Carrizo Oil & Gas (CRZO) 10-Q 9 May 18 2018 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2018	Apr. 30, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
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		82,067,457

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 4,885,000	$ 9,540,000
Accounts receivable, net	98,788,000	107,441,000
Other current assets	15,528,000	5,897,000
Total current assets	119,201,000	122,878,000
Oil and gas properties, full cost method
Proved properties, net	1,772,927,000	1,965,347,000
Unproved properties, not being amortized	617,754,000	660,287,000
Other property and equipment, net	10,304,000	10,176,000
Total property and equipment, net	2,400,985,000	2,635,810,000
Other assets	18,271,000	19,616,000
Total Assets	2,538,457,000	2,778,304,000
Current liabilities
Accounts payable	106,328,000	74,558,000
Revenues and royalties payable	47,231,000	52,154,000
Accrued capital expenditures	93,531,000	119,452,000
Accrued interest	23,737,000	28,362,000
Derivative liabilities	115,259,000	57,121,000
Other current liabilities	45,495,000	41,175,000
Total current liabilities	431,581,000	372,822,000
Long-term debt	1,442,898,000	1,629,209,000
Asset retirement obligations	15,518,000	23,497,000
Derivative liabilities, noncurrent	70,852,000	112,332,000
Deferred income tax liabilities, noncurrent	3,828,000	3,635,000
Other liabilities	10,381,000	51,650,000
Liabilities	1,975,058,000	2,193,145,000
Commitments and contingencies
Preferred stock, $0.01 par value, 10,000,000 shares authorized; 200,000 issued and outstanding as of March 31, 2018 and 250,000 issued and outstanding as of December 31, 2017	172,118,000	214,262,000
Shareholders’ equity
Common stock, $0.01 par value, 180,000,000 shares authorized; 82,065,561 issued and outstanding as of March 31, 2018 and 81,454,621 issued and outstanding as of December 31, 2017	821,000	815,000
Additional paid-in capital	1,918,942,000	1,926,056,000
Accumulated deficit	(1,528,482,000)	(1,555,974,000)
Total shareholders’ equity	391,281,000	370,897,000
Total Liabilities and Shareholders’ Equity	$ 2,538,457,000	$ 2,778,304,000

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 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)	82,065,561	81,454,621
Common stock, shares outstanding (in shares)	82,065,561	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
	Mar. 31, 2018	Mar. 31, 2017
Crude oil revenues	$ 194,919	$ 128,092
Natural gas liquids revenues	16,902	7,425
Natural gas revenues	13,459	15,838
Total revenues	225,280	151,355
Costs and Expenses
Lease operating	39,273	29,845
Production taxes	10,575	6,208
Ad valorem taxes	1,973	2,967
Depreciation, depletion and amortization	64,467	54,382
General and administrative, net	27,292	21,703
(Gain) loss on derivatives, net	29,596	(25,316)
Interest expense, net	15,517	20,571
Loss on extinguishment of debt	8,676	0
Other expense, net	100	974
Total Costs and Expenses	197,469	111,334
Income Before Income Taxes	27,811	40,021
Income tax expense	(319)	0
Net Income (loss)	27,492	40,021
Dividends on preferred stock	(4,863)	0
Accretion on preferred stock	(753)	0
Loss on redemption of preferred stock	(7,133)	0
Net Income Attributable to Common Shareholders	$ 14,743	$ 40,021
Net Income Attributable to Common Shareholders Per Common Share
Income (loss) per share, basic (in dollars per share)	$ 0.18	$ 0.61
Income (loss) per share, diluted (in dollars per share)	$ 0.18	$ 0.61
Weighted Average Common Shares Outstanding
Basic (in shares)	81,542	65,188
Diluted (in shares)	82,578	65,778

Consolidated Statements Of Shar

Consolidated Statements Of Shareholders' Equity - 3 months ended Mar. 31, 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	5,647		5,647
Issuance of common stock upon grants of restricted stock awards and vestings of restricted stock units and performance shares	(6)	$ 6	(12)
Issuance of common stock upon grants of restricted stock awards, net of forfeitures, and vestings of restricted stock units and performance shares, shares		610,940
Payment of dividends on preferred stock	(4,863)		(4,863)
Accretion on preferred stock	(753)		(753)
Loss on redemption of preferred stock	(7,133)		(7,133)
Net Income (loss)	27,492			27,492
BALANCE at Mar. 31, 2018	$ 391,281	$ 821	$ 1,918,942	$ (1,528,482)
BALANCE, shares at Mar. 31, 2018		82,065,561

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net income (loss)	$ 27,492	$ 40,021
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation, depletion and amortization	64,467	54,382
(Gain) loss on derivatives, net	29,596	(25,316)
Cash (paid) received for derivative settlements, net	(14,365)	1,519
Loss on extinguishment of debt	8,676	0
Stock-based compensation expense, net	3,518	2,014
Deferred income taxes	193	0
Non-cash interest expense, net	662	1,091
Other, net	(2,689)	1,620
Changes in components of working capital and other assets and liabilities-
Accounts receivable	10,738	(2,749)
Accounts payable	15,526	6,661
Accrued liabilities	(4,317)	(2,154)
Other assets and liabilities, net	(773)	(681)
Net cash provided by operating activities	138,724	76,408
Cash Flows From Investing Activities
Capital expenditures	(234,685)	(123,749)
Acquisitions of oil and gas properties	0	(7,032)
Proceeds from divestitures of oil and gas properties, net	342,359	17,372
Other, net	(87)	(417)
Net cash provided by (used in) investing activities	107,587	(113,826)
Cash Flows From Financing Activities
Redemption of senior notes	(326,010)	0
Redemption of preferred stock	(50,030)	0
Borrowings under credit agreement	694,260	280,504
Repayments of borrowings under credit agreement	(563,860)	(244,504)
Payments of debt issuance costs	(150)	(50)
Payment of dividends on preferred stock	(4,863)	0
Other, net	(313)	(335)
Net cash provided by (used in) financing activities	(250,966)	35,615
Net Decrease in Cash and Cash Equivalents	(4,655)	(1,803)
Cash and Cash Equivalents, Beginning of Period	9,540	4,194
Cash and Cash Equivalents, End of Period	$ 4,885	$ 2,391

Nature Of Operations

Nature Of Operations	3 Months Ended
	Mar. 31, 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 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	3 Months Ended
	Mar. 31, 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 months ended March 31, 207 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 table below summarizes the impact of adoption for the three months ended March 31, 2018: Three Months Ended March 31, 2018 Under ASC 606 Under ASC 605 Increase % Increase (In thousands) Revenues Crude oil $194,919 $194,794 $125 0.1 % Natural gas liquids 16,902 16,096 806 5.0 % Natural gas 13,459 12,887 572 4.4 % Total revenues 225,280 223,777 1,503 0.7 % Costs and Expenses Lease operating 39,273 37,770 1,503 4.0 % Income Before Income Taxes $27,811 $27,811 $— — % 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 March 31, 2018 and December 31, 2017, receivables from contracts with customers were $66.3 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, (ii) increases in depreciation, depletion and amortization and interest expense, (iii) decreases in lease operating and general and administrative expense and (iv) additional disclosures. The Company plans to adopt the guidance on the effective date of January 1, 2019. 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 2018 2017 (In thousands, except per share amounts) Net Income Attributable to Common Shareholders $14,743 $40,021 Basic weighted average common shares outstanding 81,542 65,188 Effect of dilutive instruments 1,036 590 Diluted weighted average common shares outstanding 82,578 65,778 Net Income Attributable to Common Shareholders Per Common Share Basic $0.18 $0.61 Diluted $0.18 $0.61 The table below presents the weighted average dilutive and anti-dilutive securities outstanding for the periods presented which consisted of unvested restricted stock awards and units, unvested performance shares and exercisable common stock warrants: Three Months Ended 2018 2017 (In thousands) Dilutive 1,036 590 Anti-dilutive 98 5

Acquisitions and Divestitures

Acquisitions and Divestitures	3 Months Ended
	Mar. 31, 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 net proceeds of $679.8 million (the “ExL Acquisition”). The Company also agreed to pay an additional $50.0 million per year if crude oil prices exceed specific thresholds for each of the years of 2018 through 2021 with a cap of $125.0 million as described in “Note 3. Acquisitions and Divestitures of Oil and Gas Properties” of the Company’s 2017 Annual Report (the “Contingent ExL Consideration”). The Company determined that the Contingent ExL Consideration is an embedded derivative and has reflected the liability at fair value in both current and non-current “Derivative liabilities” in the consolidated balance sheets. The total fair value of the Contingent ExL Consideration as of March 31, 2018 and December 31, 2017 was $91.5 million and $85.6 million , respectively. See “Note 10. Derivative Instruments” and “Note 11. Fair Value Measurements” for further details. The contingent consideration, if paid, will be recognized as a reduction of the fair value liability in the consolidated balance sheets. The ExL Acquisition was accounted for as a business combination, therefore, the purchase price was allocated to the assets acquired and the liabilities assumed based on their estimated acquisition date fair values based on then currently available information as disclosed in “Note 3. Acquisitions and Divestitures of Oil and Gas Properties” of the Company’s 2017 Annual Report. Included in the consolidated statements of income for the three months ended March 31, 2018 are total revenues of $43.5 million and net income attributable to common shareholders of $34.8 million from the ExL Acquisition. Divestitures Niobrara. On January 19, 2018, the Company closed on its sale of substantially all of its assets in the Niobrara Formation for estimated aggregate net proceeds of $132.3 million , subject to post-closing adjustments. The estimated aggregate net proceeds were recognized as a reduction of proved oil and gas properties. The Company could also receive contingent consideration of $5.0 million per year if crude oil prices exceed specific thresholds for each of the years of 2018 through 2020 as described in “Note 3. Acquisitions and Divestitures of Oil and Gas Properties” of the Company’s 2017 Annual Report (the “Contingent Niobrara Consideration”). The Company determined that the Contingent Niobrara Consideration is an embedded derivative and has reflected the asset at fair value in current and non-current “Other assets” in the consolidated balance sheets. The total fair value of the Contingent Niobrara Consideration as of March 31, 2018 and January 19, 2018 was $8.3 million and $7.9 million , respectively. See “Note 10. Derivative Instruments” and “Note 11. Fair Value Measurements” for further details. The contingent consideration, if received, will be recognized as a reduction of the fair value asset in the consolidated balance sheets. Eagle Ford. On January 31, 2018, the Company closed on its sale of a portion of its assets in the Eagle Ford Shale to EP Energy E&P Company, L.P. for estimated aggregate net proceeds of $247.1 million , subject to post-closing adjustments. The estimated aggregate net proceeds were recognized as a reduction of proved oil and gas properties. Utica. On November 15, 2017, the Company closed on its sale of substantially all of its assets in the Utica Shale for aggregate net proceeds of $63.1 million . The Company could also receive contingent consideration of $5.0 million per year if crude oil prices exceed specific thresholds for each of the years of 2018 through 2020 as described in “Note 3. Acquisitions and Divestitures of Oil and Gas Properties” of the Company’s 2017 Annual Report (the “Contingent Utica Consideration”). The Company determined that the Contingent Utica Consideration is an embedded derivative and has reflected the asset at fair value in current and non-current “Other assets” in the consolidated balance sheets. The total fair value of the Contingent Utica Consideration as of March 31, 2018 and December 31, 2017 was $9.0 million and $8.0 million , respectively. See “Note 10. Derivative Instruments” and “Note 11. Fair Value Measurements” for further details. The contingent consideration, if received, will be recognized as a reduction of the fair value asset in the consolidated balance sheets. Marcellus. On November 21, 2017, the Company closed on its sale of substantially all of its assets in the Marcellus Shale for aggregate net proceeds of $73.9 million . The Company could also receive contingent consideration of $3.0 million per year if natural gas prices exceed specific thresholds for each of the years of 2018 through 2020 with a cap of $7.5 million as described in “Note 3. Acquisitions and Divestitures of Oil and Gas Properties” of the Company’s 2017 Annual Report (the “Contingent Marcellus Consideration”). The Company determined that the Contingent Marcellus Consideration is an embedded derivative and has reflected the asset at fair value in current and non-current “Other assets” in the consolidated balance sheets. The total fair value of the Contingent Marcellus Consideration as of March 31, 2018 and December 31, 2017 was $1.7 million and $2.2 million , respectively. See “Note 10. Derivative Instruments” and “Note 11. Fair Value Measurements” for further details. The contingent consideration, if received, will be recognized as a reduction of the fair value asset in the consolidated balance sheets.

