4 million , all of which was classified as “Other liabilities” in the consolidated balance sheets. Unrecognized compensation costs related to unvested SARs was $11.3 million as of June 30, 2018 , and will be recognized over a weighted average period of 2.6 years. The table below summarizes the activity for SARs for the six months ended June 30, 2018 : SARs Weighted Average Exercise Prices Weighted Average Remaining Life (In years) Aggregate Intrinsic Value (In millions) Aggregate Intrinsic Value of Exercises (In millions) Outstanding, beginning of period 714,238 $27.12 Granted 616,686 $14.67 Exercised — $— $— Forfeited — $— Expired — $— Outstanding, end of period 1,330,924 $21.35 4.8 $9.1 Vested, end of period 543,018 $27.18 Vested and exercisable, end of period 543,018 $27.18 3.04 $0.5 During the six months ended June 30, 2018 , the Company granted 616,686 Incentive Cash SARs to certain employees and independent contractors, all of which occurred in the first quarter of 2018 as part of the Company’s annual grant of long-term equity incentive awards. These Incentive Cash SARs will vest ratably over a three -year period and expire approximately seven years from the grant date. The grant date fair value of the Incentive Cash SARs, calculated using the Black-Scholes-Merton option pricing model, was $4.9 million . The following table summarizes the assumptions used to calculate the grant date fair value of the Incentive Cash SARs granted during the six months ended June 30, 2018 : Grant Date Fair Value Assumptions Expected term (in years) 6.0 Expected volatility 54.3 % Risk-free interest rate 2.8 % Dividend yield — % Performance Shares As of June 30, 2018 , unrecognized compensation costs related to unvested performance shares was $2.9 million and will be recognized over a weighted average period of 2.2 years. The table below summarizes performance share activity for the six months ended June 30, 2018 : Target Performance Shares (1) Weighted Average Grant Date Fair Value Unvested performance shares, beginning of period 144,955 $47.14 Granted 93,771 $19.09 Vested at end of performance period (49,458 ) $65.51 Did not vest at end of performance period (7,059 ) $65.51 Forfeited — $— Unvested performance shares, end of period 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. During the six months ended June 30, 2018 , the Company granted 93,771 target performance shares to certain employees and independent contractors, all of which occurred in the first quarter of 2018 as part of the Company’s annual grant of long-term equity incentive awards. Each performance share represents the right to receive one share of common stock, however, the number of performance shares that will 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. Also during the six months ended June 30, 2018 , the Company vested 49,458 performance shares that were granted in 2015. As a result of the Company’s final TSR ranking during the performance period, a multiplier of 88% was applied to the 56,517 target performance shares that were granted in 2015, resulting in 7,059 performance shares that did not vest. The grant date fair value of the performance shares, calculated using a Monte Carlo simulation, was $1.8 million . The following table summarizes the assumptions used to calculate the grant date fair value of the performance shares granted during the six months ended June 30, 2018 : Grant Date Fair Value Assumptions Number of simulations 500,000 Expected term (in years) 3.0 Expected volatility 61.5 % Risk-free interest rate 2.4 % Dividend yield — % Stock-Based Compensation Expense, Net Stock-based compensation expense associated with restricted stock awards and units, SARs and performance shares is reflected as “General and administrative expense, 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, 2018 and 2017 : Three Months Ended Six Months Ended 2018 2017 2018 2017 (In thousands) Restricted stock awards and units $4,720 $5,024 $9,804 $10,873 SARs 5,788 (3,783 ) 4,373 (7,469 ) Performance shares 406 574 963 1,280 10,914 1,815 15,140 4,684 Less: amounts capitalized to oil and gas properties (3,708 ) (233 ) (4,416 ) (1,088 ) Total stock-based compensation expense, net $7,206 $1,582 $10,724 $3,596

Derivative Instruments

Derivative Instruments	6 Months Ended
	Jun. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	10. Derivative Instruments Commodity Derivative Instruments The Company uses commodity derivative instruments to reduce its exposure to commodity price volatility for a portion of its forecasted production and thereby achieve a more predictable level of cash flows to support the Company’s capital expenditure program and fixed costs. The Company does not enter into derivative instruments for speculative or trading purposes. The Company’s commodity derivative instruments consist of price swaps, three-way collars, basis swaps, and purchased and sold call options, which are described below. Price Swaps: The Company receives a fixed price and pays an index price to the counterparty over specified periods for contracted volumes. Three-Way Collars: A three-way collar is a combination of options including a purchased put option (fixed floor price), a sold call option (fixed ceiling price) and a sold put option (fixed sub-floor price). These contracts offer a higher fixed ceiling price relative to a costless collar but limit the Company’s protection from decreases in commodity prices below the fixed floor price. At settlement, if the published index price is between the fixed floor price and the fixed sub-floor price or is above the fixed ceiling price, the Company receives the fixed floor price or pays the index price, respectively. If the index price is below the fixed sub-floor price, the Company receives the index price plus the difference between the fixed floor price and the fixed sub-floor price. If the index price is between the fixed floor price and fixed ceiling price, no payments are due from either party. The Company has incurred premiums on certain of these contracts in order to obtain a higher floor price and/or ceiling price. Basis Swaps: Basis swaps fix the price differential between a published index price and the applicable local index price under which our production is sold. For the Company’s Permian oil production, the basis swaps fix the price differential between the Midland WTI price and the Cushing WTI price and for the Company’s Eagle Ford oil production, the basis swaps fix the price differential between the LLS price and the Cushing WTI price. Sold Call Options : These contracts give the counterparty the right, but not the obligation, to buy contracted volumes from the Company over specified periods and prices in the future. At settlement, if the index price exceeds the fixed price of the call option, the Company pays the counterparty the excess. If the index price settles below the fixed price of the call option, no payment is due from either party. These contracts require the counterparty to pay premiums to the Company that represent the fair value of the call option as of the date of sale. All of the Company’s natural gas sold call options were executed contemporaneously with certain crude oil price swaps to increase the fixed price on those crude oil price swaps. Those certain crude oil price swaps settled prior to 2018 . Purchased Call Options : These contracts give the Company the right, but not the obligation, to buy contracted volumes from the counterparty over specified periods and prices in the future. At settlement, if the index price exceeds the fixed price of the call option, the counterparty pays the Company the excess. If the index price settles below the fixed price of the call option, no payment is due from either party. These contracts require the Company to pay premiums to the counterparty that represent the fair value of the call option as of the date of purchase. All of the Company’s purchased crude oil call options were executed contemporaneously with sold crude oil call options to increase the fixed price on a portion of the existing sold crude oil call options and therefore are presented on a net basis as “Net Sold Call Options” in the table below. Premiums : In order to increase the fixed price on a portion of the Company’s existing sold call options, the Company incurred premiums on its purchased call options. Additionally, in order to obtain a higher floor price and/or ceiling price, the Company incurred premiums on certain of its three-way collars. Payment of these premiums are deferred until the applicable contracts settle on a monthly basis throughout 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. The following table sets forth a summary of the Company’s outstanding crude oil derivative positions as of June 30, 2018 at weighted average contract prices: Period Type of Contract Index Volumes (Bbls/d) Fixed Price ($/Bbl) Sub-Floor Price ($/Bbl) Floor Price ($/Bbl) Ceiling Price ($/Bbl) 2018 Q3-Q4 Price Swaps NYMEX WTI 6,000 $49.55 $— $— $— Q3-Q4 Three-Way Collars NYMEX WTI 24,000 — 39.38 49.06 60.14 Q3-Q4 Basis Swaps LLS-Cushing WTI (1) 18,000 5.11 — — — Q3-Q4 Basis Swaps Midland WTI-Cushing WTI (2) 6,000 (0.10 ) — — — Q3-Q4 Net Sold Call Options NYMEX WTI 3,388 — — — 71.33 2019 Q1-Q4 Three-Way Collars NYMEX WTI 15,000 — 41.00 49.72 62.48 Q1-Q2 Basis Swaps Midland WTI-Cushing WTI (2) 3,000 (3.83 ) — — — Q3 Basis Swaps Midland WTI-Cushing WTI (2) 3,500 (4.18 ) — — — Q4 Basis Swaps Midland WTI-Cushing WTI (2) 6,000 (3.71 ) — — — Q1-Q4 Net Sold Call Options NYMEX WTI 3,875 — — — 73.66 2020 Q1-Q4 Net Sold Call Options NYMEX WTI 4,575 — — — 75.98 (1) The index price paid under these basis swaps is LLS and the index price received is Cushing WTI plus the fixed price differential. (2) The index price paid under these basis swaps is Midland WTI and the index price received is Cushing WTI less the fixed price differential. The following table sets forth a summary of the Company’s outstanding NGL derivative positions as of June 30, 2018 at weighted average contract prices: Period Type of Contract Index Volumes (Bbls/d) Fixed Price ($/Bbl) 2018 Q3-Q4 Price Swaps Ethane - OPIS Mont Belvieu Non-TET 2,200 $12.01 Q3-Q4 Price Swaps Propane - OPIS Mont Belvieu Non-TET 1,500 34.23 Q3-Q4 Price Swaps Butane - OPIS Mont Belvieu Non-TET 200 38.85 Q3-Q4 Price Swaps Isobutane - OPIS Mont Belvieu Non-TET 600 38.98 Q3-Q4 Price Swaps Natural Gasoline - OPIS Mont Belvieu Non-TET 600 55.23 The following table sets forth a summary of the Company’s outstanding natural gas derivative positions as of June 30, 2018 at weighted average contract prices: Period Type of Contract Index Volumes (MMBtu/d) Fixed Price ($/MMBtu) Ceiling Price ($/MMBtu) 2018 Q3-Q4 Price Swaps NYMEX HH 25,000 $3.01 $— Q3-Q4 Sold Call Options NYMEX HH 33,000 — 3.25 2019 Q1-Q4 Sold Call Options NYMEX HH 33,000 — 3.25 2020 Q1-Q4 Sold Call Options NYMEX HH 33,000 — 3.50 The Company typically has numerous hedge positions that span several time periods and often result in both commodity derivative asset and liability positions held with that counterparty. The Company nets its commodity derivative instrument fair values executed with the same counterparty, along with deferred premium obligations, to a single asset or liability pursuant to ISDA master agreements, 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 where the Company’s net liability position exceeds the Company’s unsecured credit limit with the Non-Lender Counterparty to be novated to a 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. Contingent Consideration Arrangements In connection with the ExL Acquisition and in each of the divestitures of the Company’s assets in the Niobrara in the first quarter of 2018 and the Marcellus and Utica in the fourth quarter of 2017, the Company agreed to contingent consideration arrangements that could allow the Company to receive or be required to pay certain amounts if commodity prices are above specific thresholds, which are summarized in the table below. See “Note 3. Acquisitions and Divestitures of Oil and Gas Properties” included in this Quarterly Report on Form 10-Q as well as “Note 3. Acquisitions and Divestitures of Oil and Gas Properties” included in the 2017 Annual Report for details of the ExL Acquisition and each of the divestitures discussed above. Contingent Receipt (Payment) - Annual Contingent Receipt (Payment) - Aggregate Limit Contingent Consideration Arrangements Years Threshold (1) (In thousands) Contingent ExL Consideration 2018 $50.00 ($50,000 ) 2019 50.00 (50,000 ) 2020 50.00 (50,000 ) 2021 50.00 (50,000 ) ($125,000 ) Contingent Niobrara Consideration 2018 $55.00 $5,000 2019 55.00 5,000 2020 60.00 5,000 — Contingent Marcellus Consideration 2018 $3.13 $3,000 2019 3.18 3,000 2020 3.30 3,000 $7,500 Contingent Utica Consideration 2018 $50.00 $5,000 2019 53.00 5,000 2020 56.00 5,000 — (1) The price used to determine whether the specific threshold for each year has been met is the average daily closing spot price of a barrel of West Texas Intermediate crude oil as measured by the U.S. Energy Information Administration for the Contingent ExL Consideration, Contingent Niobrara Consideration, and Contingent Utica Consideration and the average settlement price of a 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. for the Contingent Marcellus Consideration. Derivative Assets and Liabilities All commodity derivative instruments are recorded in the consolidated balance sheets as either an asset or liability measured at fair value. The deferred premium obligations associated with the Company’s commodity derivative instruments are recorded in the period in which they are incurred and are netted with the commodity derivative instrument fair value asset or liability pursuant to the netting arrangements described above. Each of the contingent consideration arrangements discussed above were determined to be embedded derivatives and are recorded in the consolidated balance sheets as either an asset or liability measured at fair value at the acquisition or divestiture date, as well as each subsequent balance sheet date. The combined derivative instrument fair value assets and liabilities, including deferred premium obligations, recorded in the consolidated balance sheets as of June 30, 2018 and December 31, 2017 are summarized below: June 30, 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 $32,422 ($31,259 ) $1,163 Contingent Niobrara Consideration 4,820 — 4,820 Contingent Marcellus Consideration 130 — 130 Contingent Utica Consideration 4,815 — 4,815 Derivative assets $42,187 ($31,259 ) $10,928 Commodity derivative instruments 13,418 (13,418 ) — Contingent Niobrara Consideration 5,150 — 5,150 Contingent Marcellus Consideration 1,400 — 1,400 Contingent Utica Consideration 5,730 — 5,730 Other assets $25,698 ($13,418 ) $12,280 Commodity derivative instruments ($118,953 ) $21,813 ($97,140 ) Deferred premium obligations (9,446 ) 9,446 — Contingent ExL Consideration (48,380 ) — (48,380 ) Derivative liabilities-current ($176,779 ) $31,259 ($145,520 ) Commodity derivative instruments (40,006 ) 5,748 (34,258 ) Deferred premium obligations (7,670 ) 7,670 — Contingent ExL Consideration (53,675 ) — (53,675 ) Derivative liabilities-non current ($101,351 ) $13,418 ($87,933 ) December 31, 2017 Gross Amounts Recognized Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts Presented in the Consolidated Balance Sheets (In thousands) Commodity derivative instruments $4,869 ($4,869 ) $— Derivative assets $4,869 ($4,869 ) $— Commodity derivative instruments 9,505 (9,505 ) — Contingent Niobrara Consideration — — — Contingent Marcellus Consideration 2,205 — 2,205 Contingent Utica Consideration 7,985 — 7,985 Other assets $19,695 ($9,505 ) $10,190 Commodity derivative instruments ($52,671 ) ($4,450 ) ($57,121 ) Deferred premium obligations (9,319 ) 9,319 — Derivative liabilities-current ($61,990 ) $4,869 ($57,121 ) Commodity derivative instruments (24,609 ) (2,098 ) (26,707 ) Deferred premium obligations (11,603 ) 11,603 — Contingent ExL Consideration (85,625 ) — (85,625 ) Derivative liabilities-non current ($121,837 ) $9,505 ($112,332 ) See “Note 11. Fair Value Measurements” for additional information regarding the fair value of the Company’s derivative instruments. (Gain) Loss on Derivatives, Net The Company has elected not to meet the criteria to qualify its commodity derivative instruments for hedge accounting treatment. Therefore, all gains and losses as a result of changes in the fair value of the Company’s commodity derivative instruments, as well as its contingent consideration arrangements, are recognized as “(Gain) loss on derivatives, net” in the consolidated statements of income in the period in which the changes occur. All deferred premium obligations associated with the Company’s commodity derivative instruments are recognized in “(Gain) loss on derivatives, net” in the consolidated statements of income in the period in which the deferred premium obligations are incurred. The effects of commodity derivative instruments, deferred premium obligations and contingent consideration arrangements in the consolidated statements of income for the three and six months ended June 30, 2018 and 2017 are summarized below: Three Months Ended Six Months Ended 2018 2017 2018 2017 (In thousands) (Gain) Loss on Derivatives, Net Crude oil derivatives $53,437 ($29,736 ) $82,948 ($48,163 ) NGL derivatives 6,564 — 4,799 — Natural gas derivatives 153 (3,883 ) (2,892 ) (10,719 ) Deferred premium obligations — 7,554 — 7,501 Contingent ExL Consideration 10,600 — 16,430 — Contingent Niobrara Consideration (1,705 ) — (2,090 ) — Contingent Marcellus Consideration 205 — 675 — Contingent Utica Consideration (1,540 ) — (2,560 ) — (Gain) Loss on Derivatives, Net $67,714 ($26,065 ) $97,310 ($51,381 ) Cash Received (Paid) for Derivative Settlements, Net Cash flows are impacted to the extent that settlements of commodity derivatives, including deferred premium obligations, and settlements of contingent consideration arrangements result in cash receipts or payments during the period and are presented as “Cash received (paid) for derivative settlements, net” in the consolidated statements of cash flows. Cash payments made to settle contingent consideration liabilities are classified as cash flows from financing activities up to the divestiture or acquisition date fair value with any excess classified as cash flows from operating activities. For the three and six months ended June 30, 2018 and 2017 , the Company did not receive or pay cash for the contingent consideration arrangements. The net cash received (paid) for settlements of commodity derivatives and deferred premium obligations in the consolidated statements of cash flows for the three and six months ended June 30, 2018 and 2017 are summarized below: Three Months Ended Six Months Ended 2018 2017 2018 2017 Cash Flows from Operating Activities (In thousands) Cash Received (Paid) for Derivative Settlements, Net Crude oil derivatives ($21,210 ) $409 ($33,333 ) $3,441 NGL derivatives (756 ) — (1,188 ) — Natural gas derivatives 488 (104 ) 540 (1,253 ) Deferred premium obligations (2,605 ) (566 ) (4,467 ) (930 ) Cash Received (Paid) for Derivative Settlements, Net ($24,083 ) ($261 ) ($38,448 ) $1,258

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	11. 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 commodity derivative instrument and contingent consideration arrangement assets and liabilities measured at fair value on a recurring basis as of June 30, 2018 and December 31, 2017 : June 30, 2018 Level 1 Level 2 Level 3 (In thousands) Assets Commodity derivative instruments $— $1,163 $— Contingent Niobrara Consideration — — 9,970 Contingent Marcellus Consideration — — 1,530 Contingent Utica Consideration — — 10,545 Liabilities Commodity derivative instruments $— ($131,398 ) $— Contingent ExL Consideration — — (102,055 ) December 31, 2017 Level 1 Level 2 Level 3 (In thousands) Assets Commodity derivative instruments $— $— $— Contingent Niobrara Consideration — — — Contingent Marcellus Consideration — — 2,205 Contingent Utica Consideration — — 7,985 Liabilities Commodity derivative instruments $— ($83,828 ) $— Contingent ExL Consideration — — (85,625 ) The commodity derivative and contingent consideration arrangement 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. The Company typically has numerous hedge positions that span several time periods and often result in both commodity derivative asset and liability positions held with that counterparty. Deferred premium obligations are netted with the commodity derivative asset and liability positions, which are all offset to a single asset or liability, at the end of each reporting period. The Company nets the fair values of its assets and liabilities associated with commodity derivative instruments executed with the same counterparty, along with deferred premium obligations, pursuant to ISDA master agreements, which provide for net settlement over the term of the contract and in the event of default or termination of the contract. The Company had no transfers into Level 1 and no transfers into or out of Level 2 for the six months ended June 30, 2018 and 2017 . 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, discount rates and volatility factors. As some of these assumptions are not observable throughout the full term of the contingent consideration arrangements, the contingent consideration arrangements were designated as Level 3 within the valuation hierarchy. The Company reviewed the valuations, including the related inputs, and analyzed changes in fair value measurements between periods. The following table presents the reconciliation of changes in the fair values of the contingent consideration arrangements, which were designated as Level 3 within the valuation hierarchy, for the six months ended June 30, 2018 : Contingent Consideration Arrangements Assets Liability For the Six Months Ended June 30, 2018 (In thousands) Beginning of period $10,190 ($85,625 ) Recognition of divestiture date fair value 7,880 — Gain (loss) on changes in fair value, net (1) 3,975 (16,430 ) Transfers into (out of) Level 3 — — End of period $22,045 ($102,055 ) (1) Included in “(Gain) loss on derivatives, net” in the consolidated statements of income. See “Note 10. Derivative Instruments” for additional information regarding the contingent consideration arrangements. Assets and Liabilities Measured at Fair Value on a Non-Recurring Basis 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 inputs. 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. 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 carrying amounts of the Company’s senior notes and other long-term debt, which are designated as Level 1 under the fair value hierarchy, net of unamortized premiums and debt issuance costs, with the fair values measured using quoted secondary market trading prices. June 30, 2018 December 31, 2017 Carrying Amount Fair Value Carrying Amount Fair Value (In thousands) 7.50% Senior Notes due 2020 $129,044 $130,325 $446,087 $459,518 6.25% Senior Notes due 2023 642,446 656,500 641,792 674,375 8.25% Senior Notes due 2025 245,817 266,250 245,605 274,375 Other long-term debt due 2028 — — 4,425 4,445

Condensed Consolidating Financi

Condensed Consolidating Financial Information	6 Months Ended
	Jun. 30, 2018
Condensed Consolidating Financial Information [Abstract]
Condensed Consolidating Financial Information	12. Condensed Consolidating Financial Information The rules of the SEC require that condensed consolidating financial information be provided for a subsidiary that has guaranteed the debt of a registrant issued in a public offering, where the guarantee is full, unconditional and joint and several and where the voting interest of the subsidiary is 100% owned by the registrant. The Company is, therefore, presenting condensed consolidating financial information on a parent company, combined guarantor subsidiaries, combined non-guarantor subsidiaries and consolidated basis and should be read in conjunction with the consolidated financial statements. The financial information may not necessarily be indicative of results of operations, cash flows, or financial position had such guarantor subsidiaries operated as independent entities. CARRIZO OIL & GAS, INC. CONDENSED CONSOLIDATING BALANCE SHEETS (In thousands) (Unaudited) June 30, 2018 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Assets Total current assets $3,128,244 $120,425 $— ($3,116,164 ) $132,505 Total property and equipment, net 6,445 2,562,799 3,028 (3,847 ) 2,568,425 Investment in subsidiaries (743,363 ) — — 743,363 — Other assets 8,630 12,279 — — 20,909 Total Assets $2,399,956 $2,695,503 $3,028 ($2,376,648 ) $2,721,839 Liabilities and Shareholders’ Equity Current liabilities $257,137 $3,362,551 $3,028 ($3,119,185 ) $503,531 Long-term liabilities 1,526,788 76,315 — 15,879 1,618,982 Preferred stock 172,858 — — — 172,858 Total shareholders’ equity 443,173 (743,363 ) — 726,658 426,468 Total Liabilities and Shareholders’ Equity $2,399,956 $2,695,503 $3,028 ($2,376,648 ) $2,721,839 December 31, 2017 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Assets Total current assets $3,441,633 $105,533 $— ($3,424,288 ) $122,878 Total property and equipment, net 5,953 2,630,707 3,028 (3,878 ) 2,635,810 Investment in subsidiaries (999,793 ) — — 999,793 — Other assets 9,270 10,346 — — 19,616 Total Assets $2,457,063 $2,746,586 $3,028 ($2,428,373 ) $2,778,304 Liabilities and Shareholders’ Equity Current liabilities $165,701 $3,631,401 $3,028 ($3,427,308 ) $372,822 Long-term liabilities 1,689,466 114,978 — 15,879 1,820,323 Preferred stock 214,262 — — — 214,262 Total shareholders’ equity 387,634 (999,793 ) — 983,056 370,897 Total Liabilities and Shareholders’ Equity $2,457,063 $2,746,586 $3,028 ($2,428,373 ) $2,778,304 CARRIZO OIL & GAS, INC. CONDENSED CONSOLIDATING STATEMENTS OF INCOME (In thousands) (Unaudited) Three Months Ended June 30, 2018 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Total revenues $19 $263,954 $— $— $263,973 Total costs and expenses 106,335 121,869 — (23 ) 228,181 Income (loss) before income taxes (106,316 ) 142,085 — 23 35,792 Income tax expense — (483 ) — — (483 ) Equity in income of subsidiaries 141,602 — — (141,602 ) — Net income $35,286 $141,602 $— ($141,579 ) $35,309 Dividends on preferred stock (4,474 ) — — — (4,474 ) Accretion on preferred stock (740 ) — — — (740 ) Loss on redemption of preferred stock — — — — — Net income attributable to common shareholders $30,072 $141,602 $— ($141,579 ) $30,095 Three Months Ended June 30, 2017 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Total revenues $174 $166,309 $— $— $166,483 Total costs and expenses 7,731 102,415 — 31 110,177 Income (loss) before income taxes (7,557 ) 63,894 — (31 ) 56,306 Income tax expense — — — — — Equity in income of subsidiaries 63,894 — — (63,894 ) — Net income $56,337 $63,894 $— ($63,925 ) $56,306 Dividends on preferred stock — — — — — Accretion on preferred stock — — — — — Loss on redemption of preferred stock — — — — — Net income attributable to common shareholders $56,337 $63,894 $— ($63,925 ) $56,306 CARRIZO OIL & GAS, INC. CONDENSED CONSOLIDATING STATEMENTS OF INCOME (In thousands) (Unaudited) Six Months Ended June 30, 2018 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Total revenues $39 $489,214 $— $— $489,253 Total costs and expenses 193,700 231,982 — (32 ) 425,650 Income (loss) before income taxes (193,661 ) 257,232 — 32 63,603 Income tax expense — (802 ) — — (802 ) Equity in income of subsidiaries 256,430 — — (256,430 ) — Net income $62,769 $256,430 $— ($256,398 ) $62,801 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 attributable to common shareholders $44,806 $256,430 $— ($256,398 ) $44,838 Six Months Ended June 30, 2017 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Total revenues $256 $317,582 $— $— $317,838 Total costs and expenses 26,599 194,871 — 41 221,511 Income (loss) before income taxes (26,343 ) 122,711 — (41 ) 96,327 Income tax expense — — — — — Equity in income of subsidiaries 122,711 — — (122,711 ) — Net income $96,368 $122,711 $— ($122,752 ) $96,327 Dividends on preferred stock — — — — — Accretion on preferred stock — — — — — Loss on redemption of preferred stock — — — — — Net income attributable to common shareholders $96,368 $122,711 $— ($122,752 ) $96,327 CARRIZO OIL & GAS, INC. CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS (In thousands) (Unaudited) Six Months Ended June 30, 2018 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Net cash provided by (used in) operating activities ($158,309 ) $434,181 $— $— $275,872 Net cash provided by (used in) investing activities 348,235 (84,355 ) — (349,826 ) (85,946 ) Net cash used in financing activities (197,367 ) (349,826 ) — 349,826 (197,367 ) Net decrease in cash and cash equivalents (7,441 ) — — — (7,441 ) Cash and cash equivalents, beginning of period 9,540 — — — 9,540 Cash and cash equivalents, end of period $2,099 $— $— $— $2,099 Six Months Ended June 30, 2017 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Net cash provided by (used in) operating activities ($77,501 ) $256,656 $— $— $179,155 Net cash used in investing activities (109,780 ) (364,887 ) — 108,231 (366,436 ) Net cash provided by financing activities 185,315 108,231 — (108,231 ) 185,315 Net decrease in cash and cash equivalents (1,966 ) — — — (1,966 ) Cash and cash equivalents, beginning of period 4,194 — — — 4,194 Cash and cash equivalents, end of period $2,228 $— $— $— $2,228

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	6 Months Ended
	Jun. 30, 2018
Supplemental Cash Flow Elements [Abstract]
Cash Flow, Supplemental Disclosures	13. Supplemental Cash Flow Information Supplemental cash flow disclosures and non-cash investing activities are presented below: Six Months Ended 2018 2017 (In thousands) Supplemental cash flow disclosures: Cash paid for interest, net of amounts capitalized $29,853 $39,603 Non-cash investing activities: Increase in capital expenditure payables and accruals $35,543 $48,395 Contingent consideration arrangement related to divestitures of oil and gas properties (7,880 ) —

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	14. Subsequent Events Divestiture of Non-Operated Delaware Basin Assets In July 2018, the Company closed on the divestiture of certain non-operated assets in the Delaware Basin for estimated aggregate net proceeds of $31.4 million . The proceeds from this divestiture will be recognized as a reduction of proved oil and gas properties. Hedging In August 2018, the Company entered into the following crude oil derivative positions at the weighted average contract prices summarized below: Period Type of Contract Index Volumes (Bbls/d) Fixed Price ($/Bbl) 2019 Q1 Basis Swaps Midland WTI-Cushing WTI (1) 2,500 ($6.94 ) Q2 Basis Swaps Midland WTI-Cushing WTI (1) 3,000 (6.94 ) Q3 Basis Swaps Midland WTI-Cushing WTI (1) 3,500 (6.94 ) Q4 Basis Swaps Midland WTI-Cushing WTI (1) 5,000 (4.00 ) 2020 Q1 Basis Swaps Midland WTI-Cushing WTI (1) 1,000 (1.90 ) (1) The index price paid under these basis swaps is Midland WTI and the index price received is Cushing WTI less the fixed price differential.