Property And Equipment, Net

Property And Equipment, Net	3 Months Ended
	Mar. 31, 2018
Property, Plant and Equipment [Abstract]
Property And Equipment, Net	4. Property and Equipment, Net As of March 31, 2018 and December 31, 2017 , total property and equipment, net consisted of the following: March 31, December 31, (In thousands) Oil and gas properties, full cost method Proved properties $5,486,064 $5,615,153 Accumulated depreciation, depletion and amortization and impairments (3,713,137 ) (3,649,806 ) Proved properties, net 1,772,927 1,965,347 Unproved properties, not being amortized Unevaluated leasehold and seismic costs 564,984 612,589 Capitalized interest 52,770 47,698 Total unproved properties, not being amortized 617,754 660,287 Other property and equipment 26,332 25,625 Accumulated depreciation (16,028 ) (15,449 ) Other property and equipment, net 10,304 10,176 Total property and equipment, net $2,400,985 $2,635,810 Average depreciation, depletion and amortization (“DD&A”) per Boe of proved properties was $13.73 and $12.69 for the three months ended March 31, 2018 and 2017 . The Company capitalized internal costs of employee compensation and benefits, including stock-based compensation, directly associated with acquisition, exploration and development activities totaling $6.6 million and $5.4 million for the three months ended March 31, 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 $10.4 million and $3.8 million for the three months ended March 31, 2018 and 2017 .

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 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 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% and 35% for the three months ended March 31, 2018 and 2017, respectively, to income before income taxes as follows: Three Months Ended 2018 2017 (In thousands) Income before income taxes $27,811 $40,021 Income tax expense at the statutory rate (5,840 ) (14,007 ) State income tax expense, net of U.S. federal income taxes (319 ) (710 ) Tax shortfalls from stock-based compensation expense (2,526 ) (2,592 ) Decrease in deferred tax assets valuation allowance 8,401 17,369 Other (35 ) (60 ) Income tax expense ($319 ) $— 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 Shales in the fourth quarter of 2017 and in the Niobrara Formation 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, as well as current period activity, the Company recorded state current and deferred income tax expense of $0.3 million primarily associated with the future Texas deferred tax liabilities. 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 federal statutory corporate income tax rate to 21% from 35% beginning January 1, 2018. Due to the uncertainty or diversity in views about 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 its 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 March 31, 2018 , the Company had not made any changes to the provisional estimates in its Consolidated Financial Statements included in the 2017 Annual Report. 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 continues to analyze the effects of the Act in its consolidated financial statements and operations. Deferred Tax Assets Valuation Allowance Deferred tax assets are recorded for net operating losses and temporary differences between the book and tax basis of assets and liabilities expected to produce tax deductions in future periods. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those deferred tax assets would be deductible. The Company assesses the realizability of its deferred tax assets on a quarterly basis by considering whether it is more likely than not that all or a portion of the deferred tax assets will not be realized. The Company considers all available evidence (both positive and negative) when determining whether a valuation allowance is required. In making this assessment, the Company evaluated possible sources of taxable income that may be available to realize the deferred tax assets, including projected future taxable income, the reversal of existing temporary differences, taxable income in carryback years and available tax planning strategies. A significant item of objective negative evidence considered was the cumulative historical three year pre-tax loss and a net deferred tax asset position at March 31, 2018 , driven primarily by the impairments of proved oil and gas properties recognized beginning in the third quarter of 2015 and continuing through the third quarter of 2016, which limits the ability to consider other subjective evidence such as the Company’s potential for future growth. Beginning in the third quarter of 2015, and continuing through the first quarter of 2018, the Company concluded that it was more likely than not the deferred tax assets will not be realized. As a result, at the end of each quarter, including March 31, 2018 , the Company determined a valuation allowance was required. For the three months ended March 31, 2018 , the Company reduced the valuation allowance by $8.4 million due to a partial release as a result of current period activity. After the impact of the partial release, the valuation allowance as of March 31, 2018 was $324.6 million . For the three months ended March 31, 2017 , as a result of adopting Accounting Standards Update (“ASU”) No. 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting (“ASU 2016-09”), the Company recognized previously unrecognized windfall tax benefits which resulted in a cumulative-effect adjustment to retained earnings of approximately $15.7 million . This adjustment increased deferred tax assets, which in turn increased the valuation allowance by the same amount as of the beginning of 2017, resulting in a net cumulative-effect adjustment to retained earnings of zero . This increase in the valuation allowance was more than offset by a partial release of $17.4 million as a result of activity during the first quarter of 2017.

Long-Term Debt

Long-Term Debt	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Debt	6. Long-Term Debt Long-term debt consisted of the following as of March 31, 2018 and December 31, 2017 : March 31, December 31, (In thousands) Senior Secured Revolving Credit Facility due 2022 $421,700 $291,300 7.50% Senior Notes due 2020 130,000 450,000 Unamortized premium for 7.50% Senior Notes 153 579 Unamortized debt issuance costs for 7.50% Senior Notes (1,206 ) (4,492 ) 6.25% Senior Notes due 2023 650,000 650,000 Unamortized debt issuance costs for 6.25% Senior Notes (7,884 ) (8,208 ) 8.25% Senior Notes due 2025 250,000 250,000 Unamortized debt issuance costs for 8.25% Senior Notes (4,290 ) (4,395 ) Other long-term debt due 2028 4,425 4,425 Long-term debt $1,442,898 $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 March 31, 2018 , had a borrowing base of $830.0 million , with an elected commitment amount of $800.0 million , and $421.7 million of borrowings outstanding at a weighted average interest rate of 4.24% . As of March 31, 2018 , the Company had no letters of credit outstanding. 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 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 . See “Note 14. Subsequent Events” for details of the twelfth amendment that was entered into in May 2018. 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 and Letters of Credit to Lender Commitments Applicable Margin for Base Rate Loans Applicable Margin for Eurodollar Loans Commitment Fee Less than 25% 1.00% 2.00% 0.375% Greater than or equal to 25% but less than 50% 1.25% 2.25% 0.375% Greater than or equal to 50% but less than 75% 1.50% 2.50% 0.500% Greater than or equal to 75% but less than 90% 1.75% 2.75% 0.500% Greater than or equal to 90% 2.00% 3.00% 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 for the fiscal quarter ended March 31, 2018 is calculated based on an annualized average of the last three fiscal quarters, and EBITDA for fiscal quarters ending thereafter will be calculated based on the last four fiscal quarters, in each case 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 March 31, 2018 , the ratio of Total Debt to EBITDA was 2.60 to 1.00 and the Current Ratio was 1.52 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 On January 19, 2018, the Company delivered a notice of redemption to the trustee for its 7.50% Senior Notes to call for redemption on February 18, 2018, $100.0 million aggregate principal amount of the outstanding 7.50% Senior Notes. On February 20, 2018, the Company paid an aggregate redemption price of $105.1 million , which included a redemption premium of $1.9 million as well as accrued and unpaid interest of $3.2 million from the last interest payment date up to, but not including, the redemption date. As a result of the redemption of $100.0 million of the 7.50% Senior Notes, the Company recorded a loss on extinguishment of debt of $2.7 million , which includes the redemption premium paid to redeem the notes and non-cash charges of $0.8 million attributable to the write-off of unamortized premium and debt issuance costs associated with the 7.50% Senior Notes. On January 31, 2018, the Company delivered a notice of redemption to the trustee for its 7.50% Senior Notes to call for redemption on March 2, 2018, $220.0 million aggregate principal amount of the outstanding 7.50% Senior Notes. On March 2, 2018, the Company paid an aggregate redemption price of $231.8 million , which includes a redemption premium of $4.1 million as well as accrued and unpaid interest of $7.7 million from the last interest payment date up to, but not including, the redemption date. As a result of the redemption of $220.0 million of the 7.50% Senior Notes, the Company recorded a loss on extinguishment of debt of $6.0 million , which includes the redemption premium paid to redeem the notes and non-cash charges of $1.9 million attributable to the write-off of unamortized premium and debt issuance costs associated with the 7.50% Senior Notes.

Commitments And Contingencies

Commitments And Contingencies	3 Months Ended
	Mar. 31, 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	3 Months Ended
	Mar. 31, 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 Company used the net proceeds of approximately $236.4 million , net of issuance costs to fund a portion of the purchase price for the ExL Acquisition and for general corporate purposes. 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 dividend declared by the Company’s Board of Directors and paid in respect of a quarter ending: Period Percentage On or after December 15, 2017 and on or prior to 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. On January 19, 2018, the Company provided a notice to be delivered to the holders of its Preferred Stock under which it called for redemption of 50,000 shares of Preferred Stock, representing 20% of the issued and outstanding Preferred Stock, on January 24, 2018. The Company paid $50.5 million on January 24, 2018 upon redemption, 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 further details. As a result of the redemption, the Company recorded a loss on redemption of preferred stock of $7.1 million , which is presented with the Preferred Stock dividends and accretion in the consolidated statements of income. This loss was calculated as the difference between the consideration transferred to the holders of the Preferred Stock, excluding accrued and unpaid dividends, of $50.0 million and 20% of the carrying value of the Preferred Stock on the date of redemption plus any direct costs incurred as a result of the redemption. 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 and is subject to accretion from its relative fair value at the issuance date to the redemption value using the effective interest method. The Company reassesses the presentation of the Preferred Stock in its consolidated balance sheets on a quarterly basis. The table below summarizes Preferred Stock activity for the three months ended March 31, 2018 : March 31, 2018 For the Three Months Ended March 31, 2018 Preferred Stock, beginning of period $214,262 Redemption of preferred stock (42,897 ) Accretion of discount on Preferred Stock 753 Preferred Stock, end of period $172,118 Preferred Stock Dividends and Accretion For the three months ended March 31, 2018 , the Company declared and paid $4.9 million of dividends in cash. On January 24, 2018, the Company paid $0.5 million of dividends to the holders of record of the Preferred Stock which was redeemed, as described above. Additionally, the Company paid $4.4 million of dividends to the holders of record on March 15, 2018. For the three months ended March 31, 2018 , the Company recorded accretion of the Preferred Stock of $0.8 million , which is presented with the dividends in the consolidated statements of income.