Summary of Significant Accoun21

Summary of Significant Accounting Policies (Policy)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
New Accounting Pronouncements	Revenue Recognition Impact of ASC 606 Adoption . Effective January 1, 2018, the Company adopted ASU No. 2014-09, Revenue From Contracts With Customers (Topic 606) (“ASC 606”) using the modified retrospective method and has applied the standard to all existing contracts. ASC 606 supersedes previous revenue recognition requirements in ASC 605 - Revenue Recognition (“ASC 605”) and includes a five-step revenue recognition model to depict the transfer of goods or services to customers in an amount that reflects the consideration in exchange for those goods or services. As a result of adopting ASC 606, the Company did not have a cumulative-effect adjustment in retained earnings. The comparative information for the three and six months ended June 30, 2017 has not been recast and continues to be reported under the accounting standards in effect for that period. Additionally, adoption of ASC 606 did not impact net income attributable to common shareholders and the Company does not expect that it will do so in future periods. The tables below summarizes the impact of adoption for the three and six months ended June 30, 2018 : Three Months Ended June 30, 2018 Under ASC 606 Under ASC 605 Increase % Increase (In thousands) Revenues Crude oil $229,798 $229,658 $140 0.1 % Natural gas liquids 21,269 20,139 1,130 5.6 % Natural gas 12,906 12,272 634 5.2 % Total revenues 263,973 262,069 1,904 0.7 % Costs and Expenses Lease operating 35,151 33,247 1,904 5.7 % Income Before Income Taxes $35,792 $35,792 $— — % Six Months Ended June 30, 2018 Under ASC 606 Under ASC 605 Increase % Increase (In thousands) Revenues Crude oil $424,717 $424,452 $265 0.1 % Natural gas liquids 38,171 36,235 1,936 5.3 % Natural gas 26,365 25,159 1,206 4.8 % Total revenues 489,253 485,846 3,407 0.7 % Costs and Expenses Lease operating 74,424 71,017 3,407 4.8 % Income Before Income Taxes $63,603 $63,603 $— — % Changes to crude oil, NGL, and natural gas revenues and lease operating expense are due to the conclusion that the Company controls the product throughout processing before transferring to the customer for certain natural gas processing arrangements. Therefore, any transportation, gathering, and processing fees incurred prior to transfer of control are included in lease operating expense. 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 our 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, 2018 and December 31, 2017 , receivables from contracts with customers were $87.1 million and $85.6 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 income. Crude oil sales. Crude oil production is primarily sold at the wellhead at an agreed upon index price, net of pricing differentials. Revenue is recognized when control transfers to the purchaser at the wellhead, net of transportation costs incurred by the purchaser. Natural gas and NGL sales. Natural gas is delivered to a midstream processing entity at the wellhead or the inlet of the midstream processing entity’s system. The midstream processing entity gathers and processes the natural gas and remits proceeds for the resulting sales of NGLs and residue gas. The Company evaluates whether it is the principal or agent in the transaction and has concluded it is the principal and the ultimate third party is the customer. Revenue is recognized on a gross basis, with gathering, processing and transportation fees presented in “Lease operating expense” in the consolidated statements of income as the Company maintains control throughout processing. Transaction Price Allocated to Remaining Performance Obligations . The Company applied the practical expedient in ASC 606 exempting the disclosure of the transaction price allocated to remaining performance obligations if the variable consideration is allocated entirely to a wholly unsatisfied performance obligation. Each unit of product typically represents a separate performance obligation, therefore, future volumes are wholly unsatisfied and disclosure of the transaction price allocated to remaining performance obligations is not required. Recently Adopted Accounting Pronouncements Business Combinations. In January 2017, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business (“ASU 2017-01”), which clarifies the definition of a business to assist entities with evaluating whether transactions should be accounted for as acquisitions (or divestitures) of assets or businesses. Effective January 1, 2018, the Company adopted ASU 2017-01 using the prospective method and will apply the clarified definition of a business to future acquisition and divestitures. Statement of Cash Flows. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (“ASU 2016-15”), which is intended to reduce diversity in practice in how certain transactions are classified in the statement of cash flows. The guidance addresses eight specific cash flow issues for which current GAAP is either unclear or does not include specific guidance. Effective January 1, 2018, the Company adopted ASU 2016-15 using the retrospective approach as prescribed by ASU 2016-15. There were no changes to the statement of cash flows as a result of adoption. Recently Issued Accounting Pronouncements Leases. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (“ASU 2016-02”), which significantly changes accounting for leases by requiring that lessees recognize a right-of-use asset and a related lease liability representing the obligation to make lease payments, for virtually all lease transactions. ASU 2016-02 does not apply to leases of mineral rights to explore for or use crude oil and natural gas. Additional disclosures about an entity’s lease transactions will also be required. ASU 2016-02 defines a lease as “a contract, or part of a contract, that conveys the right to control the use of identified property, plant or equipment (an identified asset) for a period of time in exchange for consideration.” ASU 2016-02 is effective for interim and annual periods beginning after December 15, 2018 with early adoption permitted. ASU 2016-02 requires companies to recognize and measure leases at the beginning of the earliest period presented in the financial statements using a modified retrospective approach. The Company is in the process of reviewing and determining the contracts to which ASU 2016-02 applies with the assistance of a third party consultant. These include contracts such as non-cancelable leases, drilling rig contracts, pipeline gathering, transportation and gas processing agreements, and contracts for the use of vehicles and well equipment. The Company continues to review current accounting policies, controls, processes, and disclosures that will change as a result of adopting the new standard. Based upon its initial assessment, the Company expects the adoption of ASU 2016-02 will result in: (i) an increase in assets and liabilities due to the required recognition of right-of-use (“ROU”) assets and corresponding lease liabilities, (ii) increases in depreciation, depletion and amortization and interest expense, (iii) decreases in lease operating and general and administrative expense and (iv) additional disclosures, however, the full impact to the Company’s consolidated financial statements and related disclosures is still being evaluated. Currently, the Company plans to make certain elections allowing the Company not to reassess contracts that commenced prior to adoption, to continue applying its current accounting policy for land easements, and not to recognize ROU assets or lease liabilities for short-term leases. The Company plans to adopt the guidance on the effective date of January 1, 2019. As permitted by ASU No. 2018-11, Leases (Topic 842): Targeted Improvements, the Company does not expect to adjust comparative-period financial statements. Other than as disclosed above or in the Company’s 2017 Form 10-K, there are no other accounting standard updates applicable to the Company that would have a material effect on the Company’s consolidated financial statements and related disclosures that have been issued but not yet adopted by the Company as of June 30, 2018, and through the filing of this report.

Summary of Significant Accoun22

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]	The tables below summarizes the impact of adoption for the three and six months ended June 30, 2018 : Three Months Ended June 30, 2018 Under ASC 606 Under ASC 605 Increase % Increase (In thousands) Revenues Crude oil $229,798 $229,658 $140 0.1 % Natural gas liquids 21,269 20,139 1,130 5.6 % Natural gas 12,906 12,272 634 5.2 % Total revenues 263,973 262,069 1,904 0.7 % Costs and Expenses Lease operating 35,151 33,247 1,904 5.7 % Income Before Income Taxes $35,792 $35,792 $— — % Six Months Ended June 30, 2018 Under ASC 606 Under ASC 605 Increase % Increase (In thousands) Revenues Crude oil $424,717 $424,452 $265 0.1 % Natural gas liquids 38,171 36,235 1,936 5.3 % Natural gas 26,365 25,159 1,206 4.8 % Total revenues 489,253 485,846 3,407 0.7 % Costs and Expenses Lease operating 74,424 71,017 3,407 4.8 % Income Before Income Taxes $63,603 $63,603 $— — %
Schedule of Supplemental Net Income Per Common Share	Supplemental net income attributable to common shareholders per common share information is provided below: Three Months Ended Six Months Ended 2018 2017 2018 2017 (In thousands, except per share amounts) Net Income Attributable to Common Shareholders $30,095 $56,306 $44,838 $96,327 Basic weighted average common shares outstanding 82,058 65,767 81,802 65,479 Effect of dilutive instruments 1,795 141 1,438 387 Diluted weighted average common shares outstanding 83,853 65,908 83,240 65,866 Net Income Attributable to Common Shareholders Per Common Share Basic $0.37 $0.86 $0.55 $1.47 Diluted $0.36 $0.85 $0.54 $1.46
Schedule of Reconciliation of the Weighted Average Common Shares Outstanding [Table Text Block]	The table below presents the a reconciliation of the basic weighted average common shares outstanding to diluted weighted average common shares outstanding for the three and six months ended June 30, 2018 and 2017 : Three Months Ended Six Months Ended 2018 2017 2018 2017 (In thousands) Basic weighted average common shares outstanding 82,058 65,767 81,802 65,479 Dilutive unvested restricted stock awards and units 833 141 640 387 Dilutive unvested performance shares 134 — 158 — Dilutive exercisable common stock warrants 828 — 640 — Diluted weighted average common shares outstanding 83,853 65,908 83,240 65,866
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	The table below presents a summary of the common shares outstanding that were excluded from the computation of diluted net income attributable to common shareholders per common share for the three and six months ended June 30, 2018 and 2017 , as their inclusion would be anti-dilutive: Three Months Ended Six Months Ended 2018 2017 2018 2017 (In thousands) Anti-dilutive unvested restricted stock awards and units 16 101 17 16 Anti-dilutive unvested performance shares — 108 2 62 Anti-dilutive exercisable common stock warrants — — — — Total anti-dilutive 16 209 19 78

Acquisitions and Divestitures (

Acquisitions and Divestitures (Tables)	6 Months Ended
	Jun. 30, 2018
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Information [Table Text Block]	Three Months Ended Six Months Ended June 30, 2018 (In thousands) Total revenues $52,771 $96,239 Net income attributable to common shareholders $42,048 $76,851

Property And Equipment, Net (Ta

Property And Equipment, Net (Tables)	6 Months Ended
	Jun. 30, 2018
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	As of June 30, 2018 and December 31, 2017 , total property and equipment, net consisted of the following: June 30, December 31, (In thousands) Oil and gas properties, full cost method Proved properties $5,744,434 $5,615,153 Accumulated depreciation, depletion and amortization and impairments (3,784,483 ) (3,649,806 ) Proved properties, net 1,959,951 1,965,347 Unproved properties, not being amortized Unevaluated leasehold and seismic costs 539,836 612,589 Capitalized interest 58,056 47,698 Total unproved properties, not being amortized 597,892 660,287 Other property and equipment 27,223 25,625 Accumulated depreciation (16,641 ) (15,449 ) Other property and equipment, net 10,582 10,176 Total property and equipment, net $2,568,425 $2,635,810

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Schedule Of Effective Income Tax Rate Reconciliation	The Company’s income tax expense differs from the income tax expense computed by applying the U.S. federal statutory corporate income tax rate of 21% for the three and six months ended June 30, 2018 and 35% for the three and six months ended June 30, 2017, to income before income taxes as follows: Three Months Ended Six Months Ended 2018 2017 2018 2017 (In thousands) Income before income taxes $35,792 $56,306 $63,603 $96,327 Income tax expense at the statutory rate (7,517 ) (19,707 ) (13,357 ) (33,714 ) State income tax expense, net of U.S. federal income taxes (487 ) (1,017 ) (806 ) (1,727 ) Tax shortfalls from stock-based compensation expense (16 ) (164 ) (2,542 ) (2,756 ) Decrease in deferred tax assets valuation allowance 8,048 20,948 16,449 38,317 Other (511 ) (60 ) (546 ) (120 ) Income tax expense ($483 ) $— ($802 ) $—

Long-Term Debt (Tables)

Long-Term Debt (Tables)	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	Long-term debt consisted of the following as of June 30, 2018 and December 31, 2017 : June 30, December 31, (In thousands) Senior Secured Revolving Credit Facility due 2022 $485,000 $291,300 7.50% Senior Notes due 2020 130,000 450,000 Unamortized premium for 7.50% Senior Notes 139 579 Unamortized debt issuance costs for 7.50% Senior Notes (1,095 ) (4,492 ) 6.25% Senior Notes due 2023 650,000 650,000 Unamortized debt issuance costs for 6.25% Senior Notes (7,554 ) (8,208 ) 8.25% Senior Notes due 2025 250,000 250,000 Unamortized debt issuance costs for 8.25% Senior Notes (4,183 ) (4,395 ) Other long-term debt due 2028 — 4,425 Long-term debt $1,502,307 $1,629,209
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% 0.50% 1.50% 0.375% Greater than or equal to 25% but less than 50% 0.75% 1.75% 0.375% Greater than or equal to 50% but less than 75% 1.00% 2.00% 0.500% Greater than or equal to 75% but less than 90% 1.25% 2.25% 0.500% Greater than or equal to 90% 1.50% 2.50% 0.500%

Preferred Stock (Tables)