Shareholders' Equity and Stock

Shareholders' Equity and Stock Incentive Plans	3 Months Ended
	Mar. 31, 2018
Shareholders' Equity and Stock Incentive Plans [Abstract]
Shareholders' Equity and Share-based Payments	9. Shareholders’ Equity and Stock-Based Compensation Stock-Based Compensation As of March 31, 2018 , there were 318,109 common shares remaining available for grant under the 2017 Incentive Plan of Carrizo Oil & Gas, Inc. (the “2017 Incentive Plan”). Each restricted stock award, restricted stock unit, or performance share granted under the 2017 Incentive Plan counts as 1.35 shares while a stock option or stock-settled stock appreciation right granted under the 2017 Incentive Plan counts as 1.00 share against the number of common shares available for grant under the 2017 Incentive Plan. Restricted Stock Awards and Units. Restricted stock awards can be granted to employees and independent contractors and restricted stock units can be granted to employees, independent contractors, and non-employee directors. As of March 31, 2018 , unrecognized compensation costs related to unvested restricted stock awards and units was $35.0 million and will be recognized over a weighted average period of 2.4 years. The table below summarizes restricted stock award and unit activity for the three months ended March 31, 2018 : Restricted Stock Awards and Units Weighted Average Grant Date Fair Value For the Three Months Ended March 31, 2018 Unvested restricted stock awards and units, beginning of period 1,482,655 $28.07 Granted 1,347,165 $14.68 Vested (564,912 ) $31.87 Forfeited (1,078 ) $29.61 Unvested restricted stock awards and units, end of period 2,263,830 $19.15 During the first quarter of 2018, the Company granted 1,343,412 restricted stock units to employees and independent contractors with a grant date fair value of $19.7 million as part of its annual grant of long-term equity incentive awards. These restricted stock units will vest ratably over a three -year period. Stock Appreciation Rights (“SARs”). SARs can be granted to employees and independent contractors under the Carrizo Oil & Gas, Inc. Cash-Settled Stock Appreciation Rights Plan (“Cash SAR Plan”) and employees, independent contractors, and non-employee directors under the 2017 Incentive Plan. SARs granted under the Cash SAR Plan may only be settled in cash, while SARs granted under the 2017 Incentive Plan can be settled in shares of common stock or cash, at the option of the Company. Outstanding SARs that have been granted under the 2017 Incentive Plan have been deemed to be settled in cash, therefore, all outstanding SARs will be settled in cash. The grant date fair value of SARs is calculated using the Black-Scholes-Merton option pricing model. The liability for SARs as of March 31, 2018 was $2.9 million , of which $0.1 million was classified as “Other current liabilities,” with the remaining $2.8 million classified as “Other 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 $5.8 million as of March 31, 2018 , and will be recognized over a weighted average period of 2.8 years. The table below summarizes the activity for SARs for the three months ended March 31, 2018 : Stock Appreciation Rights Weighted Average Exercise Prices Weighted Average Remaining Life (In years) Aggregate Intrinsic Value (In millions) Aggregate Intrinsic Value of Exercises (In millions) For the Three Months Ended March 31, 2018 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 5.1 $0.7 Vested, end of period 543,018 $27.18 Vested and exercisable, end of period — $27.18 3.3 $— During the first quarter of 2018, the Company granted 616,686 SARs under the 2017 Incentive Plan with a grant date fair value of $4.9 million to certain employees and independent contractors as part of its annual grant of long-term equity incentive awards. These SARs will vest ratably over a three -year period and expire approximately seven years from the grant date. The following table summarizes the assumptions used to calculate the grant date fair value of SARs granted during the three months ended March 31, 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. The Company can grant performance shares to employees, independent contractors, and non-employee directors, where each performance share represents the right to receive one share of common stock. 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. The grant date fair value of the performance awards is calculated using a Monte Carlo simulation. As of March 31, 2018 , unrecognized compensation costs related to unvested performance shares was $3.3 million and will be recognized over a weighted average period of 2.4 years. The table below summarizes performance share activity for the three months ended March 31, 2018 : Target Performance Shares (1) Weighted Average Grant Date Fair Value For the Three Months Ended March 31, 2018 Unvested performance shares, beginning of period 144,955 $47.14 Granted 93,771 $19.09 Vested (49,458 ) $65.51 Forfeited (7,059 ) $65.51 Unvested performance shares, end of period 182,209 $27.01 (1) The number of shares of common stock issued upon vesting may vary from the number of target performance shares depending on the Company ’ s final TSR ranking for the approximate three-year performance period. During the first quarter of 2018, the Company granted 93,771 target performance shares to certain employees and independent contractors with a grant date fair value of $1.8 million as part of its annual grant of long-term equity incentive awards. Also during the first quarter of 2018, the Company issued 49,458 shares of common stock for 56,517 target performance shares that vested during the first quarter of 2018 with a multiplier of 88% based on the Company’s final TSR ranking during the performance period. The following table summarizes the assumptions used to calculate the grant date fair value of the performance shares granted during the three months ended March 31, 2018 : Grant Date Fair Value Assumptions Number of simulations 500,000 Expected term (in years) 3.00 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 periods indicated: Three Months Ended 2018 2017 (In thousands) Restricted stock awards and units $5,084 $5,849 SARs (1,415 ) (3,686 ) Performance shares 557 706 4,226 2,869 Less: amounts capitalized to oil and gas properties (708 ) (855 ) Total stock-based compensation expense, net $3,518 $2,014

Derivative Instruments

Derivative Instruments	3 Months Ended
	Mar. 31, 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 crude oil, NGL, and natural gas production and thereby achieve a more predictable level of cash flows to support the Company’s drilling, completion, and infrastructure capital expenditure program. The Company does not enter into derivative instruments for speculative or trading purposes. The Company’s commodity derivative instruments consist of fixed price swaps, basis swaps, three-way collars and purchased and sold call options, which are described below. Fixed Price Swaps: The Company receives a fixed price and pays a variable market price to the counterparties over specified periods for contracted volumes. Basis Swaps: The Company receives a variable NYMEX settlement price, plus or minus a fixed differential price, and pays a variable published index price to the counterparties 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 market 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 market price, respectively. If the market price is below the fixed sub-floor price, the Company receives the market price plus the difference between the fixed floor price and the fixed sub-floor price. If the market 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. Sold Call Options : These contracts give the counterparties 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 market price exceeds the fixed price of the call option, the Company pays the counterparty the excess. If the market price settles below the fixed price of the call option, no payment is due from either party. These contracts require the counterparties to pay premiums to the Company that represent the fair value of the call option as of the date of purchase. Purchased Call Options : These contracts give the Company the right, but not the obligation, to buy contracted volumes from the counterparties over specified periods and prices in the future. At settlement, if the market price exceeds the fixed price of the call option, the counterparties pay the Company the excess. If the market 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 counterparties that represent the fair value of the call option as of the date of purchase. All of the Company’s purchased call options were executed contemporaneously with sales of call options to increase the fixed price on a portion of the existing sold call options and therefore are presented on a net basis in the “Net Sold Call Options” table below. Premiums : In order to increase the fixed price on a portion of the Company’s existing sold call options, as mentioned above, the Company incurred premiums on its purchased call options. Additionally, the Company has incurred premiums on certain of its three-way collars in order to obtain a higher floor price and/or ceiling price. The payment of premiums associated with the Company’s purchased call options and certain of the three-way collars are deferred until the applicable contracts settle on a monthly basis. When the Company has entered into three-way collars which span multiple years, the Company has elected to defer payment of certain of the premiums until the final year’s contracts settle on a monthly basis. The following table sets forth a summary of the Company’s outstanding crude oil derivative positions at weighted average contract prices as of March 31, 2018 : Period Type of Contract Index Volumes (Bbls/d) Fixed Price ($/Bbl) Sub-Floor Price ($/Bbl) Floor Price ($/Bbl) Ceiling Price ($/Bbl) 2018 Q2 - Q4 2018 Fixed Price Swaps NYMEX WTI 6,000 $49.55 $— $— $— Q2 - Q4 2018 Basis Swaps (1) 6,000 2.91 — — — Q2 - Q4 2018 Basis Swaps (2) 6,000 (0.10 ) — — — Q2 - Q4 2018 Three-Way Collars NYMEX WTI 24,000 — 39.38 49.06 60.14 Q2 - Q4 2018 Net Sold Call Options NYMEX WTI 3,388 — — — 71.33 2019 Q1 - Q2 2019 Basis Swaps (2) 500 (2.99 ) — — — Q1 - Q4 2019 Three-Way Collars NYMEX WTI 12,000 — 40.00 48.40 60.29 Q1 - Q4 2019 Net Sold Call Options NYMEX WTI 3,875 — — — 73.66 2020 Q1 - Q4 2020 Net Sold Call Options NYMEX WTI 4,575 — — — 75.98 (1) The Company has entered into crude oil basis swaps in order to fix the differential between LLS-Cushing. The weighted average price differential represents the amount of premium to Cushing for the volumes presented in the table above. (2) The Company has entered into crude oil basis swaps in order to fix the differential between Midland-Cushing. The weighted average price differential represents the amount of reduction to Cushing for the volumes presented in the table above. The following table sets forth a summary of the Company’s outstanding NGL derivative positions at weighted average contract prices as of March 31, 2018 : Period Type of Contract Index Volumes (Bbls/d) Fixed Price ($/Bbl) 2018 Q2 - Q4 2018 Fixed Price Swaps Ethane - OPIS Mont Belvieu Non-TET 2,200 $12.01 Q2 - Q4 2018 Fixed Price Swaps Propane - OPIS Mont Belvieu Non-TET 1,500 34.23 Q2 - Q4 2018 Fixed Price Swaps Butane - OPIS Mont Belvieu Non-TET 200 38.85 Q2 - Q4 2018 Fixed Price Swaps Isobutane - OPIS Mont Belvieu Non-TET 600 38.98 Q2 - Q4 2018 Fixed Price Swaps Natural Gasoline - OPIS Mont Belvieu Non-TET 600 55.23 The following table sets forth a summary of the Company’s outstanding natural gas derivative positions at weighted average contract prices as of March 31, 2018 : Period Type of Contract Index Volumes (MMBtu/d) Fixed Price ($/Bbl) Ceiling Price ($/Bbl) 2018 Q2 - Q4 2018 Fixed Price Swaps NYMEX HH 25,000 $3.01 $— Q2 - Q4 2018 Sold Call Options NYMEX HH 33,000 — 3.25 2019 Q1 - Q4 2019 Sold Call Options NYMEX HH 33,000 — 3.25 2020 Q1 - Q4 2020 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 fair value derivative asset and liability positions held with that counterparty. The Company nets its 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 derivative instruments who are also lenders under the Company’s credit agreement allow the Company to satisfy any need for margin obligations associated with derivative instruments where the Company is in a net liability position with its counterparties with the collateral securing the credit agreement, thus eliminating the need for independent collateral posting. Counterparties who are not lenders under the Company’s credit agreement can require derivative contracts to be novated to a lender if the net liability position exceeds the Company’s unsecured credit limit with that counterparty and therefore do not require the posting of cash collateral. Because the counterparties have investment grade credit ratings, or the Company has obtained guarantees from the applicable counterparty’s investment grade parent company, 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 derivative instruments. Although the Company does not currently anticipate nonperformance from its counterparties, it continually monitors the credit ratings of its counterparties and its counterparty’s parent company, as applicable. Contingent Consideration As part of the ExL Acquisition in 2017, the Company agreed to the Contingent ExL Consideration that will require payment of $50.0 million per year for each of the years of 2018 through 2021, with a cap of $125.0 million , if the EIA WTI average price is greater than $50.00 per barrel for the respective year. As of March 31, 2018 , the estimated fair value of the Contingent ExL Consideration was $91.5 million . As part of the divestiture of the Company’s Utica assets in 2017, the Company agreed to the Contingent Utica Consideration in which the Company will receive $5.0 million per year for each of the years of 2018 through 2020, if the EIA WTI average price is greater than $50.00 , $53.00 , and $56.00 for the years of 2018, 2019, and 2020, respectively. As of March 31, 2018 , the estimated fair value of the Contingent Utica Consideration was $9.0 million . As part of the divestiture of the Company’s Marcellus assets in 2017, the Company agreed to the Contingent Marcellus Consideration in which the Company will receive $3.0 million per year for each of the years of 2018 through 2020, with a cap of $7.5 million , if the CME HH average price is greater than $3.13 , $3.18 , and $3.30 for the years of 2018, 2019, and 2020, respectively. As of March 31, 2018 , the estimated fair value of the Contingent Marcellus Consideration was $1.7 million . As part of the divestiture of the Company’s Niobrara assets in the first quarter of 2018, the Company agreed to the Contingent Niobrara Consideration in which the Company will receive $5.0 million per year for each of the years of 2018 through 2020, if the EIA WTI average price is above $55.00 for the years of 2018 and 2019 and above $60.00 for 2020. The Company recorded the Contingent Niobrara Consideration at its divestiture date fair value of $7.9 million in the consolidated financial statements. As of March 31, 2018 , the estimated fair value of the Contingent Niobrara Consideration was $8.3 million . The following tables summarize the combined contingent consideration recorded in the consolidated financial statements: Consolidated Balance Sheets March 31, 2018 Other Assets - Other Assets - Derivative Liabilities - Current Derivative Liabilities - (In thousands) Contingent ExL Consideration $— $— ($47,260 ) ($44,195 ) Contingent Utica Consideration 4,685 4,320 — — Contingent Marcellus Consideration 360 1,375 — — Contingent Niobrara Consideration 4,415 3,850 — — Contingent consideration $9,460 $9,545 ($47,260 ) ($44,195 ) Consolidated Balance Sheets December 31, 2017 Other Assets - Current Other Assets - Non-Current Derivative Liabilities - Current Derivative Liabilities - Non-Current (In thousands) Contingent ExL Consideration $— $— $— ($85,625 ) Contingent Utica Consideration — 7,985 — — Contingent Marcellus Consideration — 2,205 — — Contingent Niobrara Consideration — — — — Contingent consideration $— $10,190 $— ($85,625 ) Consolidated Statements of Income Three Months Ended March 31, 2018 (Gain) Loss on Derivatives, Net (In thousands) Contingent ExL Consideration $5,830 Contingent Utica Consideration (1,020 ) Contingent Marcellus Consideration 470 Contingent Niobrara Consideration (385 ) Contingent consideration $4,895 Derivative Assets and Liabilities All 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. The combined derivative instrument fair value assets and liabilities, including deferred premium obligations, recorded in the consolidated balance sheets as of March 31, 2018 and December 31, 2017 are summarized below: March 31, 2018 Gross Amounts Recognized Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts Presented in the Consolidated Balance Sheets (In thousands) Commodity derivative instruments $15,494 ($15,027 ) $467 Deferred premium obligations — — — Contingent consideration 9,460 — 9,460 Other current assets $24,954 ($15,027 ) $9,927 Commodity derivative instruments 9,855 (9,830 ) 25 Deferred premium obligations — — — Contingent consideration 9,545 — 9,545 Other assets-non current $19,400 ($9,830 ) $9,570 Commodity derivative instruments ($73,280 ) $15,027 ($58,253 ) Deferred premium obligations (9,746 ) — (9,746 ) Contingent consideration (47,260 ) — (47,260 ) Derivative liabilities-current ($130,286 ) $15,027 ($115,259 ) Commodity derivative instruments (27,019 ) 9,830 (17,189 ) Deferred premium obligations (9,468 ) — (9,468 ) Contingent consideration (44,195 ) — (44,195 ) Derivative liabilities-non current ($80,682 ) $9,830 ($70,852 ) 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 ) $— Deferred premium obligations — — — Other current assets $4,869 ($4,869 ) $— Commodity derivative instruments 9,505 (9,505 ) — Deferred premium obligations — — — Contingent consideration 10,190 — 10,190 Other assets-non current $19,695 ($9,505 ) $10,190 Commodity derivative instruments ($52,671 ) $4,869 ($47,802 ) Deferred premium obligations (9,319 ) — (9,319 ) Derivative liabilities-current ($61,990 ) $4,869 ($57,121 ) Commodity derivative instruments (24,609 ) 9,505 (15,104 ) Deferred premium obligations (11,603 ) — (11,603 ) Contingent consideration (85,625 ) — (85,625 ) Derivative liabilities-non current ($121,837 ) $9,505 ($112,332 ) See “Note 11. Fair Value Measurements” for additional details 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 and contingent consideration 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 effect of derivative instruments and deferred premium obligations in the consolidated statements of income for the three months ended March 31, 2018 and 2017 is summarized below: Three Months Ended 2018 2017 (In thousands) (Gain) Loss on Derivatives, Net Crude oil $29,511 ($18,480 ) Natural gas liquids (1,765 ) — Natural gas (3,045 ) (6,836 ) Contingent consideration 4,895 — Total (Gain) Loss on Derivatives, Net $29,596 ($25,316 ) Cash Received (Paid) for Derivative Settlements, Net Cash flows are impacted to the extent that settlements under these contracts, including deferred premium obligations paid, result in payments to or receipts from the counterparty 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 acquisition date fair value with any excess classified as cash flows from operating activities. The effect of commodity derivative instruments and deferred premium obligations in the consolidated statements of cash flows for the three months ended March 31, 2018 and 2017 is summarized below: Three Months Ended 2018 2017 (In thousands) Cash Received (Paid) for Derivative Settlements, Net Crude oil ($12,123 ) $3,031 Natural gas liquids (432 ) — Natural gas 52 (1,149 ) Deferred premium obligations paid (1,862 ) (363 ) Total Cash Received (Paid) for Derivative Settlements, Net ($14,365 ) $1,519

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 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 assets and liabilities measured at fair value on a recurring basis as of March 31, 2018 and December 31, 2017 : March 31, 2018 Level 1 Level 2 Level 3 (In thousands) Derivative instrument assets $— $492 $19,005 Derivative instrument liabilities $— ($75,442 ) ($91,455 ) December 31, 2017 Level 1 Level 2 Level 3 (In thousands) Derivative instrument assets $— $— $10,190 Derivative instrument liabilities $— ($62,906 ) ($85,625 ) The derivative 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 derivative assets and the Company’s credit quality for derivative liabilities. The Company typically has numerous hedge positions that span several time periods and often result in both fair value derivative asset and liability positions held with that counterparty. Deferred premium obligations are netted with the fair value 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 derivative 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 three months ended March 31, 2018 and 2017 . Contingent consideration. The fair values of the Contingent ExL Consideration, the Contingent Utica Consideration, the Contingent Marcellus Consideration and the Contingent Niobrara Consideration were determined by a third-party valuation specialist using Monte Carlo simulations including significant inputs such as future commodity prices, volatility factors for the future commodity prices and a risk adjusted discount rate. As some of these assumptions are not observable throughout the full term of the contingent consideration, the contingent consideration was 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 tables present reconciliations of changes in the fair values of the financial assets and liabilities related to the Company’s contingent consideration, which were designated as Level 3 within the valuation hierarchy, for the three months ended March 31, 2018 : Three Months Ended March 31, 2018 (In thousands) Fair value assets, beginning of period $10,190 Recognition of divestiture date fair value 7,880 Gain (loss) on changes in fair value (1) 935 Transfers into (out of) Level 3 — Fair value assets, end of period $19,005 Three Months Ended March 31, 2018 (In thousands) Fair value liability, beginning of period ($85,625 ) Gain (loss) on changes in fair value (1) (5,830 ) Transfers into (out of) Level 3 — Fair value liability, end of period ($91,455 ) (1) Included in “(Gain) loss on derivatives, net” in the consolidated statements of income. See “Note 3. Acquisitions and Divestitures of Oil and Gas Properties” and “Note 10. Derivative Instruments” for further details regarding the contingent consideration. 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, which are designated as Level 1 under the fair value hierarchy. 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, net of unamortized premiums and debt issuance costs, with the fair values measured using quoted secondary market trading prices. March 31, 2018 December 31, 2017 Carrying Amount Fair Value Carrying Amount Fair Value (In thousands) 7.50% Senior Notes due 2020 $128,947 $132,236 $446,087 $459,518 6.25% Senior Notes due 2023 642,116 650,540 641,792 674,375 8.25% Senior Notes due 2025 245,710 262,500 245,605 274,375 Other long-term debt due 2028 4,425 4,348 4,425 4,445

Condensed Consolidating Financi

Condensed Consolidating Financial Information	3 Months Ended
	Mar. 31, 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) March 31, 2018 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Assets Total current assets $3,121,696 $105,225 $— ($3,107,720 ) $119,201 Total property and equipment, net 6,075 2,395,752 3,028 (3,870 ) 2,400,985 Investment in subsidiaries (884,965 ) — — 884,965 — Other assets 8,725 9,546 — — 18,271 Total Assets $2,251,531 $2,510,523 $3,028 ($2,226,625 ) $2,538,457 Liabilities and Shareholders’ Equity Current liabilities $209,448 $3,329,846 $3,028 ($3,110,741 ) $431,581 Long-term liabilities 1,461,955 65,642 — 15,880 1,543,477 Preferred stock 172,118 — — — 172,118 Total shareholders’ equity 408,010 (884,965 ) — 868,236 391,281 Total Liabilities and Shareholders’ Equity $2,251,531 $2,510,523 $3,028 ($2,226,625 ) $2,538,457 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 OPERATIONS (In thousands) (Unaudited) Three Months Ended March 31, 2018 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Total revenues $20 $225,260 $— $— $225,280 Total costs and expenses 87,365 110,113 — (9 ) 197,469 Income (loss) before income taxes (87,345 ) 115,147 — 9 27,811 Income tax benefit — (319 ) — — (319 ) Equity in income of subsidiaries 114,828 — — (114,828 ) — Net income $27,483 $114,828 $— ($114,819 ) $27,492 Dividends on preferred stock (4,863 ) — — — (4,863 ) Accretion on preferred stock (753 ) — — — (753 ) Loss on redemption of preferred stock (7,133 ) — — — (7,133 ) Net income attributable to common shareholders $14,734 $114,828 $— ($114,819 ) $14,743 Three Months Ended March 31, 2017 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Total revenues $82 $151,273 $— $— $151,355 Total costs and expenses 18,868 92,456 — 10 111,334 Loss before income taxes (18,786 ) 58,817 — (10 ) 40,021 Income tax benefit — — — — — Equity in loss of subsidiaries 58,817 — — (58,817 ) — Net loss $40,031 $58,817 $— ($58,827 ) $40,021 Dividends on preferred stock — — — — — Accretion on preferred stock — — — — — Loss on redemption of preferred stock — — — — — Net income attributable to common shareholders $40,031 $58,817 $— ($58,827 ) $40,021 CARRIZO OIL & GAS, INC. CONDENSED CONSOLIDATING STATEMENTS OF INCOME (In thousands) (Unaudited) Three Months Ended March 31, 2018 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Total revenues $20 $225,260 $— $— $225,280 Total costs and expenses 87,365 110,113 — (9 ) 197,469 Income (loss) before income taxes (87,345 ) 115,147 — 9 27,811 Income tax expense — (319 ) — — (319 ) Equity in income of subsidiaries 114,828 — — (114,828 ) — Net income $27,483 $114,828 $— ($114,819 ) $27,492 Dividends on preferred stock (4,863 ) — — — (4,863 ) Accretion on preferred stock (753 ) — — — (753 ) Loss on redemption of preferred stock (7,133 ) — — — (7,133 ) Net income attributable to common shareholders $14,734 $114,828 $— ($114,819 ) $14,743 Three Months Ended March 31, 2017 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Total revenues $82 $151,273 $— $— $151,355 Total costs and expenses 18,868 92,456 — 10 111,334 Income (loss) before income taxes (18,786 ) 58,817 — (10 ) 40,021 Income tax expense — — — — — Equity in income of subsidiaries 58,817 — — (58,817 ) — Net income $40,031 $58,817 $— ($58,827 ) $40,021 Dividends on preferred stock — — — — — Accretion on preferred stock — — — — — Loss on redemption of preferred stock — — — — — Net income attributable to common shareholders $40,031 $58,817 $— ($58,827 ) $40,021 CARRIZO OIL & GAS, INC. CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS (In thousands) (Unaudited) Three Months Ended March 31, 2018 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Net cash provided by (used in) operating activities ($88,377 ) $227,101 $— $— $138,724 Net cash provided by investing activities 334,688 107,862 — (334,963 ) 107,587 Net cash used in financing activities (250,966 ) (334,963 ) — 334,963 (250,966 ) Net decrease in cash and cash equivalents (4,655 ) — — — (4,655 ) Cash and cash equivalents, beginning of period 9,540 — — — 9,540 Cash and cash equivalents, end of period $4,885 $— $— $— $4,885 Three Months Ended March 31, 2017 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Net cash provided by (used in) operating activities ($47,297 ) $123,705 $— $— $76,408 Net cash provided by (used in) investing activities 9,879 (114,212 ) — (9,493 ) (113,826 ) Net cash provided by (used in) financing activities 35,615 (9,493 ) — 9,493 35,615 Net decrease in cash and cash equivalents (1,803 ) — — — (1,803 ) Cash and cash equivalents, beginning of period 4,194 — — — 4,194 Cash and cash equivalents, end of period $2,391 $— $— $— $2,391

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	3 Months Ended
	Mar. 31, 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: Three Months Ended 2018 2017 (In thousands) Supplemental cash flow disclosures: Cash paid for interest, net of amounts capitalized $14,855 $19,480 Non-cash investing activities: Increase (decrease) in capital expenditure payables and accruals ($9,677 ) $28,139 Contingent consideration related to divestitures of oil and gas properties (7,880 ) —

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	14. Subsequent Events Hedging In April 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 ($/Bbl) Sub-Floor Price ($/Bbl) Floor Price ($/Bbl) Ceiling Price ($/Bbl) 2019 Q1 - Q2 2019 Basis Swaps (1) 2,500 ($4.00 ) $— $— $— Q3 - Q4 2019 Basis Swaps (1) 3,000 (4.00 ) — — — Q1 - Q4 2019 Three-Way Collars NYMEX WTI 3,000 — 45.00 55.00 71.21 (1) The Company has entered into crude oil basis swaps in order to fix the differential between Midland-Cushing. The weighted average price differential represents the amount of reduction to Cushing for the volumes presented in the table above. Redemption of Other Long-Term Debt On April 2, 2018, the Company delivered a notice of redemption to the trustee for its 4.375% Convertible Senior Notes due 2028 to call for redemption on May 3, 2018 all of the remaining outstanding convertible senior notes. On May 3, 2018, the Company paid an aggregate redemption price of $4.5 million , which consisted of a redemption price of $4.4 million , equal to 100% of the principal amount of the notes redeemed, plus accrued and unpaid interest of $0.1 million from the last interest payment date up to, but not including, the redemption date. Twelfth Amendment to the Credit Agreement 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 margins applied to 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.