Preferred Stock (Tables)	6 Months Ended
	Jun. 30, 2018
Preferred Stock Disclosure [Abstract]
Schedule of Preferred Stock Dividends Paid in Common Stock	The Company may elect to pay all or 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 September 15, 2018 100 % 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 %
Schedule of Preferred Stock Redemption Premiums	After August 10, 2020, the Company may redeem all or part of the Preferred Stock in cash at redemption premiums, as presented in the table below, plus accrued but unpaid dividends. Period Percentage After August 10, 2020 but on or prior to August 10, 2021 104.4375 % After August 10, 2021 but on or prior to August 10, 2022 102.21875 % After August 10, 2022 100 %
Temporary Equity [Table Text Block]	The table below summarizes changes in the carrying amount of Preferred Stock for the six months ended June 30, 2018 : June 30, 2018 (In thousands) Preferred Stock, beginning of period $214,262 Redemption of preferred stock (42,897 ) Accretion on Preferred Stock 1,493 Preferred Stock, end of period $172,858

Shareholders' Equity and Stoc28

Shareholders' Equity and Stock Incentive Plans (Tables)	6 Months Ended
	Jun. 30, 2018
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 six months ended June 30, 2018 : Restricted Stock Awards and Units Weighted Average Grant Date Fair Value Unvested restricted stock awards and units, beginning of period 1,482,655 $28.07 Granted 1,348,415 $14.68 Vested (608,904 ) $31.43 Forfeited (10,993 ) $19.17 Unvested restricted stock awards and units, end of period 2,211,173 $19.02
Schedule of Stock Appreciation Rights Award Activity	The table below summarizes the activity for SARs for the six months ended June 30, 2018 : SARs Weighted Average Exercise Prices Weighted Average Remaining Life (In years) Aggregate Intrinsic Value (In millions) Aggregate Intrinsic Value of Exercises (In millions) Outstanding, beginning of period 714,238 $27.12 Granted 616,686 $14.67 Exercised — $— $— Forfeited — $— Expired — $— Outstanding, end of period 1,330,924 $21.35 4.8 $9.1 Vested, end of period 543,018 $27.18 Vested and exercisable, end of period 543,018 $27.18 3.04 $0.5
Schedule of Stock Appreciation Rights Valuation Assumptions	The following table summarizes the assumptions used to calculate the grant date fair value of the Incentive Cash SARs granted during the six months ended June 30, 2018 : Grant Date Fair Value Assumptions Expected term (in years) 6.0 Expected volatility 54.3 % Risk-free interest rate 2.8 % Dividend yield — %
Schedule of Performance Shares Award Unvested Activity	The table below summarizes performance share activity for the six months ended June 30, 2018 : Target Performance Shares (1) Weighted Average Grant Date Fair Value Unvested performance shares, beginning of period 144,955 $47.14 Granted 93,771 $19.09 Vested at end of performance period (49,458 ) $65.51 Did not vest at end of performance period (7,059 ) $65.51 Forfeited — $— Unvested performance shares, end of period 182,209 $27.01
Schedule of Performance Share Award Valuation Assumptions	following table summarizes the assumptions used to calculate the grant date fair value of the performance shares granted during the six months ended June 30, 2018 : Grant Date Fair Value Assumptions Number of simulations 500,000 Expected term (in years) 3.0 Expected volatility 61.5 % Risk-free interest rate 2.4 % Dividend yield — %
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, 2018 and 2017 : Three Months Ended Six Months Ended 2018 2017 2018 2017 (In thousands) Restricted stock awards and units $4,720 $5,024 $9,804 $10,873 SARs 5,788 (3,783 ) 4,373 (7,469 ) Performance shares 406 574 963 1,280 10,914 1,815 15,140 4,684 Less: amounts capitalized to oil and gas properties (3,708 ) (233 ) (4,416 ) (1,088 ) Total stock-based compensation expense, net $7,206 $1,582 $10,724 $3,596

Derivative Instruments (Tables)

Derivative Instruments (Tables)	6 Months Ended
	Jun. 30, 2018
Derivative [Line Items]
Schedule of Contingent Consideration	In connection with the ExL Acquisition and in each of the divestitures of the Company’s assets in the Niobrara in the first quarter of 2018 and the Marcellus and Utica in the fourth quarter of 2017, the Company agreed to contingent consideration arrangements that could allow the Company to receive or be required to pay certain amounts if commodity prices are above specific thresholds, which are summarized in the table below. See “Note 3. Acquisitions and Divestitures of Oil and Gas Properties” included in this Quarterly Report on Form 10-Q as well as “Note 3. Acquisitions and Divestitures of Oil and Gas Properties” included in the 2017 Annual Report for details of the ExL Acquisition and each of the divestitures discussed above. Contingent Receipt (Payment) - Annual Contingent Receipt (Payment) - Aggregate Limit Contingent Consideration Arrangements Years Threshold (1) (In thousands) Contingent ExL Consideration 2018 $50.00 ($50,000 ) 2019 50.00 (50,000 ) 2020 50.00 (50,000 ) 2021 50.00 (50,000 ) ($125,000 ) Contingent Niobrara Consideration 2018 $55.00 $5,000 2019 55.00 5,000 2020 60.00 5,000 — Contingent Marcellus Consideration 2018 $3.13 $3,000 2019 3.18 3,000 2020 3.30 3,000 $7,500 Contingent Utica Consideration 2018 $50.00 $5,000 2019 53.00 5,000 2020 56.00 5,000 — (1) The price used to determine whether the specific threshold for each year has been met is the average daily closing spot price of a barrel of West Texas Intermediate crude oil as measured by the U.S. Energy Information Administration for the Contingent ExL Consideration, Contingent Niobrara Consideration, and Contingent Utica Consideration and the average settlement price of a 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. for the Contingent Marcellus Consideration.
Schedule of Derivative Instrument Fair Value Assets and Liabilities	The combined derivative instrument fair value assets and liabilities, including deferred premium obligations, recorded in the consolidated balance sheets as of June 30, 2018 and December 31, 2017 are summarized below: June 30, 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 $32,422 ($31,259 ) $1,163 Contingent Niobrara Consideration 4,820 — 4,820 Contingent Marcellus Consideration 130 — 130 Contingent Utica Consideration 4,815 — 4,815 Derivative assets $42,187 ($31,259 ) $10,928 Commodity derivative instruments 13,418 (13,418 ) — Contingent Niobrara Consideration 5,150 — 5,150 Contingent Marcellus Consideration 1,400 — 1,400 Contingent Utica Consideration 5,730 — 5,730 Other assets $25,698 ($13,418 ) $12,280 Commodity derivative instruments ($118,953 ) $21,813 ($97,140 ) Deferred premium obligations (9,446 ) 9,446 — Contingent ExL Consideration (48,380 ) — (48,380 ) Derivative liabilities-current ($176,779 ) $31,259 ($145,520 ) Commodity derivative instruments (40,006 ) 5,748 (34,258 ) Deferred premium obligations (7,670 ) 7,670 — Contingent ExL Consideration (53,675 ) — (53,675 ) Derivative liabilities-non current ($101,351 ) $13,418 ($87,933 ) December 31, 2017 Gross Amounts Recognized Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts Presented in the Consolidated Balance Sheets (In thousands) Commodity derivative instruments $4,869 ($4,869 ) $— Derivative assets $4,869 ($4,869 ) $— Commodity derivative instruments 9,505 (9,505 ) — Contingent Niobrara Consideration — — — Contingent Marcellus Consideration 2,205 — 2,205 Contingent Utica Consideration 7,985 — 7,985 Other assets $19,695 ($9,505 ) $10,190 Commodity derivative instruments ($52,671 ) ($4,450 ) ($57,121 ) Deferred premium obligations (9,319 ) 9,319 — Derivative liabilities-current ($61,990 ) $4,869 ($57,121 ) Commodity derivative instruments (24,609 ) (2,098 ) (26,707 ) Deferred premium obligations (11,603 ) 11,603 — Contingent ExL Consideration (85,625 ) — (85,625 ) Derivative liabilities-non current ($121,837 ) $9,505 ($112,332 )
Schedule of (Gain) Loss on Derivative Instruments	The effects of commodity derivative instruments, deferred premium obligations and contingent consideration arrangements in the consolidated statements of income for the three and six months ended June 30, 2018 and 2017 are summarized below: Three Months Ended Six Months Ended 2018 2017 2018 2017 (In thousands) (Gain) Loss on Derivatives, Net Crude oil derivatives $53,437 ($29,736 ) $82,948 ($48,163 ) NGL derivatives 6,564 — 4,799 — Natural gas derivatives 153 (3,883 ) (2,892 ) (10,719 ) Deferred premium obligations — 7,554 — 7,501 Contingent ExL Consideration 10,600 — 16,430 — Contingent Niobrara Consideration (1,705 ) — (2,090 ) — Contingent Marcellus Consideration 205 — 675 — Contingent Utica Consideration (1,540 ) — (2,560 ) — (Gain) Loss on Derivatives, Net $67,714 ($26,065 ) $97,310 ($51,381 )
Schedule of Cash Received for Derivatives	The net cash received (paid) for settlements of commodity derivatives and deferred premium obligations in the consolidated statements of cash flows for the three and six months ended June 30, 2018 and 2017 are summarized below: Three Months Ended Six Months Ended 2018 2017 2018 2017 Cash Flows from Operating Activities (In thousands) Cash Received (Paid) for Derivative Settlements, Net Crude oil derivatives ($21,210 ) $409 ($33,333 ) $3,441 NGL derivatives (756 ) — (1,188 ) — Natural gas derivatives 488 (104 ) 540 (1,253 ) Deferred premium obligations (2,605 ) (566 ) (4,467 ) (930 ) Cash Received (Paid) for Derivative Settlements, Net ($24,083 ) ($261 ) ($38,448 ) $1,258
Crude Oil
Derivative [Line Items]
Schedule of Derivative Instruments	The following table sets forth a summary of the Company’s outstanding crude oil derivative positions as of June 30, 2018 at weighted average contract prices: Period Type of Contract Index Volumes (Bbls/d) Fixed Price ($/Bbl) Sub-Floor Price ($/Bbl) Floor Price ($/Bbl) Ceiling Price ($/Bbl) 2018 Q3-Q4 Price Swaps NYMEX WTI 6,000 $49.55 $— $— $— Q3-Q4 Three-Way Collars NYMEX WTI 24,000 — 39.38 49.06 60.14 Q3-Q4 Basis Swaps LLS-Cushing WTI (1) 18,000 5.11 — — — Q3-Q4 Basis Swaps Midland WTI-Cushing WTI (2) 6,000 (0.10 ) — — — Q3-Q4 Net Sold Call Options NYMEX WTI 3,388 — — — 71.33 2019 Q1-Q4 Three-Way Collars NYMEX WTI 15,000 — 41.00 49.72 62.48 Q1-Q2 Basis Swaps Midland WTI-Cushing WTI (2) 3,000 (3.83 ) — — — Q3 Basis Swaps Midland WTI-Cushing WTI (2) 3,500 (4.18 ) — — — Q4 Basis Swaps Midland WTI-Cushing WTI (2) 6,000 (3.71 ) — — — Q1-Q4 Net Sold Call Options NYMEX WTI 3,875 — — — 73.66 2020 Q1-Q4 Net Sold Call Options NYMEX WTI 4,575 — — — 75.98 (1) The index price paid under these basis swaps is LLS and the index price received is Cushing WTI plus the fixed price differential. (2) The index price paid under these basis swaps is Midland WTI and the index price received is Cushing WTI less the fixed price differential. In August 2018, the Company entered into the following crude oil derivative positions at the weighted average contract prices summarized below: Period Type of Contract Index Volumes (Bbls/d) Fixed Price ($/Bbl) 2019 Q1 Basis Swaps Midland WTI-Cushing WTI (1) 2,500 ($6.94 ) Q2 Basis Swaps Midland WTI-Cushing WTI (1) 3,000 (6.94 ) Q3 Basis Swaps Midland WTI-Cushing WTI (1) 3,500 (6.94 ) Q4 Basis Swaps Midland WTI-Cushing WTI (1) 5,000 (4.00 ) 2020 Q1 Basis Swaps Midland WTI-Cushing WTI (1) 1,000 (1.90 ) (1) The index price paid under these basis swaps is Midland WTI and the index price received is Cushing WTI less the fixed price differential.
Natural Gas Liquids
Derivative [Line Items]
Schedule of Derivative Instruments	The following table sets forth a summary of the Company’s outstanding NGL derivative positions as of June 30, 2018 at weighted average contract prices: Period Type of Contract Index Volumes (Bbls/d) Fixed Price ($/Bbl) 2018 Q3-Q4 Price Swaps Ethane - OPIS Mont Belvieu Non-TET 2,200 $12.01 Q3-Q4 Price Swaps Propane - OPIS Mont Belvieu Non-TET 1,500 34.23 Q3-Q4 Price Swaps Butane - OPIS Mont Belvieu Non-TET 200 38.85 Q3-Q4 Price Swaps Isobutane - OPIS Mont Belvieu Non-TET 600 38.98 Q3-Q4 Price Swaps Natural Gasoline - OPIS Mont Belvieu Non-TET 600 55.23
Natural Gas
Derivative [Line Items]
Schedule of Derivative Instruments	The following table sets forth a summary of the Company’s outstanding natural gas derivative positions as of June 30, 2018 at weighted average contract prices: Period Type of Contract Index Volumes (MMBtu/d) Fixed Price ($/MMBtu) Ceiling Price ($/MMBtu) 2018 Q3-Q4 Price Swaps NYMEX HH 25,000 $3.01 $— Q3-Q4 Sold Call Options NYMEX HH 33,000 — 3.25 2019 Q1-Q4 Sold Call Options NYMEX HH 33,000 — 3.25 2020 Q1-Q4 Sold Call Options NYMEX HH 33,000 — 3.50

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following tables summarize the Company’s commodity derivative instrument and contingent consideration arrangement assets and liabilities measured at fair value on a recurring basis as of June 30, 2018 and December 31, 2017 : June 30, 2018 Level 1 Level 2 Level 3 (In thousands) Assets Commodity derivative instruments $— $1,163 $— Contingent Niobrara Consideration — — 9,970 Contingent Marcellus Consideration — — 1,530 Contingent Utica Consideration — — 10,545 Liabilities Commodity derivative instruments $— ($131,398 ) $— Contingent ExL Consideration — — (102,055 ) December 31, 2017 Level 1 Level 2 Level 3 (In thousands) Assets Commodity derivative instruments $— $— $— Contingent Niobrara Consideration — — — Contingent Marcellus Consideration — — 2,205 Contingent Utica Consideration — — 7,985 Liabilities Commodity derivative instruments $— ($83,828 ) $— Contingent ExL Consideration — — (85,625 )
Fair Value, Assets and Liabilities Measured on Recurring Basis, Level 3 Reconciliation	Contingent Consideration Arrangements Assets Liability For the Six Months Ended June 30, 2018 (In thousands) Beginning of period $10,190 ($85,625 ) Recognition of divestiture date fair value 7,880 — Gain (loss) on changes in fair value, net (1) 3,975 (16,430 ) Transfers into (out of) Level 3 — — End of period $22,045 ($102,055 )
Schedule of Carrying Value and Fair Value of Debt Instruments	The following table presents the carrying amounts of the Company’s senior notes and other long-term debt, which are designated as Level 1 under the fair value hierarchy, net of unamortized premiums and debt issuance costs, with the fair values measured using quoted secondary market trading prices. June 30, 2018 December 31, 2017 Carrying Amount Fair Value Carrying Amount Fair Value (In thousands) 7.50% Senior Notes due 2020 $129,044 $130,325 $446,087 $459,518 6.25% Senior Notes due 2023 642,446 656,500 641,792 674,375 8.25% Senior Notes due 2025 245,817 266,250 245,605 274,375 Other long-term debt due 2028 — — 4,425 4,445

Condensed Consolidating Finan31

Condensed Consolidating Financial Information (Tables)	6 Months Ended
	Jun. 30, 2018
Condensed Consolidating Financial Information [Abstract]
Schedule Of Condensed Consolidating Balance Sheets	CARRIZO OIL & GAS, INC. CONDENSED CONSOLIDATING BALANCE SHEETS (In thousands) (Unaudited) June 30, 2018 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Assets Total current assets $3,128,244 $120,425 $— ($3,116,164 ) $132,505 Total property and equipment, net 6,445 2,562,799 3,028 (3,847 ) 2,568,425 Investment in subsidiaries (743,363 ) — — 743,363 — Other assets 8,630 12,279 — — 20,909 Total Assets $2,399,956 $2,695,503 $3,028 ($2,376,648 ) $2,721,839 Liabilities and Shareholders’ Equity Current liabilities $257,137 $3,362,551 $3,028 ($3,119,185 ) $503,531 Long-term liabilities 1,526,788 76,315 — 15,879 1,618,982 Preferred stock 172,858 — — — 172,858 Total shareholders’ equity 443,173 (743,363 ) — 726,658 426,468 Total Liabilities and Shareholders’ Equity $2,399,956 $2,695,503 $3,028 ($2,376,648 ) $2,721,839 December 31, 2017 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Assets Total current assets $3,441,633 $105,533 $— ($3,424,288 ) $122,878 Total property and equipment, net 5,953 2,630,707 3,028 (3,878 ) 2,635,810 Investment in subsidiaries (999,793 ) — — 999,793 — Other assets 9,270 10,346 — — 19,616 Total Assets $2,457,063 $2,746,586 $3,028 ($2,428,373 ) $2,778,304 Liabilities and Shareholders’ Equity Current liabilities $165,701 $3,631,401 $3,028 ($3,427,308 ) $372,822 Long-term liabilities 1,689,466 114,978 — 15,879 1,820,323 Preferred stock 214,262 — — — 214,262 Total shareholders’ equity 387,634 (999,793 ) — 983,056 370,897 Total Liabilities and Shareholders’ Equity $2,457,063 $2,746,586 $3,028 ($2,428,373 ) $2,778,304
Schedule Of Condensed Consolidating Statements Of Operations	CARRIZO OIL & GAS, INC. CONDENSED CONSOLIDATING STATEMENTS OF INCOME (In thousands) (Unaudited) Three Months Ended June 30, 2018 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Total revenues $19 $263,954 $— $— $263,973 Total costs and expenses 106,335 121,869 — (23 ) 228,181 Income (loss) before income taxes (106,316 ) 142,085 — 23 35,792 Income tax expense — (483 ) — — (483 ) Equity in income of subsidiaries 141,602 — — (141,602 ) — Net income $35,286 $141,602 $— ($141,579 ) $35,309 Dividends on preferred stock (4,474 ) — — — (4,474 ) Accretion on preferred stock (740 ) — — — (740 ) Loss on redemption of preferred stock — — — — — Net income attributable to common shareholders $30,072 $141,602 $— ($141,579 ) $30,095 Three Months Ended June 30, 2017 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Total revenues $174 $166,309 $— $— $166,483 Total costs and expenses 7,731 102,415 — 31 110,177 Income (loss) before income taxes (7,557 ) 63,894 — (31 ) 56,306 Income tax expense — — — — — Equity in income of subsidiaries 63,894 — — (63,894 ) — Net income $56,337 $63,894 $— ($63,925 ) $56,306 Dividends on preferred stock — — — — — Accretion on preferred stock — — — — — Loss on redemption of preferred stock — — — — — Net income attributable to common shareholders $56,337 $63,894 $— ($63,925 ) $56,306 CARRIZO OIL & GAS, INC. CONDENSED CONSOLIDATING STATEMENTS OF INCOME (In thousands) (Unaudited) Six Months Ended June 30, 2018 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Total revenues $39 $489,214 $— $— $489,253 Total costs and expenses 193,700 231,982 — (32 ) 425,650 Income (loss) before income taxes (193,661 ) 257,232 — 32 63,603 Income tax expense — (802 ) — — (802 ) Equity in income of subsidiaries 256,430 — — (256,430 ) — Net income $62,769 $256,430 $— ($256,398 ) $62,801 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 attributable to common shareholders $44,806 $256,430 $— ($256,398 ) $44,838 Six Months Ended June 30, 2017 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Total revenues $256 $317,582 $— $— $317,838 Total costs and expenses 26,599 194,871 — 41 221,511 Income (loss) before income taxes (26,343 ) 122,711 — (41 ) 96,327 Income tax expense — — — — — Equity in income of subsidiaries 122,711 — — (122,711 ) — Net income $96,368 $122,711 $— ($122,752 ) $96,327 Dividends on preferred stock — — — — — Accretion on preferred stock — — — — — Loss on redemption of preferred stock — — — — — Net income attributable to common shareholders $96,368 $122,711 $— ($122,752 ) $96,327
Schedule Of Condensed Consolidating Statements Of Cash Flows	CARRIZO OIL & GAS, INC. CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS (In thousands) (Unaudited) Six Months Ended June 30, 2018 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Net cash provided by (used in) operating activities ($158,309 ) $434,181 $— $— $275,872 Net cash provided by (used in) investing activities 348,235 (84,355 ) — (349,826 ) (85,946 ) Net cash used in financing activities (197,367 ) (349,826 ) — 349,826 (197,367 ) Net decrease in cash and cash equivalents (7,441 ) — — — (7,441 ) Cash and cash equivalents, beginning of period 9,540 — — — 9,540 Cash and cash equivalents, end of period $2,099 $— $— $— $2,099 Six Months Ended June 30, 2017 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Net cash provided by (used in) operating activities ($77,501 ) $256,656 $— $— $179,155 Net cash used in investing activities (109,780 ) (364,887 ) — 108,231 (366,436 ) Net cash provided by financing activities 185,315 108,231 — (108,231 ) 185,315 Net decrease in cash and cash equivalents (1,966 ) — — — (1,966 ) Cash and cash equivalents, beginning of period 4,194 — — — 4,194 Cash and cash equivalents, end of period $2,228 $— $— $— $2,228

Supplemental Cash Flow Inform32

Supplemental Cash Flow Information (Tables)	6 Months Ended
	Jun. 30, 2018
Supplemental Cash Flow Elements [Abstract]
Schedule of Cash Flow, Supplemental Disclosures	Supplemental cash flow disclosures and non-cash investing activities are presented below: Six Months Ended 2018 2017 (In thousands) Supplemental cash flow disclosures: Cash paid for interest, net of amounts capitalized $29,853 $39,603 Non-cash investing activities: Increase in capital expenditure payables and accruals $35,543 $48,395 Contingent consideration arrangement related to divestitures of oil and gas properties (7,880 ) —

Subsequent Events (Tables)

Subsequent Events (Tables)	6 Months Ended
	Jun. 30, 2018
Crude Oil
Derivative [Line Items]
Schedule of Derivative Instruments	The following table sets forth a summary of the Company’s outstanding crude oil derivative positions as of June 30, 2018 at weighted average contract prices: Period Type of Contract Index Volumes (Bbls/d) Fixed Price ($/Bbl) Sub-Floor Price ($/Bbl) Floor Price ($/Bbl) Ceiling Price ($/Bbl) 2018 Q3-Q4 Price Swaps NYMEX WTI 6,000 $49.55 $— $— $— Q3-Q4 Three-Way Collars NYMEX WTI 24,000 — 39.38 49.06 60.14 Q3-Q4 Basis Swaps LLS-Cushing WTI (1) 18,000 5.11 — — — Q3-Q4 Basis Swaps Midland WTI-Cushing WTI (2) 6,000 (0.10 ) — — — Q3-Q4 Net Sold Call Options NYMEX WTI 3,388 — — — 71.33 2019 Q1-Q4 Three-Way Collars NYMEX WTI 15,000 — 41.00 49.72 62.48 Q1-Q2 Basis Swaps Midland WTI-Cushing WTI (2) 3,000 (3.83 ) — — — Q3 Basis Swaps Midland WTI-Cushing WTI (2) 3,500 (4.18 ) — — — Q4 Basis Swaps Midland WTI-Cushing WTI (2) 6,000 (3.71 ) — — — Q1-Q4 Net Sold Call Options NYMEX WTI 3,875 — — — 73.66 2020 Q1-Q4 Net Sold Call Options NYMEX WTI 4,575 — — — 75.98 (1) The index price paid under these basis swaps is LLS and the index price received is Cushing WTI plus the fixed price differential. (2) The index price paid under these basis swaps is Midland WTI and the index price received is Cushing WTI less the fixed price differential. In August 2018, the Company entered into the following crude oil derivative positions at the weighted average contract prices summarized below: Period Type of Contract Index Volumes (Bbls/d) Fixed Price ($/Bbl) 2019 Q1 Basis Swaps Midland WTI-Cushing WTI (1) 2,500 ($6.94 ) Q2 Basis Swaps Midland WTI-Cushing WTI (1) 3,000 (6.94 ) Q3 Basis Swaps Midland WTI-Cushing WTI (1) 3,500 (6.94 ) Q4 Basis Swaps Midland WTI-Cushing WTI (1) 5,000 (4.00 ) 2020 Q1 Basis Swaps Midland WTI-Cushing WTI (1) 1,000 (1.90 ) (1) The index price paid under these basis swaps is Midland WTI and the index price received is Cushing WTI less the fixed price differential.

Summary of Significant Accoun34

Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Summary Of Significant Accounting Policies [Line Items]
Accrued Fees and Other Revenue Receivable	$ 87.1	$ 85.6

Summary of Significant Accoun35

Summary of Significant Accounting Policies (Schedule of Impact of Adoption) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Crude oil revenues	$ 229,798	$ 142,806	$ 424,717	$ 270,898
Natural gas liquids revenues	21,269	7,786	38,171	15,211
Natural gas revenues	12,906	15,891	26,365	31,729
Oil and Gas Sales Revenue	263,973	166,483	489,253	317,838
Lease operating	35,151	36,048	74,424	65,893
Income before income taxes	35,792	$ 56,306	63,603	$ 96,327
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Crude oil revenues	229,658		424,452
Natural gas liquids revenues	20,139		36,235
Natural gas revenues	12,272		25,159
Oil and Gas Sales Revenue	262,069		485,846
Lease operating	33,247		71,017
Income before income taxes	35,792		63,603
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Crude oil revenues	140		265
Natural gas liquids revenues	1,130		1,936
Natural gas revenues	634		1,206
Oil and Gas Sales Revenue	1,904		3,407
Lease operating	1,904		3,407
Income before income taxes	$ 0		$ 0
Crude Oil
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Percent Difference Between Revenue Guidance In Effect Before And After Topic 606	0.10%		0.10%
Natural Gas Liquids
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Percent Difference Between Revenue Guidance In Effect Before And After Topic 606	5.60%		5.30%
Natural Gas
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Percent Difference Between Revenue Guidance In Effect Before And After Topic 606	5.20%		4.80%
Total Oil and Gas
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Percent Difference Between Revenue Guidance In Effect Before And After Topic 606	0.70%		0.70%
Lease Operating Expense
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Percent Difference Between Revenue Guidance In Effect Before And After Topic 606	5.70%		4.80%
Income Before Income Taxes
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Percent Difference Between Revenue Guidance In Effect Before And After Topic 606	0.00%		0.00%

Summary of Significant Accoun36

Summary of Significant Accounting Policies (Schedule of Earnings Per Share Reconciliation) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net Income Attributable to Common Shareholders	$ 30,095	$ 56,306	$ 44,838	$ 96,327
Basic (in shares)	82,058	65,767	81,802	65,479
Effect of dilutive instruments	1,795	141	1,438	387
Diluted weighted average common shares outstanding	83,853	65,908	83,240	65,866
Net Income (Loss) - basic (in dollars per share)	$ 0.37	$ 0.86	$ 0.55	$ 1.47
Net Income (Loss) - diluted (in dollars per share)	$ 0.36	$ 0.85	$ 0.54	$ 1.46