Summary of Significant Accoun21

Summary of Significant Accounting Policies (Policy)	3 Months Ended
	Mar. 31, 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 months ended March 31, 207 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 table below summarizes the impact of adoption for the three months ended March 31, 2018: Three Months Ended March 31, 2018 Under ASC 606 Under ASC 605 Increase % Increase (In thousands) Revenues Crude oil $194,919 $194,794 $125 0.1 % Natural gas liquids 16,902 16,096 806 5.0 % Natural gas 13,459 12,887 572 4.4 % Total revenues 225,280 223,777 1,503 0.7 % Costs and Expenses Lease operating 39,273 37,770 1,503 4.0 % Income Before Income Taxes $27,811 $27,811 $— — % 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 March 31, 2018 and December 31, 2017, receivables from contracts with customers were $66.3 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, (ii) increases in depreciation, depletion and amortization and interest expense, (iii) decreases in lease operating and general and administrative expense and (iv) additional disclosures. The Company plans to adopt the guidance on the effective date of January 1, 2019.

Summary of Significant Accoun22

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]	The table below summarizes the impact of adoption for the three months ended March 31, 2018: Three Months Ended March 31, 2018 Under ASC 606 Under ASC 605 Increase % Increase (In thousands) Revenues Crude oil $194,919 $194,794 $125 0.1 % Natural gas liquids 16,902 16,096 806 5.0 % Natural gas 13,459 12,887 572 4.4 % Total revenues 225,280 223,777 1,503 0.7 % Costs and Expenses Lease operating 39,273 37,770 1,503 4.0 % Income Before Income Taxes $27,811 $27,811 $— — %
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 2018 2017 (In thousands, except per share amounts) Net Income Attributable to Common Shareholders $14,743 $40,021 Basic weighted average common shares outstanding 81,542 65,188 Effect of dilutive instruments 1,036 590 Diluted weighted average common shares outstanding 82,578 65,778 Net Income Attributable to Common Shareholders Per Common Share Basic $0.18 $0.61 Diluted $0.18 $0.61
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The table below presents the weighted average dilutive and anti-dilutive securities outstanding for the periods presented which consisted of unvested restricted stock awards and units, unvested performance shares and exercisable common stock warrants: Three Months Ended 2018 2017 (In thousands) Dilutive 1,036 590 Anti-dilutive 98 5

Property And Equipment, Net (Ta

Property And Equipment, Net (Tables)	3 Months Ended
	Mar. 31, 2018
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	As of March 31, 2018 and December 31, 2017 , total property and equipment, net consisted of the following: March 31, December 31, (In thousands) Oil and gas properties, full cost method Proved properties $5,486,064 $5,615,153 Accumulated depreciation, depletion and amortization and impairments (3,713,137 ) (3,649,806 ) Proved properties, net 1,772,927 1,965,347 Unproved properties, not being amortized Unevaluated leasehold and seismic costs 564,984 612,589 Capitalized interest 52,770 47,698 Total unproved properties, not being amortized 617,754 660,287 Other property and equipment 26,332 25,625 Accumulated depreciation (16,028 ) (15,449 ) Other property and equipment, net 10,304 10,176 Total property and equipment, net $2,400,985 $2,635,810

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 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% and 35% for the three months ended March 31, 2018 and 2017, respectively, to income before income taxes as follows: Three Months Ended 2018 2017 (In thousands) Income before income taxes $27,811 $40,021 Income tax expense at the statutory rate (5,840 ) (14,007 ) State income tax expense, net of U.S. federal income taxes (319 ) (710 ) Tax shortfalls from stock-based compensation expense (2,526 ) (2,592 ) Decrease in deferred tax assets valuation allowance 8,401 17,369 Other (35 ) (60 ) Income tax expense ($319 ) $—

Long-Term Debt (Tables)

Long-Term Debt (Tables)	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	Long-term debt consisted of the following as of March 31, 2018 and December 31, 2017 : March 31, December 31, (In thousands) Senior Secured Revolving Credit Facility due 2022 $421,700 $291,300 7.50% Senior Notes due 2020 130,000 450,000 Unamortized premium for 7.50% Senior Notes 153 579 Unamortized debt issuance costs for 7.50% Senior Notes (1,206 ) (4,492 ) 6.25% Senior Notes due 2023 650,000 650,000 Unamortized debt issuance costs for 6.25% Senior Notes (7,884 ) (8,208 ) 8.25% Senior Notes due 2025 250,000 250,000 Unamortized debt issuance costs for 8.25% Senior Notes (4,290 ) (4,395 ) Other long-term debt due 2028 4,425 4,425 Long-term debt $1,442,898 $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 and Letters of Credit to Lender Commitments Applicable Margin for Base Rate Loans Applicable Margin for Eurodollar Loans Commitment Fee Less than 25% 1.00% 2.00% 0.375% Greater than or equal to 25% but less than 50% 1.25% 2.25% 0.375% Greater than or equal to 50% but less than 75% 1.50% 2.50% 0.500% Greater than or equal to 75% but less than 90% 1.75% 2.75% 0.500% Greater than or equal to 90% 2.00% 3.00% 0.500%

Preferred Stock (Tables)

Preferred Stock (Tables)	3 Months Ended
	Mar. 31, 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 dividend declared by the Company’s Board of Directors and paid in respect of a quarter ending: Period Percentage On or after December 15, 2017 and on or prior to 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 Preferred Stock activity for the three months ended March 31, 2018 : March 31, 2018 For the Three Months Ended March 31, 2018 Preferred Stock, beginning of period $214,262 Redemption of preferred stock (42,897 ) Accretion of discount on Preferred Stock 753 Preferred Stock, end of period $172,118

Shareholders' Equity and Stoc27

Shareholders' Equity and Stock Incentive Plans (Tables)	3 Months Ended
	Mar. 31, 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 three months ended March 31, 2018 : Restricted Stock Awards and Units Weighted Average Grant Date Fair Value For the Three Months Ended March 31, 2018 Unvested restricted stock awards and units, beginning of period 1,482,655 $28.07 Granted 1,347,165 $14.68 Vested (564,912 ) $31.87 Forfeited (1,078 ) $29.61 Unvested restricted stock awards and units, end of period 2,263,830 $19.15
Schedule of Stock Appreciation Rights Award Activity	The table below summarizes the activity for SARs for the three months ended March 31, 2018 : Stock Appreciation Rights Weighted Average Exercise Prices Weighted Average Remaining Life (In years) Aggregate Intrinsic Value (In millions) Aggregate Intrinsic Value of Exercises (In millions) For the Three Months Ended March 31, 2018 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 5.1 $0.7 Vested, end of period 543,018 $27.18 Vested and exercisable, end of period — $27.18 3.3 $—
Schedule of Stock Appreciation Rights Valuation Assumptions	The following table summarizes the assumptions used to calculate the grant date fair value of SARs granted during the three months ended March 31, 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 three months ended March 31, 2018 : Target Performance Shares (1) Weighted Average Grant Date Fair Value For the Three Months Ended March 31, 2018 Unvested performance shares, beginning of period 144,955 $47.14 Granted 93,771 $19.09 Vested (49,458 ) $65.51 Forfeited (7,059 ) $65.51 Unvested performance shares, end of period 182,209 $27.01
Schedule of Performance Share Award Valuation Assumptions	The following table summarizes the assumptions used to calculate the grant date fair value of the performance shares granted during the three months ended March 31, 2018 : Grant Date Fair Value Assumptions Number of simulations 500,000 Expected term (in years) 3.00 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 periods indicated: Three Months Ended 2018 2017 (In thousands) Restricted stock awards and units $5,084 $5,849 SARs (1,415 ) (3,686 ) Performance shares 557 706 4,226 2,869 Less: amounts capitalized to oil and gas properties (708 ) (855 ) Total stock-based compensation expense, net $3,518 $2,014

Derivative Instruments (Tables)

Derivative Instruments (Tables)	3 Months Ended
	Mar. 31, 2018
Derivative [Line Items]
Schedule of Contingent Consideration	The following tables summarize the combined contingent consideration recorded in the consolidated financial statements: Consolidated Balance Sheets March 31, 2018 Other Assets - Other Assets - Derivative Liabilities - Current Derivative Liabilities - (In thousands) Contingent ExL Consideration $— $— ($47,260 ) ($44,195 ) Contingent Utica Consideration 4,685 4,320 — — Contingent Marcellus Consideration 360 1,375 — — Contingent Niobrara Consideration 4,415 3,850 — — Contingent consideration $9,460 $9,545 ($47,260 ) ($44,195 ) Consolidated Balance Sheets December 31, 2017 Other Assets - Current Other Assets - Non-Current Derivative Liabilities - Current Derivative Liabilities - Non-Current (In thousands) Contingent ExL Consideration $— $— $— ($85,625 ) Contingent Utica Consideration — 7,985 — — Contingent Marcellus Consideration — 2,205 — — Contingent Niobrara Consideration — — — — Contingent consideration $— $10,190 $— ($85,625 ) Consolidated Statements of Income Three Months Ended March 31, 2018 (Gain) Loss on Derivatives, Net (In thousands) Contingent ExL Consideration $5,830 Contingent Utica Consideration (1,020 ) Contingent Marcellus Consideration 470 Contingent Niobrara Consideration (385 ) Contingent consideration $4,895
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 March 31, 2018 and December 31, 2017 are summarized below: March 31, 2018 Gross Amounts Recognized Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts Presented in the Consolidated Balance Sheets (In thousands) Commodity derivative instruments $15,494 ($15,027 ) $467 Deferred premium obligations — — — Contingent consideration 9,460 — 9,460 Other current assets $24,954 ($15,027 ) $9,927 Commodity derivative instruments 9,855 (9,830 ) 25 Deferred premium obligations — — — Contingent consideration 9,545 — 9,545 Other assets-non current $19,400 ($9,830 ) $9,570 Commodity derivative instruments ($73,280 ) $15,027 ($58,253 ) Deferred premium obligations (9,746 ) — (9,746 ) Contingent consideration (47,260 ) — (47,260 ) Derivative liabilities-current ($130,286 ) $15,027 ($115,259 ) Commodity derivative instruments (27,019 ) 9,830 (17,189 ) Deferred premium obligations (9,468 ) — (9,468 ) Contingent consideration (44,195 ) — (44,195 ) Derivative liabilities-non current ($80,682 ) $9,830 ($70,852 ) 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 ) $— Deferred premium obligations — — — Other current assets $4,869 ($4,869 ) $— Commodity derivative instruments 9,505 (9,505 ) — Deferred premium obligations — — — Contingent consideration 10,190 — 10,190 Other assets-non current $19,695 ($9,505 ) $10,190 Commodity derivative instruments ($52,671 ) $4,869 ($47,802 ) Deferred premium obligations (9,319 ) — (9,319 ) Derivative liabilities-current ($61,990 ) $4,869 ($57,121 ) Commodity derivative instruments (24,609 ) 9,505 (15,104 ) Deferred premium obligations (11,603 ) — (11,603 ) Contingent consideration (85,625 ) — (85,625 ) Derivative liabilities-non current ($121,837 ) $9,505 ($112,332 )
Schedule of (Gain) Loss on Derivative Instruments	The effect of derivative instruments and deferred premium obligations in the consolidated statements of income for the three months ended March 31, 2018 and 2017 is summarized below: Three Months Ended 2018 2017 (In thousands) (Gain) Loss on Derivatives, Net Crude oil $29,511 ($18,480 ) Natural gas liquids (1,765 ) — Natural gas (3,045 ) (6,836 ) Contingent consideration 4,895 — Total (Gain) Loss on Derivatives, Net $29,596 ($25,316 )
Schedule Of Cash Received For Derivatives	The effect of commodity derivative instruments and deferred premium obligations in the consolidated statements of cash flows for the three months ended March 31, 2018 and 2017 is summarized below: Three Months Ended 2018 2017 (In thousands) Cash Received (Paid) for Derivative Settlements, Net Crude oil ($12,123 ) $3,031 Natural gas liquids (432 ) — Natural gas 52 (1,149 ) Deferred premium obligations paid (1,862 ) (363 ) Total Cash Received (Paid) for Derivative Settlements, Net ($14,365 ) $1,519
Crude Oil
Derivative [Line Items]
Schedule of Derivative Instruments	The following table sets forth a summary of the Company’s outstanding crude oil derivative positions at weighted average contract prices as of March 31, 2018 : Period Type of Contract Index Volumes (Bbls/d) Fixed Price ($/Bbl) Sub-Floor Price ($/Bbl) Floor Price ($/Bbl) Ceiling Price ($/Bbl) 2018 Q2 - Q4 2018 Fixed Price Swaps NYMEX WTI 6,000 $49.55 $— $— $— Q2 - Q4 2018 Basis Swaps (1) 6,000 2.91 — — — Q2 - Q4 2018 Basis Swaps (2) 6,000 (0.10 ) — — — Q2 - Q4 2018 Three-Way Collars NYMEX WTI 24,000 — 39.38 49.06 60.14 Q2 - Q4 2018 Net Sold Call Options NYMEX WTI 3,388 — — — 71.33 2019 Q1 - Q2 2019 Basis Swaps (2) 500 (2.99 ) — — — Q1 - Q4 2019 Three-Way Collars NYMEX WTI 12,000 — 40.00 48.40 60.29 Q1 - Q4 2019 Net Sold Call Options NYMEX WTI 3,875 — — — 73.66 2020 Q1 - Q4 2020 Net Sold Call Options NYMEX WTI 4,575 — — — 75.98 (1) The Company has entered into crude oil basis swaps in order to fix the differential between LLS-Cushing. The weighted average price differential represents the amount of premium to Cushing for the volumes presented in the table above. (2) The Company has entered into crude oil basis swaps in order to fix the differential between Midland-Cushing. The weighted average price differential represents the amount of reduction to Cushing for the volumes presented in the table above. In April 2018, the Company entered into the following crude oil derivative positions at the weighted average contract prices summarized below: Period Type of Contract Index Volumes (Bbls/d) Fixed Price ($/Bbl) Sub-Floor Price ($/Bbl) Floor Price ($/Bbl) Ceiling Price ($/Bbl) 2019 Q1 - Q2 2019 Basis Swaps (1) 2,500 ($4.00 ) $— $— $— Q3 - Q4 2019 Basis Swaps (1) 3,000 (4.00 ) — — — Q1 - Q4 2019 Three-Way Collars NYMEX WTI 3,000 — 45.00 55.00 71.21 (1) The Company has entered into crude oil basis swaps in order to fix the differential between Midland-Cushing. The weighted average price differential represents the amount of reduction to Cushing for the volumes presented in the table above.
Natural Gas Liquids
Derivative [Line Items]
Schedule of Derivative Instruments	The following table sets forth a summary of the Company’s outstanding NGL derivative positions at weighted average contract prices as of March 31, 2018 : Period Type of Contract Index Volumes (Bbls/d) Fixed Price ($/Bbl) 2018 Q2 - Q4 2018 Fixed Price Swaps Ethane - OPIS Mont Belvieu Non-TET 2,200 $12.01 Q2 - Q4 2018 Fixed Price Swaps Propane - OPIS Mont Belvieu Non-TET 1,500 34.23 Q2 - Q4 2018 Fixed Price Swaps Butane - OPIS Mont Belvieu Non-TET 200 38.85 Q2 - Q4 2018 Fixed Price Swaps Isobutane - OPIS Mont Belvieu Non-TET 600 38.98 Q2 - Q4 2018 Fixed Price Swaps Natural Gasoline - OPIS Mont Belvieu Non-TET 600 55.23
Natural Gas
Derivative [Line Items]
Schedule of Derivative Instruments	The following table sets forth a summary of the Company’s outstanding natural gas derivative positions at weighted average contract prices as of March 31, 2018 : Period Type of Contract Index Volumes (MMBtu/d) Fixed Price ($/Bbl) Ceiling Price ($/Bbl) 2018 Q2 - Q4 2018 Fixed Price Swaps NYMEX HH 25,000 $3.01 $— Q2 - Q4 2018 Sold Call Options NYMEX HH 33,000 — 3.25 2019 Q1 - Q4 2019 Sold Call Options NYMEX HH 33,000 — 3.25 2020 Q1 - Q4 2020 Sold Call Options NYMEX HH 33,000 — 3.50

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following tables summarize the Company’s assets and liabilities measured at fair value on a recurring basis as of March 31, 2018 and December 31, 2017 : March 31, 2018 Level 1 Level 2 Level 3 (In thousands) Derivative instrument assets $— $492 $19,005 Derivative instrument liabilities $— ($75,442 ) ($91,455 ) December 31, 2017 Level 1 Level 2 Level 3 (In thousands) Derivative instrument assets $— $— $10,190 Derivative instrument liabilities $— ($62,906 ) ($85,625 )
Fair Value, Assets Measured on Recurring Basis, Level 3 Reconciliation	Three Months Ended March 31, 2018 (In thousands) Fair value assets, beginning of period $10,190 Recognition of divestiture date fair value 7,880 Gain (loss) on changes in fair value (1) 935 Transfers into (out of) Level 3 — Fair value assets, end of period $19,005
Fair Value, Liabilities Measured on Recurring Basis, Level 3 Reconciliation	Three Months Ended March 31, 2018 (In thousands) Fair value liability, beginning of period ($85,625 ) Gain (loss) on changes in fair value (1) (5,830 ) Transfers into (out of) Level 3 — Fair value liability, end of period ($91,455 )
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, net of unamortized premiums and debt issuance costs, with the fair values measured using quoted secondary market trading prices. March 31, 2018 December 31, 2017 Carrying Amount Fair Value Carrying Amount Fair Value (In thousands) 7.50% Senior Notes due 2020 $128,947 $132,236 $446,087 $459,518 6.25% Senior Notes due 2023 642,116 650,540 641,792 674,375 8.25% Senior Notes due 2025 245,710 262,500 245,605 274,375 Other long-term debt due 2028 4,425 4,348 4,425 4,445

Condensed Consolidating Finan30

Condensed Consolidating Financial Information (Tables)	3 Months Ended
	Mar. 31, 2018
Condensed Consolidating Financial Information [Abstract]
Schedule Of Condensed Consolidating Balance Sheets	CARRIZO OIL & GAS, INC. CONDENSED CONSOLIDATING BALANCE SHEETS (In thousands) (Unaudited) March 31, 2018 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Assets Total current assets $3,121,696 $105,225 $— ($3,107,720 ) $119,201 Total property and equipment, net 6,075 2,395,752 3,028 (3,870 ) 2,400,985 Investment in subsidiaries (884,965 ) — — 884,965 — Other assets 8,725 9,546 — — 18,271 Total Assets $2,251,531 $2,510,523 $3,028 ($2,226,625 ) $2,538,457 Liabilities and Shareholders’ Equity Current liabilities $209,448 $3,329,846 $3,028 ($3,110,741 ) $431,581 Long-term liabilities 1,461,955 65,642 — 15,880 1,543,477 Preferred stock 172,118 — — — 172,118 Total shareholders’ equity 408,010 (884,965 ) — 868,236 391,281 Total Liabilities and Shareholders’ Equity $2,251,531 $2,510,523 $3,028 ($2,226,625 ) $2,538,457 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 OPERATIONS (In thousands) (Unaudited) Three Months Ended March 31, 2018 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Total revenues $20 $225,260 $— $— $225,280 Total costs and expenses 87,365 110,113 — (9 ) 197,469 Income (loss) before income taxes (87,345 ) 115,147 — 9 27,811 Income tax benefit — (319 ) — — (319 ) Equity in income of subsidiaries 114,828 — — (114,828 ) — Net income $27,483 $114,828 $— ($114,819 ) $27,492 Dividends on preferred stock (4,863 ) — — — (4,863 ) Accretion on preferred stock (753 ) — — — (753 ) Loss on redemption of preferred stock (7,133 ) — — — (7,133 ) Net income attributable to common shareholders $14,734 $114,828 $— ($114,819 ) $14,743 Three Months Ended March 31, 2017 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Total revenues $82 $151,273 $— $— $151,355 Total costs and expenses 18,868 92,456 — 10 111,334 Loss before income taxes (18,786 ) 58,817 — (10 ) 40,021 Income tax benefit — — — — — Equity in loss of subsidiaries 58,817 — — (58,817 ) — Net loss $40,031 $58,817 $— ($58,827 ) $40,021 Dividends on preferred stock — — — — — Accretion on preferred stock — — — — — Loss on redemption of preferred stock — — — — — Net income attributable to common shareholders $40,031 $58,817 $— ($58,827 ) $40,021 CARRIZO OIL & GAS, INC. CONDENSED CONSOLIDATING STATEMENTS OF INCOME (In thousands) (Unaudited) Three Months Ended March 31, 2018 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Total revenues $20 $225,260 $— $— $225,280 Total costs and expenses 87,365 110,113 — (9 ) 197,469 Income (loss) before income taxes (87,345 ) 115,147 — 9 27,811 Income tax expense — (319 ) — — (319 ) Equity in income of subsidiaries 114,828 — — (114,828 ) — Net income $27,483 $114,828 $— ($114,819 ) $27,492 Dividends on preferred stock (4,863 ) — — — (4,863 ) Accretion on preferred stock (753 ) — — — (753 ) Loss on redemption of preferred stock (7,133 ) — — — (7,133 ) Net income attributable to common shareholders $14,734 $114,828 $— ($114,819 ) $14,743 Three Months Ended March 31, 2017 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Total revenues $82 $151,273 $— $— $151,355 Total costs and expenses 18,868 92,456 — 10 111,334 Income (loss) before income taxes (18,786 ) 58,817 — (10 ) 40,021 Income tax expense — — — — — Equity in income of subsidiaries 58,817 — — (58,817 ) — Net income $40,031 $58,817 $— ($58,827 ) $40,021 Dividends on preferred stock — — — — — Accretion on preferred stock — — — — — Loss on redemption of preferred stock — — — — — Net income attributable to common shareholders $40,031 $58,817 $— ($58,827 ) $40,021
Schedule Of Condensed Consolidating Statements Of Cash Flows	CARRIZO OIL & GAS, INC. CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS (In thousands) (Unaudited) Three Months Ended March 31, 2018 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Net cash provided by (used in) operating activities ($88,377 ) $227,101 $— $— $138,724 Net cash provided by investing activities 334,688 107,862 — (334,963 ) 107,587 Net cash used in financing activities (250,966 ) (334,963 ) — 334,963 (250,966 ) Net decrease in cash and cash equivalents (4,655 ) — — — (4,655 ) Cash and cash equivalents, beginning of period 9,540 — — — 9,540 Cash and cash equivalents, end of period $4,885 $— $— $— $4,885 Three Months Ended March 31, 2017 Parent Company Combined Guarantor Subsidiaries Combined Non- Guarantor Subsidiaries Eliminations Consolidated Net cash provided by (used in) operating activities ($47,297 ) $123,705 $— $— $76,408 Net cash provided by (used in) investing activities 9,879 (114,212 ) — (9,493 ) (113,826 ) Net cash provided by (used in) financing activities 35,615 (9,493 ) — 9,493 35,615 Net decrease in cash and cash equivalents (1,803 ) — — — (1,803 ) Cash and cash equivalents, beginning of period 4,194 — — — 4,194 Cash and cash equivalents, end of period $2,391 $— $— $— $2,391