Summary of Significant Accoun37

Summary of Significant Accounting Policies (Reconciliation of Common Shares Outstanding to Diluted) (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Schedule of Reconciliation of the Weighted Average Common Shares Outstanding [Line Items]
Basic (in shares)	82,058	65,767	81,802	65,479
Diluted (in shares)	83,853	65,908	83,240	65,866
Restricted Stock Awards And Units [Member]
Schedule of Reconciliation of the Weighted Average Common Shares Outstanding [Line Items]
Incremental Common Shares Attributable to Dilutive Effect of Nonvested Shares with Forfeitable Dividends	833	141	640	387
Performance Shares [Member]
Schedule of Reconciliation of the Weighted Average Common Shares Outstanding [Line Items]
Incremental Common Shares Attributable to Dilutive Effect of Nonvested Shares with Forfeitable Dividends	134	0	158	0
Warrant [Member]
Schedule of Reconciliation of the Weighted Average Common Shares Outstanding [Line Items]
Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants	828	0	640	0

Summary of Significant Accoun38

Summary of Significant Accounting Policies (Schedule of Antidilutive Shares Excluded from Earnings Per Share) (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	16	209	19	78
Restricted Stock Award And Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	16	101	17	16
Performance Shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	108	2	62
Warrant [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	0	0	0

Acquisitions and Divestitures39

Acquisitions and Divestitures (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended			12 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Dec. 31, 2017	Dec. 11, 2017
Business Acquisition [Line Items]
Payments to Acquire Oil and Gas Property		$ 0		$ 16,533
Proceeds from divestitures of oil and gas properties, net		$ 345,789		$ 18,201
Subsequent Event [Member]
Business Acquisition [Line Items]
Proceeds from divestitures of oil and gas properties, net	$ 31,400
ExL Acquisition
Business Acquisition [Line Items]
Payments to Acquire Oil and Gas Property					$ 679,800
Niobrara Divestiture
Business Acquisition [Line Items]
Proceeds from divestitures of oil and gas properties, net			$ 134,700
Eagle Ford Shale Divestiture
Business Acquisition [Line Items]
Proceeds from divestitures of oil and gas properties, net			$ 245,700
Sale Price of Oil and Gas Property and Equipment						$ 245,000

Acquisitions (Pro Forma Informa

Acquisitions (Pro Forma Information) (Details) - ExL Acquisition - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018
Business Acquisition [Line Items]
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual	$ 52.8	$ 96.2
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual	$ 42	$ 76.9

Property and Equipment, Net (Na

Property and Equipment, Net (Narrative) (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)$ / Boe	Jun. 30, 2017USD ($)$ / Boe	Jun. 30, 2018USD ($)$ / Boe	Jun. 30, 2017USD ($)$ / Boe
Property, Plant and Equipment [Line Items]
Average depreciation, depletion and amortization, per Boe | $ / Boe	13.74	12.43	13.73	12.55
Internal costs capitalized, Oil and Gas producing activities	$ 6.1	$ 1.9	$ 12.7	$ 7.3
Capitalized interest	$ 8.7	$ 4	$ 19.1	$ 7.8

Property And Equipment, Net (Sc

Property And Equipment, Net (Schedule Of Property And Equipment) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Proved properties	$ 5,744,434	$ 5,615,153
Accumulated depreciation, depletion and amortization and impairments	(3,784,483)	(3,649,806)
Proved properties, net	1,959,951	1,965,347
Unproved properties, not being amortized
Unevaluated leasehold and seismic costs	539,836	612,589
Capitalized interest	58,056	47,698
Total unproved properties, not being amortized	597,892	660,287
Other property and equipment	27,223	25,625
Accumulated depreciation	(16,641)	(15,449)
Other property and equipment, net	10,582	10,176
Total property and equipment, net	$ 2,568,425	$ 2,635,810

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Taxes [Line Items]
U.S. federal statutory corporate pretax rate		35.00%		21.00%
State and Local Income Taxes	$ 487		$ 1,017	$ 806	$ 1,727
Deferred Tax Assets, Net	0			0
Deferred Tax Assets, Valuation Allowance	316,489	$ 333,029		316,489
Change in Deferred Tax Assets Valuation Allowance	$ (8,048)		$ (20,948)	$ (16,449)	$ (38,317)

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, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income before income taxes	$ 35,792	$ 56,306	$ 63,603	$ 96,327
Income tax expense at the statutory rate	(7,517)	(19,707)	(13,357)	(33,714)
State income tax expense, net of U.S. federal income taxes	(487)	(1,017)	(806)	(1,727)
Tax shortfalls from stock-based compensation expense	(16)	(164)	(2,542)	(2,756)
Decrease in deferred tax assets valuation allowance	8,048	20,948	16,449	38,317
Other	(511)	(60)	(546)	(120)
Income tax expense	$ (483)	$ 0	$ (802)	$ 0

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details) $ in Thousands	1 Months Ended	2 Months Ended	3 Months Ended			6 Months Ended
	May 31, 2018USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)Rate	Jun. 30, 2017USD ($)	May 04, 2018USD ($)	May 03, 2018	Jan. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Debt Instrument [Line Items]
Debt Instrument, Repurchased Face Amount				$ 320,000
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	$ 8,676	$ 0
Write off of Deferred Debt Issuance Cost				$ 2,700
Redemption price, percentage of principal amount		101.875%	101.875%			101.875%
Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity		$ 1,000,000	$ 1,000,000			$ 1,000,000		$ 1,000,000		$ 830,000	$ 900,000
Line of Credit Facility, Elected Borrowing Capacity		900,000	900,000			900,000		$ 900,000		$ 800,000
Line of credit facility amount outstanding		$ 485,000	$ 485,000			$ 485,000					291,300
Debt, Weighted Average Interest Rate		3.74%	3.74%			3.74%
Ratio of total debt to EBITDA						2.53
Current Ratio		1.49	1.49			1.49
Pre-Tax SEC PV10 Reserve Value Percentage | Rate						90.00%
Federal funds rate plus percentage		0.50%	0.50%			0.50%
Adjusted LIBO rate plus percentage		1.00%	1.00%			1.00%
Senior Secured Revolving Credit Facility [Member] | Maximum [Member]
Debt Instrument [Line Items]
Margin for eurodollar loans		2.50%		3.00%
Ratio of total debt to EBITDA						4
Senior Secured Revolving Credit Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
Margin for eurodollar loans		1.50%		2.00%
Current Ratio		1	1			1
7.50% Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		7.50%	7.50%			7.50%
Long term debt		$ 130,000	$ 130,000			$ 130,000					450,000
8.25% Senior Notes [Member]
Debt Instrument [Line Items]
Long term debt		250,000	250,000			250,000					250,000
Other Long Term Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage									4.375%
Cash paid for debt redemption	$ 4,500
Accrued interest paid associated with redemption of debt	$ 100
Redemption price, percentage of principal amount									100.00%
Long term debt		$ 0	$ 0			$ 0					$ 4,425
Less than 25 percent [Member] | Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Margin for eurodollar loans		1.50%
Line of Credit Facility, Commitment Fee Percentage		0.375%
Margin for base rate loans		0.50%
Greater than or equal to 90 percent [Member] | Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Margin for eurodollar loans		2.50%
Line of Credit Facility, Commitment Fee Percentage		0.50%
Margin for base rate loans		1.50%

Long-Term Debt (Schedule of Lon

Long-Term Debt (Schedule of Long-Term Debt) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long-term debt	$ 1,502,307	$ 1,629,209
Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility amount outstanding	485,000	291,300
7.50% Senior Notes [Member]
Debt Instrument [Line Items]
Long term debt	130,000	450,000
Debt instrument, unamortized premium	139	579
Unamortized Debt Issuance Expense	(1,095)	(4,492)
6.25% Senior Notes [Member]
Debt Instrument [Line Items]
Long term debt	650,000	650,000
Unamortized Debt Issuance Expense	(7,554)	(8,208)
8.25% Senior Notes [Member]
Debt Instrument [Line Items]
Long term debt	250,000	250,000
Unamortized Debt Issuance Expense	(4,183)	(4,395)
Other Long Term Debt [Member]
Debt Instrument [Line Items]
Long term debt	$ 0	$ 4,425

Long-Term Debt (Interest and Co

Long-Term Debt (Interest and Commitment Fee Rates) (Details) - Senior Secured Revolving Credit Facility [Member]	2 Months Ended
	Jun. 30, 2018
Less than 25 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 25 percent but less than 50 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	0.375%
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	1.00%
Margin for eurodollar loans	2.00%
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	1.25%
Margin for eurodollar loans	2.25%
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	1.50%
Margin for eurodollar loans	2.50%
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, 2018	Sep. 30, 2017	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jan. 24, 2018	Dec. 31, 2017	Aug. 10, 2017
Preferred Stock Disclosure [Line Items]
Preferred Stock, Par Value								$ 250,000
Preferred Stock, Shares Issued	200,000			200,000			250,000	250,000
Preferred Stock, Dividend Rate, Percentage	8.875%
Preferred Stock, Par or Stated Value Per Share	$ 0.01			$ 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
Sale of preferred stock, net of issuance costs		$ 236,404
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
Loss on redemption of preferred stock	0		$ 0	$ 7,133	$ 0
Preferred Stock Redemption Costs				100
Preferred Stock Redemption Premium				7,000
Total Consideration for Repurchase of Preferred Stock				50,030
Redemption of Preferred Stock				$ (42,897)
Preferred Stock, Redemption Premium, Percentage				104.4375%
Preferred Stock, Percent of Ownership to be Able to Vote		50.00%
Preferred Stock, Prohibited Distributions		$ 15,000
Dividends on preferred stock	(4,474)			$ (9,337)	0
Accretion on preferred stock	$ (740)		$ 0	$ (1,493)	$ 0
On or before the seventh anniversary of the Preferred Stock Issuance Date [Domain]
Preferred Stock Disclosure [Line Items]
Preferred Stock, Dividend Rate, Percentage		12.00%
After August 10, 2024 [Domain]
Preferred Stock Disclosure [Line Items]
Preferred Stock, Dividend Rate, Percentage		12.00%
Libor Rate to Calculate Preferred Stock Dividend Rate		10.00%

Preferred Stock (Schedule of Di

Preferred Stock (Schedule of Dividends Paid in Common Stock) (Details)	Jun. 30, 2018Rate
Preferred Stock Dividend Paid in Common Stock First Year [Member]
Schedule of Preferred Stock Dividend Paid in Common Stock [Line Items]
Percent of Dividend Payable in Common Stock	100.00%
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 Redemption Premiums) (Details)	6 Months Ended
	Jun. 30, 2018
Schedule of Preferred Stock Redemption Premiums [Line Items]
Preferred Stock, Redemption Premium, Percentage	104.4375%
Preferred Stock Redemption Fourth Year [Member]
Schedule of Preferred Stock Redemption Premiums [Line Items]
Preferred Stock, Redemption Premium, Percentage	104.4375%
Preferred Stock Redemption Fifth Year [Member] [Member]
Schedule of Preferred Stock Redemption Premiums [Line Items]
Preferred Stock, Redemption Premium, Percentage	102.21875%
Preferred Stock Redemption Sixth Year [Member]
Schedule of Preferred Stock Redemption Premiums [Line Items]
Preferred Stock, Redemption Premium, Percentage	100.00%

Preferred Stock (Schedule of 51

Preferred Stock (Schedule of Preferred Stock Activity) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	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, 2018 and 250,000 issued and outstanding as of December 31, 2017	$ 172,858,000		$ 172,858,000		$ 214,262,000
Redemption of Preferred Stock			(42,897,000)
Accretion on preferred stock	$ (740,000)	$ 0	$ (1,493,000)	$ 0

Shareholders' Equity and Stoc52

Shareholders' Equity and Stock Incentive Plans (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Available for Grant	2,675,000	2,675,000
Common stock, shares authorized (in shares)	180,000,000	180,000,000		180,000,000
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ratio of stock based compensation shares to common shares		1
Restricted Stock Awards And Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ratio of stock based compensation shares to common shares		1.35
Granted Shares/Units		1,348,415
Fair Value of Shares Issued		$ 19.7
Vesting period, in years		3 years
Nonvested Awards, Compensation Cost Not yet Recognized	$ 30.5	$ 30.5
Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition		2 years 2 months 12 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period		10,993
Equity Instruments Other than Options, Vested in Period		608,904
Restricted Stock Awards And Units [Member] | Annual Grant of Long-Term Equity Incentive Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted Shares/Units		1,343,412
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ratio of stock based compensation shares to common shares		1
Fair Value of Shares Issued		$ 4.9
Vesting period, in years		3 years
Expiration period after date of grant, in years		7 years
Liability For Cash Stock Appreciation Rights		$ 8.7
Nonvested Awards, Compensation Cost Not yet Recognized	11.3	$ 11.3
Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition		2 years 7 months 6 days
SARs, Granted		616,686
Stock Appreciation Rights (SARs) [Member] | Other Noncurrent Liabilities [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Liability For Cash Stock Appreciation Rights			$ 4.4
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted Shares/Units		93,771
Fair Value of Shares Issued		$ 1.8
Vesting period, in years		3 years
Nonvested Awards, Compensation Cost Not yet Recognized	$ 2.9	$ 2.9
Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition		2 years 2 months 12 days
Performance shares vested per TSR ranking	56,517
Unearned Shares due to Market Condition		7,059
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period		0
Equity Instruments Other than Options, Vested in Period		49,458
Vesting percentage of target performance shares granted	88.00%
2017 Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Available for Grant	326,774	326,774

Shareholders' Equity and Stoc53

Shareholders' Equity and Stock Incentive Plans (Summary of Restricted Stock Award and Unit Activity) (Details) - Restricted Stock Awards And Units [Member]	6 Months Ended
	Jun. 30, 2018$ / sharesshares
Restricted Stock Awards and Units [Abstract]
Unvested Shares/Units, Beginning of Period | shares	1,482,655
Granted Shares/Units | shares	1,348,415
Vested Shares/Units | shares	(608,904)
Forfeited Shares/Units | shares	(10,993)
Unvested Shares/Units, End of Period | shares	2,211,173
Weighted Average Grant Date Fair Value [Abstract]
Grant Date Fair Value, Beginning of Period (USD per share) | $ / shares	$ 28.07
Granted, Grant Date Fair Value (USD per share) | $ / shares	14.68
Vested, Grant Date Fair Value (USD per share) | $ / shares	31.43
Forfeited, Grant Date Fair Value (USD per share) | $ / shares	19.17
Grant Date Fair Value, End of Period (USD per share) | $ / shares	$ 19.02

Shareholders' Equity and Stoc54

Shareholders' Equity and Stock Incentive Plans (Summary of SARs Activity) (Details) - Stock Appreciation Rights (SARs) [Member] $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2018USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
SARs, Outstanding, Beginning of period | shares	714,238
SARs, Granted | shares	616,686
SARs, Exercised | shares	0
SARs, Forfeitures | shares	0
SARs, Expirations | shares	0
SARs, Outstanding, End of period | shares	1,330,924
SARs, Vested, End of Period | shares	543,018
SARs, Exercisable, End of Period | shares	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 | $ / shares	$ 27.12
Weighted Average Exercise Prices, Granted | $ / shares	14.67
Weighted Average Exercise Prices, Exercised | $ / shares	0
Weighted Average Exercise Prices, Forfeitures | $ / shares	0
Weighted Average Exercise Prices, Expired | $ / shares	0
Weighted Average Exercise Prices, Outstanding, End of Period | $ / shares	21.35
Weighted Average Exercise Prices, Vested, End of Period | $ / shares	27.18
Weighted Average Exercise Prices, Exercisable, End of Period | $ / shares	$ 27.18
Cash paid at exercises, Stock Appreciation Rights | $	$ 0
Weighted Average Remaining Life, Outstanding, End of Period	4 years 9 months 29 days
Weighted Average Remaining Life, Exercisable, End of Period	3 years 14 days
Aggregate Intrinsic Value, Outstanding, End of Period | $	$ 9.1
Aggregate Intrinsic Value, Exercisable, End of Period | $	$ 0.5

Shareholders' Equity and Stoc55

Shareholders' Equity and Stock Incentive Plans (Summary of SARs Fair Value Assumptions) (Details) - Stock Appreciation Rights (SARs) [Member]	6 Months Ended
	Jun. 30, 2018Rate
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected Term	6 years
Expected Volatility Rate	54.30%
Risk-free Interest Rate	2.80%
Dividend Yield	0.00%

Shareholders' Equity and Stoc56

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

Shareholders' Equity and Stoc57

Shareholders' Equity and Stock Incentive Plans (Summary of Performance Share Awards Fair Value Assumptions) (Details) - Performance Shares [Member]	6 Months Ended
	Jun. 30, 2018Rate
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of simulations performed	500,000
Expected Term	3 years
Expected Volatility Rate	61.50%
Risk-free Interest Rate	2.40%
Dividend Yield	0.00%

Shareholders' Equity and Stoc58

Shareholders' Equity and Stock Incentive Plans (Schedule of Share-Based Compensation Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated Share-based Compensation Expense	$ 10,914	$ 1,815	$ 15,140	$ 4,684
Less: amounts capitalized	(3,708)	(233)	(4,416)	(1,088)
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost	7,206	1,582	10,724	3,596
Restricted Stock Awards And Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated Share-based Compensation Expense	4,720	5,024	9,804	10,873
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated Share-based Compensation Expense	5,788	(3,783)	4,373	(7,469)
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated Share-based Compensation Expense	$ 406	$ 574	$ 963	$ 1,280

Derivative Instruments (Schedul

Derivative Instruments (Schedule of Crude Oil Derivative Positions) (Details) - Crude Oil	Jun. 30, 2018bbl / d$ / bbls
Q3 - Q4 2018 | Fixed Price Swaps
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	6,000
Weighted Average Fixed Price ($/Bbl)	(49.55)
Q3 - Q4 2018 | Basis Swaps | LLS-NYMEX Price Differential
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	18,000
Weighted Average Fixed Price ($/Bbl)	(5.11)
Q3 - Q4 2018 | Basis Swaps | Midland-NYMEX Price Differential
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	6,000
Weighted Average Fixed Price ($/Bbl)	(0.10)
Q3 - Q4 2018 | Three-way Collars
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	24,000
Weighted Average Sub-Floor Price ($/Bbls)	39.38
Weighted Average Floor Price ($/Bbls)	49.06
Weighted Average Ceiling Price ($/Bbls)	60.14
Q3 - Q4 2018 | Call Option
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	3,388
Weighted Average Ceiling Price ($/Bbls)	71.33
1H 2019 | Basis Swaps | Midland-NYMEX Price Differential
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	3,000
Weighted Average Fixed Price ($/Bbl)	(3.83)
Q3 2019 | Basis Swaps | Midland-NYMEX Price Differential
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	3,500
Weighted Average Fixed Price ($/Bbl)	(4.18)
Q4 2019 | Basis Swaps | Midland-NYMEX Price Differential
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	6,000
Weighted Average Fixed Price ($/Bbl)	(3.71)
FY 2019 | Three-way Collars
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	15,000
Weighted Average Sub-Floor Price ($/Bbls)	41
Weighted Average Floor Price ($/Bbls)	49.72
Weighted Average Ceiling Price ($/Bbls)	62.48
FY 2019 | Call Option
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	3,875
Weighted Average Ceiling Price ($/Bbls)	73.66
FY 2020 | Call Option
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	4,575
Weighted Average Ceiling Price ($/Bbls)	75.98

Derivative Instruments (Sched60

Derivative Instruments (Schedule of NGL Derivative Positions) (Details) - Q3 - Q4 2018 - Natural Gas Liquids - Fixed Price Swaps	Jun. 30, 2018bbl / d$ / bbls
OPIS Purity Ethane Mont Belvieu Non-TET
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	2,200
Weighted Average Fixed Price ($/Bbl) | $ / bbls	12.01
OPIS Propane Mont Belvieu Non-TET
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	1,500
Weighted Average Fixed Price ($/Bbl) | $ / bbls	34.23
OPIS Normal Butane Mont Belvieu Non-TET
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	200
Weighted Average Fixed Price ($/Bbl) | $ / bbls	38.85
OPIS Isobutane Mont Belvieu Non-TET
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	600
Weighted Average Fixed Price ($/Bbl) | $ / bbls	38.98
OPIS Natural Gasoline Mont Belvieu Non-TET
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	600
Weighted Average Fixed Price ($/Bbl) | $ / bbls	55.23

Derivative Instruments (Sched61

Derivative Instruments (Schedule of Natural Gas Derivative Positions) (Details) - Natural Gas	Jun. 30, 2018MMBTU / d$ / MMBTU
Q3 - Q4 2018 | Fixed Price Swaps
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d	25,000
Weighted Average Fixed Price ($/MMBtu) | $ / MMBTU	3.01
Q3 - Q4 2018 | Call Option
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d	33,000
Weighted Average Ceiling Price ($/MMBtu) | $ / MMBTU	3.25
FY 2019 | Call Option
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d	33,000
Weighted Average Ceiling Price ($/MMBtu) | $ / MMBTU	3.25
FY 2020 | Call Option
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d	33,000
Weighted Average Ceiling Price ($/MMBtu) | $ / MMBTU	3.50

Derivative Instruments (Sched62

Derivative Instruments (Schedule of Contingent Consideration) (Details) $ in Thousands	3 Months Ended
	Jun. 30, 2018USD ($)$ / bbls$ / MMBTU
ExL Acquisition
Embedded Derivative [Line Items]
Threshold Price per Bbl for Additional Payments for Acquisition	50
Potential Additional Annual Payments for Acquisition | $	$ (50,000)
Contingent Consideration, Range of Outcomes, Value, High | $	(125,000)
Utica Shale Divestiture
Embedded Derivative [Line Items]
Potential Additional Annual Proceeds From Divestiture | $	$ 5,000
Utica Shale Divestiture | FY 2018 [Member]
Embedded Derivative [Line Items]
Threshold Price Per Bbl For Additional Proceeds From Divestiture	50
Utica Shale Divestiture | FY 2019 [Member]
Embedded Derivative [Line Items]
Threshold Price Per Bbl For Additional Proceeds From Divestiture	53
Utica Shale Divestiture | FY 2020 [Member]
Embedded Derivative [Line Items]
Threshold Price Per Bbl For Additional Proceeds From Divestiture	56
Marcellus Shale Divestiture
Embedded Derivative [Line Items]
Contingent Consideration, Range of Outcomes, Value, High | $	$ (7,500)
Potential Additional Annual Proceeds From Divestiture | $	$ 3,000
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
Marcellus Shale Divestiture | FY 2020 [Member]
Embedded Derivative [Line Items]
Threshold Price per MMBtu for Additional Payments from Divestiture | $ / MMBTU	3.30
Niobrara Divestiture
Embedded Derivative [Line Items]
Potential Additional Annual Proceeds From Divestiture | $	$ 5,000
Niobrara Divestiture | FY 2018 [Member]
Embedded Derivative [Line Items]
Threshold Price Per Bbl For Additional Proceeds From Divestiture	55
Niobrara Divestiture | FY 2019 [Member]
Embedded Derivative [Line Items]
Threshold Price Per Bbl For Additional Proceeds From Divestiture	55
Niobrara Divestiture | FY 2020 [Member]
Embedded Derivative [Line Items]
Threshold Price Per Bbl For Additional Proceeds From Divestiture	60

Derivative Instruments (Sched63

Derivative Instruments (Schedule of Derivative Instruments in Statement of Financial Position) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Derivatives, Fair Value [Line Items]
Derivative assets, current	$ 10,928		$ 0
Derivative liabilities, current	(145,520)	$ (57,121)
Derivative liabilities, noncurrent	(87,933)	(112,332)
Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	32,422	4,869
Derivative Asset, Gross Asset	42,187	4,869
Derivative Asset, Fair Value, Gross Liability	(31,259)	(4,869)
Derivative Asset, Gross Liability	(31,259)	(4,869)
Derivative, Fair Value, Net	1,163	0
Derivative assets, current	10,928	0
Other Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	13,418	9,505
Derivative Asset, Gross Asset	25,698	19,695
Derivative Asset, Fair Value, Gross Liability	(13,418)	(9,505)
Derivative Asset, Gross Liability	(13,418)	(9,505)
Derivative, Fair Value, Net	0	0
Derivative assets, noncurrent	12,280	10,190
Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net	(97,140)	(57,121)
Derivative Deferred Premium, Net	0	0
Derivative Liability, Fair Value, Gross Liability	(118,953)	(52,671)
Derivative Liability, Deferred Premiums, Gross Liability	(9,446)	(9,319)
Derivative Liability, Contingent Payment, Gross Liability	(48,380)
Derivative Liability, Gross Liability	(176,779)	(61,990)
Derivative Liability, Fair Value, Gross Asset	21,813	(4,450)
Derivative Liability, Deferred Premiums, Gross Asset	9,446	(9,319)
Derivative Liability, Gross Asset	31,259	4,869
Business Combination, Contingent Consideration, Liability	(48,380)
Derivative liabilities, current	(145,520)	(57,121)
Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net	(34,258)	(26,707)
Derivative Deferred Premium, Net	0	0
Derivative Liability, Fair Value, Gross Liability	(40,006)	(24,609)
Derivative Liability, Deferred Premiums, Gross Liability	(7,670)	(11,603)
Derivative Liability, Contingent Payment, Gross Liability	(53,675)	(85,625)
Derivative Liability, Gross Liability	(101,351)	(121,837)
Derivative Liability, Fair Value, Gross Asset	5,748	(2,098)
Derivative Liability, Deferred Premiums, Gross Asset	(7,670)	(11,603)
Derivative Liability, Contingent Payment, Gross Asset		0
Derivative Liability, Gross Asset	13,418	9,505
Business Combination, Contingent Consideration, Liability	(53,675)	(85,625)
Derivative liabilities, noncurrent	(87,933)	(112,332)
Niobrara Divestiture
Derivatives, Fair Value [Line Items]
Contingent Consideration, Current Asset	4,820
Contingent Consideration, Noncurrent Asset	5,150	0
Marcellus Shale Divestiture
Derivatives, Fair Value [Line Items]
Contingent Consideration, Current Asset	130
Contingent Consideration, Noncurrent Asset	1,400	2,205
Utica Shale Divestiture
Derivatives, Fair Value [Line Items]
Contingent Consideration, Current Asset	4,815
Contingent Consideration, Noncurrent Asset	$ 5,730	$ 7,985

Derivative Instruments (Sched64

Derivative Instruments (Schedule of (Gain) Loss on Derivative Instruments) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative Instruments, Gain (Loss), Commodity [Line Items]
(Gain) loss on derivatives, net	$ 67,714	$ (26,065)	$ 97,310	$ (51,381)
Crude Oil
Derivative Instruments, Gain (Loss), Commodity [Line Items]
(Gain) loss on derivatives, net	53,437	(29,736)	82,948	(48,163)
Natural Gas Liquids
Derivative Instruments, Gain (Loss), Commodity [Line Items]
(Gain) loss on derivatives, net	6,564	0	4,799	0
Natural Gas
Derivative Instruments, Gain (Loss), Commodity [Line Items]
(Gain) loss on derivatives, net	153	(3,883)	(2,892)	(10,719)
Deferred Premiums on Derivative Instruments
Derivative Instruments, Gain (Loss), Commodity [Line Items]
(Gain) loss on derivatives, net	0	7,554	0	7,501
ExL Acquisition
Derivative Instruments, Gain (Loss), Commodity [Line Items]
Gain (Loss) on Embedded Derivative, Net	10,600	0	16,430	0
Niobrara Divestiture
Derivative Instruments, Gain (Loss), Commodity [Line Items]
Gain (Loss) on Embedded Derivative, Net	(1,705)	0	(2,090)	0
Marcellus Shale Divestiture
Derivative Instruments, Gain (Loss), Commodity [Line Items]
Gain (Loss) on Embedded Derivative, Net	205	0	675	0
Utica Shale Divestiture
Derivative Instruments, Gain (Loss), Commodity [Line Items]
Gain (Loss) on Embedded Derivative, Net	$ (1,540)	$ 0	$ (2,560)	$ 0