Supplemental Cash Flow Inform31

Supplemental Cash Flow Information (Tables)	3 Months Ended
	Mar. 31, 2018
Supplemental Cash Flow Elements [Abstract]
Schedule of Cash Flow, Supplemental Disclosures	Supplemental cash flow disclosures and non-cash investing activities are presented below: Three Months Ended 2018 2017 (In thousands) Supplemental cash flow disclosures: Cash paid for interest, net of amounts capitalized $14,855 $19,480 Non-cash investing activities: Increase (decrease) in capital expenditure payables and accruals ($9,677 ) $28,139 Contingent consideration related to divestitures of oil and gas properties (7,880 ) —

Subsequent Events (Tables)

Subsequent Events (Tables)	3 Months Ended
	Mar. 31, 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 at weighted average contract prices as of March 31, 2018 : Period Type of Contract Index Volumes (Bbls/d) Fixed Price ($/Bbl) Sub-Floor Price ($/Bbl) Floor Price ($/Bbl) Ceiling Price ($/Bbl) 2018 Q2 - Q4 2018 Fixed Price Swaps NYMEX WTI 6,000 $49.55 $— $— $— Q2 - Q4 2018 Basis Swaps (1) 6,000 2.91 — — — Q2 - Q4 2018 Basis Swaps (2) 6,000 (0.10 ) — — — Q2 - Q4 2018 Three-Way Collars NYMEX WTI 24,000 — 39.38 49.06 60.14 Q2 - Q4 2018 Net Sold Call Options NYMEX WTI 3,388 — — — 71.33 2019 Q1 - Q2 2019 Basis Swaps (2) 500 (2.99 ) — — — Q1 - Q4 2019 Three-Way Collars NYMEX WTI 12,000 — 40.00 48.40 60.29 Q1 - Q4 2019 Net Sold Call Options NYMEX WTI 3,875 — — — 73.66 2020 Q1 - Q4 2020 Net Sold Call Options NYMEX WTI 4,575 — — — 75.98 (1) The Company has entered into crude oil basis swaps in order to fix the differential between LLS-Cushing. The weighted average price differential represents the amount of premium to Cushing for the volumes presented in the table above. (2) The Company has entered into crude oil basis swaps in order to fix the differential between Midland-Cushing. The weighted average price differential represents the amount of reduction to Cushing for the volumes presented in the table above. In April 2018, the Company entered into the following crude oil derivative positions at the weighted average contract prices summarized below: Period Type of Contract Index Volumes (Bbls/d) Fixed Price ($/Bbl) Sub-Floor Price ($/Bbl) Floor Price ($/Bbl) Ceiling Price ($/Bbl) 2019 Q1 - Q2 2019 Basis Swaps (1) 2,500 ($4.00 ) $— $— $— Q3 - Q4 2019 Basis Swaps (1) 3,000 (4.00 ) — — — Q1 - Q4 2019 Three-Way Collars NYMEX WTI 3,000 — 45.00 55.00 71.21 (1) The Company has entered into crude oil basis swaps in order to fix the differential between Midland-Cushing. The weighted average price differential represents the amount of reduction to Cushing for the volumes presented in the table above.

Summary of Significant Accoun33

Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Summary Of Significant Accounting Policies [Line Items]
Accrued Fees and Other Revenue Receivable	$ 66.3	$ 85.6

Summary of Significant Accoun34

Summary of Significant Accounting Policies (Schedule of Impact of Adoption) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Crude oil revenues	$ 194,919	$ 128,092
Natural gas liquids revenues	16,902	7,425
Natural gas revenues	13,459	15,838
Oil and Gas Sales Revenue	225,280	151,355
Lease operating	39,273	29,845
Income before income taxes	27,811	$ 40,021
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Crude oil revenues	194,794
Natural gas liquids revenues	16,096
Natural gas revenues	12,887
Oil and Gas Sales Revenue	223,777
Lease operating	37,770
Income before income taxes	27,811
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Crude oil revenues	125
Natural gas liquids revenues	806
Natural gas revenues	572
Oil and Gas Sales Revenue	1,503
Lease operating	1,503
Income before income taxes	$ 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%
Natural Gas Liquids
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Percent Difference Between Revenue Guidance In Effect Before And After Topic 606	5.00%
Natural Gas
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Percent Difference Between Revenue Guidance In Effect Before And After Topic 606	4.40%
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%
Lease Operating Expense
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Percent Difference Between Revenue Guidance In Effect Before And After Topic 606	4.00%
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%

Summary of Significant Accoun35

Summary of Significant Accounting Policies (Schedule of Earnings Per Share Reconciliation) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net Income Attributable to Common Shareholders	$ 14,743	$ 40,021
Basic weighted average common shares outstanding	81,542	65,188
Effect of dilutive instruments	1,036	590
Diluted weighted average common shares outstanding	82,578	65,778
Net Income (Loss) - basic (in dollars per share)	$ 0.18	$ 0.61
Net Income (Loss) - diluted (in dollars per share)	$ 0.18	$ 0.61

Summary of Significant Accoun36

Summary of Significant Accounting Policies (Schedule of Antidilutive Shares Excluded from Earnings Per Share) (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Effect of dilutive instruments	1,036	590
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	98	5

Acquisitions and Divestitures (

Acquisitions and Divestitures (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Dec. 31, 2017	Jan. 19, 2018
Business Acquisition [Line Items]
Payments to Acquire Oil and Gas Property	$ 0	$ 7,032
Proceeds from divestitures of oil and gas properties, net	342,359	$ 17,372
Senior Secured Revolving Credit Facility [Member]
Business Acquisition [Line Items]
Long-term Line of Credit	421,700		$ 421,700	$ 291,300
ExL Acquisition
Business Acquisition [Line Items]
Payments to Acquire Oil and Gas Property				679,800
Contingent Consideration, Range of Outcomes, Value, High	125,000		125,000
Business Combination, Contingent Consideration, Liability	91,455		91,455	85,600
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual	43,500
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual	34,800
ExL Acquisition | Maximum [Member]
Business Acquisition [Line Items]
Potential Additional Annual Payments for Acquisition	50,000
Niobrara Divestiture
Business Acquisition [Line Items]
Business Combination, Contingent Consideration, Asset	8,300		8,300		$ 7,900
Proceeds from divestitures of oil and gas properties, net			132,300
Niobrara Divestiture | Maximum [Member]
Business Acquisition [Line Items]
Potential Additional Annual Proceeds From Divestiture	5,000
Eagle Ford Shale Divestiture
Business Acquisition [Line Items]
Proceeds from divestitures of oil and gas properties, net			247,100
Utica Shale Divestiture
Business Acquisition [Line Items]
Business Combination, Contingent Consideration, Asset	9,000		9,000	8,000
Proceeds from divestitures of oil and gas properties, net				63,100
Utica Shale Divestiture | Maximum [Member]
Business Acquisition [Line Items]
Potential Additional Annual Proceeds From Divestiture	5,000
Marcellus Shale Divestiture
Business Acquisition [Line Items]
Contingent Consideration, Range of Outcomes, Value, High	7,500		7,500
Business Combination, Contingent Consideration, Asset	1,700		$ 1,700	2,200
Proceeds from divestitures of oil and gas properties, net				$ 73,900
Marcellus Shale Divestiture | Maximum [Member]
Business Acquisition [Line Items]
Potential Additional Annual Proceeds From Divestiture	$ 3,000

Property and Equipment, Net (Na

Property and Equipment, Net (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)$ / Boe	Mar. 31, 2017USD ($)$ / Boe
Property, Plant and Equipment [Line Items]
Average depreciation, depletion and amortization, per Boe | $ / Boe	13.73	12.69
Internal costs capitalized, Oil and Gas producing activities	$ 6.6	$ 5.4
Capitalized interest	$ 10.4	$ 3.8

Property And Equipment, Net (Sc

Property And Equipment, Net (Schedule Of Property And Equipment) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Proved properties	$ 5,486,064	$ 5,615,153
Accumulated depreciation, depletion and amortization and impairments	(3,713,137)	(3,649,806)
Proved properties, net	1,772,927	1,965,347
Unproved properties, not being amortized
Unevaluated leasehold and seismic costs	564,984	612,589
Capitalized interest	52,770	47,698
Total unproved properties, not being amortized	617,754	660,287
Other property and equipment	26,332	25,625
Accumulated depreciation	(16,028)	(15,449)
Other property and equipment, net	10,304	10,176
Total property and equipment, net	$ 2,400,985	$ 2,635,810

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Income Taxes [Line Items]
U.S. federal statutory corporate pretax rate	21.00%	35.00%
State and Local Income Taxes	$ 319,000		$ 710,000
Tax Adjustments, Settlements, and Unusual Provisions			15,700,000
Tax Adjustments Retained Earnings Effect			0
Deferred Tax Assets, Valuation Allowance	(324,625,000)
Change in Deferred Tax Assets Valuation Allowance	$ (8,401,000)		$ (17,369,000)

Income Taxes (Schedule Of Effec

Income Taxes (Schedule Of Effective Income Tax Rate Reconciliation) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Income before income taxes	$ 27,811	$ 40,021
Income tax expense at the statutory rate	(5,840)	(14,007)
State income tax expense, net of U.S. federal income taxes	(319)	(710)
Tax shortfalls from stock-based compensation expense	(2,526)	(2,592)
Decrease in deferred tax assets valuation allowance	8,401	17,369
Other	(35)	(60)
Income tax expense	$ (319)	$ 0

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details)	1 Months Ended		3 Months Ended
	Mar. 31, 2018USD ($)	Feb. 28, 2018USD ($)	Mar. 31, 2018USD ($)Rate	Mar. 31, 2017USD ($)	Mar. 02, 2018USD ($)	Feb. 20, 2018USD ($)	Dec. 31, 2017USD ($)
Debt Instrument [Line Items]
Loss on extinguishment of debt			$ 8,676,000	$ 0
Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity	$ 830,000,000		830,000,000				$ 900,000,000
Line of Credit Facility, Elected Borrowing Capacity	800,000,000		800,000,000
Line of credit facility amount outstanding	$ 421,700,000		$ 421,700,000				291,300,000
Debt, Weighted Average Interest Rate	4.24%		4.24%
Letters of credit outstanding amount	$ 0		$ 0
Ratio of total debt to EBITDA			2.60
Current Ratio	1.52		1.52
Pre-Tax SEC PV10 Reserve Value Percentage | Rate			90.00%
Federal funds rate plus percentage	0.50%		0.50%
Adjusted LIBO rate plus percentage	1.00%		1.00%
Senior Secured Revolving Credit Facility [Member] | Maximum [Member]
Debt Instrument [Line Items]
Ratio of total debt to EBITDA			4
Senior Secured Revolving Credit Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
Current Ratio	1		1
7.50% Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.50%		7.50%
Long term debt	$ 130,000,000		$ 130,000,000				450,000,000
8.25% Senior Notes [Member]
Debt Instrument [Line Items]
Long term debt	250,000,000		$ 250,000,000				$ 250,000,000
February 2018 7.50% Senior Note Redemption [Member]
Debt Instrument [Line Items]
Debt Instrument, Repurchased Face Amount						$ 100,000,000
Cash paid for debt redemption		$ 105,100,000
Redemption Premium		1,900,000
Accrued interest paid associated with redemption of debt		3,200,000
Loss on extinguishment of debt		2,700,000
Write off of Deferred Debt Issuance Cost		$ 800,000
March 2018 7.50% Senior Note Redemption [Member]
Debt Instrument [Line Items]
Debt Instrument, Repurchased Face Amount					$ 220,000,000
Cash paid for debt redemption	231,800,000
Redemption Premium	4,100,000
Accrued interest paid associated with redemption of debt	7,700,000
Loss on extinguishment of debt	6,000,000
Write off of Deferred Debt Issuance Cost	$ 1,900,000

Long-Term Debt (Schedule of Lon

Long-Term Debt (Schedule of Long-Term Debt) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long-term debt	$ 1,442,898	$ 1,629,209
Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility amount outstanding	421,700	291,300
7.50% Senior Notes [Member]
Debt Instrument [Line Items]
Long term debt	130,000	450,000
Debt instrument, unamortized premium	153	579
Unamortized Debt Issuance Expense	(1,206)	(4,492)
6.25% Senior Notes [Member]
Debt Instrument [Line Items]
Long term debt	650,000	650,000
Unamortized Debt Issuance Expense	(7,884)	(8,208)
8.25% Senior Notes [Member]
Debt Instrument [Line Items]
Long term debt	250,000	250,000
Unamortized Debt Issuance Expense	(4,290)	(4,395)
Other Long Term Debt [Member]
Debt Instrument [Line Items]
Long term debt	$ 4,425	$ 4,425