Derivative Instruments (Sched65

Derivative Instruments (Schedule of Cash Received for Derivative Settlements) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Schedule Of Cash Received For Derivatives [Line Items]
Cash (paid) received for derivative settlements, net	$ (24,083)	$ (261)	$ (38,448)	$ 1,258
Crude Oil
Schedule Of Cash Received For Derivatives [Line Items]
Cash (paid) received for derivative settlements, net	(21,210)	409	(33,333)	3,441
Natural Gas Liquids
Schedule Of Cash Received For Derivatives [Line Items]
Cash (paid) received for derivative settlements, net	(756)	0	(1,188)	0
Natural Gas
Schedule Of Cash Received For Derivatives [Line Items]
Cash (paid) received for derivative settlements, net	488	(104)	540	(1,253)
Deferred Premiums on Derivative Instruments
Schedule Of Cash Received For Derivatives [Line Items]
Cash (paid) received for derivative settlements, net	$ (2,605)	$ (566)	$ (4,467)	$ (930)

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($)	Jun. 30, 2018	Jun. 30, 2017
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, 2018	Dec. 31, 2017
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	1,163	0
Derivative Liability	(131,398)	(83,828)
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	0	0
Niobrara Divestiture | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	9,970	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	0	0
Marcellus Shale Divestiture | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	1,530	2,205
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	0	0
Utica Shale Divestiture | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	10,545	7,985
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	0	0
ExL Acquisition | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	$ (102,055)	$ (85,625)

Fair Value Measurements (Sche68

Fair Value Measurements (Schedule of Assets and Liabilities, Level 3 Reconciliation) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$ 22,045	$ 10,190
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Issuances	7,880
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	3,975
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	(102,055)	$ (85,625)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Issuances	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	(16,430)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3	$ 0

Fair Value Measurements (Sche69

Fair Value Measurements (Schedule of Carrying Value and Fair Value of Debt Instruments) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
7.50% Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	$ 130,000	$ 450,000
7.50% Senior Notes [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	129,044	446,087
7.50% Senior Notes [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	130,325	459,518
6.25% Senior Notes [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	642,446	641,792
6.25% Senior Notes [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	656,500	674,375
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	245,817	245,605
8.25% Senior Notes [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	266,250	274,375
Other Long Term Debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	0	4,425
Other Long Term Debt [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	0	4,425
Other Long Term Debt [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	$ 0	$ 4,445

Condensed Consolidating Finan70

Condensed Consolidating Financial Information (Narrative) (Details)	Jun. 30, 2018
Condensed Consolidating Financial Information [Abstract]
Voting interest of the subsidiary owned by the registrant	100.00%

Condensed Consolidating Finan71

Condensed Consolidating Financial Information (Schedule Of Condensed Consolidating Balance Sheet) (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Condensed Balance Sheet Statements, Captions [Line Items]
Total current assets	$ 132,505,000	$ 122,878,000
Total property and equipment, net	2,568,425,000	2,635,810,000
Investment in subsidiaries	0	0
Other assets	20,909,000	19,616,000
Total Assets	2,721,839,000	2,778,304,000
Current liabilities	503,531,000	372,822,000
Long-term liabilities	1,618,982,000	1,820,323,000
Preferred Stock	172,858,000	214,262,000
Total shareholders’ equity	426,468,000	370,897,000
Total Liabilities and Shareholders’ Equity	2,721,839,000	2,778,304,000
Eliminations [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Total current assets	(3,116,164,000)	(3,424,288,000)
Total property and equipment, net	(3,847,000)	(3,878,000)
Investment in subsidiaries	743,363,000	999,793,000
Other assets	0	0
Total Assets	(2,376,648,000)	(2,428,373,000)
Current liabilities	(3,119,185,000)	(3,427,308,000)
Long-term liabilities	15,879,000	15,879,000
Preferred Stock	0	0
Total shareholders’ equity	726,658,000	983,056,000
Total Liabilities and Shareholders’ Equity	(2,376,648,000)	(2,428,373,000)
Parent Company [Member] | Reportable Legal Entities [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Total current assets	3,128,244,000	3,441,633,000
Total property and equipment, net	6,445,000	5,953,000
Investment in subsidiaries	(743,363,000)	(999,793,000)
Other assets	8,630,000	9,270,000
Total Assets	2,399,956,000	2,457,063,000
Current liabilities	257,137,000	165,701,000
Long-term liabilities	1,526,788,000	1,689,466,000
Preferred Stock	172,858,000	214,262,000
Total shareholders’ equity	443,173,000	387,634,000
Total Liabilities and Shareholders’ Equity	2,399,956,000	2,457,063,000
Combined Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Total current assets	120,425,000	105,533,000
Total property and equipment, net	2,562,799,000	2,630,707,000
Investment in subsidiaries	0	0
Other assets	12,279,000	10,346,000
Total Assets	2,695,503,000	2,746,586,000
Current liabilities	3,362,551,000	3,631,401,000
Long-term liabilities	76,315,000	114,978,000
Preferred Stock	0	0
Total shareholders’ equity	(743,363,000)	(999,793,000)
Total Liabilities and Shareholders’ Equity	2,695,503,000	2,746,586,000
Combined Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Total current assets	0	0
Total property and equipment, net	3,028,000	3,028,000
Investment in subsidiaries	0	0
Other assets	0	0
Total Assets	3,028,000	3,028,000
Current liabilities	3,028,000	3,028,000
Long-term liabilities	0	0
Preferred Stock	0	0
Total shareholders’ equity	0	0
Total Liabilities and Shareholders’ Equity	$ 3,028,000	$ 3,028,000

Condensed Consolidating Finan72

Condensed Consolidating Financial Information (Schedule Of Condensed Consolidating Statement Of Operations) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Condensed Income Statements, Captions [Line Items]
Total revenues	$ 263,973,000	$ 166,483,000	$ 489,253,000	$ 317,838,000
Total costs and expenses	228,181,000	110,177,000	425,650,000	221,511,000
Income (loss) before income taxes	35,792,000	56,306,000	63,603,000	96,327,000
Income tax (expense) benefit	(483,000)	0	(802,000)	0
Equity (deficit) in income of subsidiaries	0	0	0	0
Net Income (loss)	35,309,000	56,306,000	62,801,000	96,327,000
Dividends on preferred stock	(4,474,000)	0	(9,337,000)	0
Accretion on preferred stock	(740,000)	0	(1,493,000)	0
Loss on redemption of preferred stock	0	0	(7,133,000)	0
Net Income Attributable to Common Shareholders	30,095,000	56,306,000	44,838,000	96,327,000
Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Total revenues	0	0	0	0
Total costs and expenses	(23,000)	31,000	(32,000)	41,000
Income (loss) before income taxes	23,000	(31,000)	32,000	(41,000)
Income tax (expense) benefit	0	0	0	0
Equity (deficit) in income of subsidiaries	(141,602,000)	(63,894,000)	(256,430,000)	(122,711,000)
Net Income (loss)	(141,579,000)	(63,925,000)	(256,398,000)	(122,752,000)
Dividends on preferred stock	0	0	0	0
Accretion on preferred stock	0	0	0	0
Loss on redemption of preferred stock	0	0	0	0
Net Income Attributable to Common Shareholders	(141,579,000)	(63,925,000)	(256,398,000)	(122,752,000)
Parent Company [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Total revenues	19,000	174,000	39,000	256,000
Total costs and expenses	106,335,000	7,731,000	193,700,000	26,599,000
Income (loss) before income taxes	(106,316,000)	(7,557,000)	(193,661,000)	(26,343,000)
Income tax (expense) benefit	0	0	0	0
Equity (deficit) in income of subsidiaries	141,602,000	63,894,000	256,430,000	122,711,000
Net Income (loss)	35,286,000	56,337,000	62,769,000	96,368,000
Dividends on preferred stock	4,474,000	0	9,337,000	0
Accretion on preferred stock	(740,000)	0	(1,493,000)	0
Loss on redemption of preferred stock	0	0	(7,133,000)	0
Net Income Attributable to Common Shareholders	30,072,000	56,337,000	44,806,000	96,368,000
Combined Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Total revenues	263,954,000	166,309,000	489,214,000	317,582,000
Total costs and expenses	121,869,000	102,415,000	231,982,000	194,871,000
Income (loss) before income taxes	142,085,000	63,894,000	257,232,000	122,711,000
Income tax (expense) benefit	(483,000)	0	(802,000)	0
Equity (deficit) in income of subsidiaries	0	0	0	0
Net Income (loss)	141,602,000	63,894,000	256,430,000	122,711,000
Dividends on preferred stock	0	0	0	0
Accretion on preferred stock	0	0	0	0
Loss on redemption of preferred stock	0	0	0	0
Net Income Attributable to Common Shareholders	141,602,000	63,894,000	256,430,000	122,711,000
Combined Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Total revenues	0	0	0	0
Total costs and expenses	0	0	0	0
Income (loss) before income taxes	0	0	0	0
Income tax (expense) benefit	0	0	0	0
Equity (deficit) in income of subsidiaries	0	0	0	0
Net Income (loss)	0	0	0	0
Dividends on preferred stock	0	0	0	0
Accretion on preferred stock	0	0	0	0
Loss on redemption of preferred stock	0	0	0	0
Net Income Attributable to Common Shareholders	$ 0	$ 0	$ 0	$ 0

Condensed Consolidating Finan73

Condensed Consolidating Financial Information (Schedule Of Condensed Consolidating Statement Of Cash Flows) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	$ 275,872	$ 179,155
Net cash provided by (used in) investing activities	(85,946)	(366,436)
Net cash provided by (used in) financing activities	(197,367)	185,315
Net Decrease in Cash and Cash Equivalents	(7,441)	(1,966)
Cash and Cash Equivalents, Beginning of Period	9,540	4,194
Cash and Cash Equivalents, End of Period	2,099	2,228
Eliminations [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	0	0
Net cash provided by (used in) investing activities	(349,826)	108,231
Net cash provided by (used in) financing activities	349,826	(108,231)
Net Decrease in Cash and Cash Equivalents	0	0
Cash and Cash Equivalents, Beginning of Period	0	0
Cash and Cash Equivalents, End of Period	0	0
Parent Company [Member] | Reportable Legal Entities [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	(158,309)	(77,501)
Net cash provided by (used in) investing activities	348,235	(109,780)
Net cash provided by (used in) financing activities	(197,367)	185,315
Net Decrease in Cash and Cash Equivalents	(7,441)	(1,966)
Cash and Cash Equivalents, Beginning of Period	9,540	4,194
Cash and Cash Equivalents, End of Period	2,099	2,228
Combined Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	434,181	256,656
Net cash provided by (used in) investing activities	(84,355)	(364,887)
Net cash provided by (used in) financing activities	(349,826)	108,231
Net Decrease in Cash and Cash Equivalents	0	0
Cash and Cash Equivalents, Beginning of Period	0	0
Cash and Cash Equivalents, End of Period	0	0
Combined Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	0	0
Net cash provided by (used in) investing activities	0	0
Net cash provided by (used in) financing activities	0	0
Net Decrease in Cash and Cash Equivalents	0	0
Cash and Cash Equivalents, Beginning of Period	0	0
Cash and Cash Equivalents, End of Period	$ 0	$ 0

Supplemental Cash Flow Inform74

Supplemental Cash Flow Information (Supplemental Cash Flow Disclosures) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Supplemental Cash Flow Elements [Abstract]
Interest Paid, Net	$ 29,853	$ 39,603
Change in capital expenditure payables and accruals	35,543	48,395
Contingent Consideration, Liability, Acquisition Date Fair Value	$ (7,880)	$ 0

Subsequent Events (Narrative) (

Subsequent Events (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Jun. 30, 2017
Subsequent Event [Line Items]
Proceeds from divestitures of oil and gas properties, net		$ 345,789	$ 18,201
Subsequent Event [Member]
Subsequent Event [Line Items]
Proceeds from divestitures of oil and gas properties, net	$ 31,400

Subsequent Events, Derivative I

Subsequent Events, Derivative Instruments (Schedule of Crude Oil Derivative Positions) (Details) - Crude Oil	Sep. 30, 2018bbl / d$ / bbls	Jun. 30, 2018bbl / d$ / bbls
Call Option | FY 2019
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d		3,875
Weighted Average Ceiling Price ($/Bbls)		73.66
Three-way Collars | FY 2019
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d		15,000
Weighted Average Sub-Floor Price ($/Bbls)		41
Weighted Average Floor Price ($/Bbls)		49.72
Weighted Average Ceiling Price ($/Bbls)		62.48
Subsequent Event [Member] | Basis Swaps | FY 2019
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	3,000
Weighted Average Fixed Price ($/Bbl)	4.50
Subsequent Event [Member] | Basis Swaps | Q1 2019
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	2,500
Weighted Average Fixed Price ($/Bbl)	6.94
Subsequent Event [Member] | Basis Swaps | Q2 2019
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	3,000
Weighted Average Fixed Price ($/Bbl)	6.94
Subsequent Event [Member] | Basis Swaps | Q3 2019
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	3,500
Weighted Average Fixed Price ($/Bbl)	6.94
Subsequent Event [Member] | Basis Swaps | Q4 2019
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	5,000
Weighted Average Fixed Price ($/Bbl)	4
Subsequent Event [Member] | Basis Swaps | Derivative Positions, January to March Two Thousand Twenty [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	1,000
Weighted Average Fixed Price ($/Bbl)	1.90
Subsequent Event [Member] | Basis Swaps | Derivative Positions, April to June Two Thousand Twenty [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	13,000
Weighted Average Fixed Price ($/Bbl)	1.32
Subsequent Event [Member] | Basis Swaps | Derivative Positions, July to September Two Thousand Twenty [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	13,000
Weighted Average Fixed Price ($/Bbl)	1.13
Subsequent Event [Member] | Basis Swaps | Derivative Positions, October to December Two Thousand Twenty [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	13,000
Weighted Average Fixed Price ($/Bbl)	0.81