Long-Term Debt (Interest and Co

Long-Term Debt (Interest and Commitment Fee Rates) (Details)	3 Months Ended
	Mar. 31, 2018
Less than 25 percent [Member]
Interest and Commitment Fee Rates [Line Items]
Margin for base rate loans	1.00%
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	1.25%
Margin for eurodollar loans	2.25%
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	1.50%
Margin for eurodollar loans	2.50%
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	1.75%
Margin for eurodollar loans	2.75%
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	2.00%
Line of Credit Facility, Commitment Fee Percentage	0.50%

Preferred Stock (Narrative) (De

Preferred Stock (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended
	Mar. 31, 2018	Jan. 31, 2018	Mar. 31, 2018	Sep. 30, 2017	Mar. 31, 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			(7,133)		$ 0
Total Consideration for Repurchase of Preferred Stock			$ 50,030
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	$ (4,400)	$ (500)	$ (4,863)		0
Accretion on preferred stock			$ (753)		$ 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)	Mar. 31, 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)	3 Months Ended
	Mar. 31, 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 48

Preferred Stock (Schedule of Preferred Stock Activity) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 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 March 31, 2018 and 250,000 issued and outstanding as of December 31, 2017	$ 172,118,000		$ 214,262,000
Redemption of Preferred Stock	(42,897,000)
Accretion on preferred stock	$ (753,000)	$ 0

Shareholders' Equity and Stoc49

Shareholders' Equity and Stock Incentive Plans (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized (in shares)	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]
Granted Shares/Units	1,347,165
Nonvested Awards, Compensation Cost Not yet Recognized	$ 35
Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	2 years 4 months 24 days
Equity Instruments Other than Options, Vested in Period	564,912
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
Fair Value of Shares Issued	$ 19.7
Vesting period, in years	3 years
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
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	$ 2.9
Nonvested Awards, Compensation Cost Not yet Recognized	$ 5.8
Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	2 years 9 months 18 days
SARs, Granted	616,686
Stock Appreciation Rights (SARs) [Member] | Other Current Liabilities [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Liability For Cash Stock Appreciation Rights	$ 0.1
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	$ 2.8	$ 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	$ 3.3
Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	2 years 4 months 24 days
Performance shares vested per TSR ranking	56,517
Equity Instruments Other than Options, Vested in Period	49,458
Vesting percentage of target performance shares granted	88.00%
Performance Shares [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award Vesting Rights Percentage Range	200.00%
Performance Shares [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award Vesting Rights Percentage Range	0.00%
2017 Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Available for Grant	318,109
Ratio of stock based compensation shares to common shares	1.35

Shareholders' Equity and Stoc50

Shareholders' Equity and Stock Incentive Plans (Summary of Restricted Stock Award and Unit Activity) (Details) - Restricted Stock Awards And Units [Member]	3 Months Ended
	Mar. 31, 2018$ / sharesshares
Restricted Stock Awards and Units [Abstract]
Unvested Shares/Units, Beginning of Period | shares	1,482,655
Granted Shares/Units | shares	1,347,165
Vested Shares/Units | shares	(564,912)
Forfeited Shares/Units | shares	(1,078)
Unvested Shares/Units, End of Period | shares	2,263,830
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	31.87
Forfeited, Grant Date Fair Value (USD per share) | $ / shares	29.61
Grant Date Fair Value, End of Period (USD per share) | $ / shares	$ 19.15

Shareholders' Equity and Stoc51

Shareholders' Equity and Stock Incentive Plans (Summary of SARs Activity) (Details) - Stock Appreciation Rights (SARs) [Member] $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 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	0
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	5 years 1 month 7 days
Weighted Average Remaining Life, Exercisable, End of Period	3 years 3 months 18 days
Aggregate Intrinsic Value, Outstanding, End of Period | $	$ 0.7
Aggregate Intrinsic Value, Exercisable, End of Period | $	$ 0

Shareholders' Equity and Stoc52

Shareholders' Equity and Stock Incentive Plans (Summary of SARs Fair Value Assumptions) (Details) - Stock Appreciation Rights (SARs) [Member]	3 Months Ended
	Mar. 31, 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 Stoc53

Shareholders' Equity and Stock Incentive Plans (Summary of Performance Share Award Activity) (Details) - Performance Shares [Member]	3 Months Ended
	Mar. 31, 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	(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	65.51
Grant Date Fair Value, End of Period (USD per share) | $ / shares	$ 27.01

Shareholders' Equity and Stoc54

Shareholders' Equity and Stock Incentive Plans (Summary of Performance Share Awards Fair Value Assumptions) (Details) - Performance Shares [Member]	3 Months Ended
	Mar. 31, 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 Stoc55

Shareholders' Equity and Stock Incentive Plans (Schedule of Share-Based Compensation Expense) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated Share-based Compensation Expense	$ 4,226	$ 2,869
Less: amounts capitalized	(708)	(855)
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost	3,518	2,014
Restricted Stock Awards And Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated Share-based Compensation Expense	5,084	5,849
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated Share-based Compensation Expense	(1,415)	(3,686)
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated Share-based Compensation Expense	$ 557	$ 706

Derivative Instruments (Narrati

Derivative Instruments (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)$ / bbls$ / MMBTU	Jan. 19, 2018USD ($)	Dec. 31, 2017USD ($)
ExL Acquisition
Derivative [Line Items]
Contingent Consideration, Range of Outcomes, Value, High	$ 125,000
Threshold Price per Bbl for Additional Payments for Acquisition | $ / bbls	50
Business Combination, Contingent Consideration, Liability	$ 91,455		$ 85,600
ExL Acquisition | Maximum [Member]
Derivative [Line Items]
Potential Additional Annual Payments for Acquisition	50,000
Utica Shale Divestiture
Derivative [Line Items]
Business Combination, Contingent Consideration, Asset	9,000		8,000
Utica Shale Divestiture | Maximum [Member]
Derivative [Line Items]
Potential Additional Annual Proceeds From Divestiture	$ 5,000
Utica Shale Divestiture | FY 2018 [Member]
Derivative [Line Items]
Threshold Price Per Bbl For Additional Proceeds From Divestiture | $ / bbls	50
Utica Shale Divestiture | FY 2019 [Member]
Derivative [Line Items]
Threshold Price Per Bbl For Additional Proceeds From Divestiture | $ / bbls	53
Utica Shale Divestiture | FY 2020 [Member]
Derivative [Line Items]
Threshold Price Per Bbl For Additional Proceeds From Divestiture | $ / bbls	56
Marcellus Shale Divestiture
Derivative [Line Items]
Contingent Consideration, Range of Outcomes, Value, High	$ 7,500
Business Combination, Contingent Consideration, Asset	1,700		$ 2,200
Marcellus Shale Divestiture | Maximum [Member]
Derivative [Line Items]
Potential Additional Annual Proceeds From Divestiture	$ 3,000
Marcellus Shale Divestiture | FY 2018 [Member]
Derivative [Line Items]
Threshold Price per MMBtu for Additional Payments from Divestiture | $ / MMBTU	3.13
Marcellus Shale Divestiture | FY 2019 [Member]
Derivative [Line Items]
Threshold Price per MMBtu for Additional Payments from Divestiture | $ / MMBTU	3.18
Marcellus Shale Divestiture | FY 2020 [Member]
Derivative [Line Items]
Threshold Price per MMBtu for Additional Payments from Divestiture | $ / MMBTU	3.30
Niobrara Divestiture
Derivative [Line Items]
Business Combination, Contingent Consideration, Asset	$ 8,300	$ 7,900
Niobrara Divestiture | Maximum [Member]
Derivative [Line Items]
Potential Additional Annual Proceeds From Divestiture	$ 5,000
Niobrara Divestiture | FY 2018 and FY 2019 [Member]
Derivative [Line Items]
Threshold Price Per Bbl For Additional Proceeds From Divestiture | $ / bbls	55
Niobrara Divestiture | FY 2020 [Member]
Derivative [Line Items]
Threshold Price Per Bbl For Additional Proceeds From Divestiture | $ / bbls	60

Derivative Instruments (Schedul

Derivative Instruments (Schedule of Crude Oil Derivative Positions) (Details) - Crude Oil	Mar. 31, 2018bbl / d$ / bbls
Q2 - Q4 2018 | Fixed Price Swaps
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	6,000
Weighted Average Fixed Price ($/Bbl)	49.55
Q2 - Q4 2018 | Basis Swaps | LLS-NYMEX Price Differential
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	6,000
Weighted Average Fixed Price ($/Bbl)	2.91
Q2 - Q4 2018 | Basis Swaps | Midland-NYMEX Price Differential
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	6,000
Weighted Average Fixed Price ($/Bbl)	0.10
Q2 - Q4 2018 | Three-way Collars
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	24,000
Weighted Average Sub-Floor Price ($/Bbls)	39.38
Weighted Average Floor Price ($/Bbls)	49.06
Weighted Average Ceiling Price ($/Bbls)	60.14
Q2 - Q4 2018 | Call Option
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	3,388
Weighted Average Ceiling Price ($/Bbls)	71.33
1H 2019 | Basis Swaps | Midland-NYMEX Price Differential
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	500
Weighted Average Fixed Price ($/Bbl)	2.99
FY 2019 | Three-way Collars
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	12,000
Weighted Average Sub-Floor Price ($/Bbls)	40
Weighted Average Floor Price ($/Bbls)	48.40
Weighted Average Ceiling Price ($/Bbls)	60.29
FY 2019 | Call Option
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	3,875
Weighted Average Ceiling Price ($/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 (Sched58

Derivative Instruments (Schedule of NGL Derivative Positions) (Details) - Q2 - Q4 2018 - Natural Gas Liquids - Fixed Price Swaps	Mar. 31, 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 (Sched59

Derivative Instruments (Schedule of Natural Gas Derivative Positions) (Details) - Natural Gas	Mar. 31, 2018MMBTU / d$ / MMBTU
Q2 - Q4 2018 | Fixed Price Swaps
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBTU / d	25,000
Weighted Average Fixed Price ($/MMBtu) | $ / MMBTU	3.01
Q2 - 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 (Sched60

Derivative Instruments (Schedule of Contingent Consideration) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Embedded Derivative [Line Items]
Contingent Consideration, Current Asset	$ 9,460		$ 0
Contingent Consideration, Noncurrent Asset	9,545		10,190
Contingent Consideration, Current Liability	(47,260)		0
Contingent Consideration, Noncurrent Liability	44,195		85,625
Gain (Loss) on Embedded Derivative, Net	4,895	$ 0
ExL Acquisition
Embedded Derivative [Line Items]
Contingent Consideration, Current Asset	0		0
Contingent Consideration, Noncurrent Asset	0		0
Contingent Consideration, Current Liability	(47,260)		0
Contingent Consideration, Noncurrent Liability	44,195		85,625
Gain (Loss) on Embedded Derivative, Net	5,830
Utica Shale Divestiture
Embedded Derivative [Line Items]
Contingent Consideration, Current Asset	4,685		0
Contingent Consideration, Noncurrent Asset	4,320		7,985
Contingent Consideration, Current Liability	0		0
Contingent Consideration, Noncurrent Liability	0		0
Gain (Loss) on Embedded Derivative, Net	(1,020)
Marcellus Shale Divestiture
Embedded Derivative [Line Items]
Contingent Consideration, Current Asset	360		0
Contingent Consideration, Noncurrent Asset	1,375		2,205
Contingent Consideration, Current Liability	0		0
Contingent Consideration, Noncurrent Liability	0		0
Gain (Loss) on Embedded Derivative, Net	470
Niobrara Divestiture
Embedded Derivative [Line Items]
Contingent Consideration, Current Asset	4,415		0
Contingent Consideration, Noncurrent Asset	3,850		0
Contingent Consideration, Current Liability	0		0
Contingent Consideration, Noncurrent Liability	0		$ 0
Gain (Loss) on Embedded Derivative, Net	$ (385)

Derivative Instruments (Sched61

Derivative Instruments (Schedule of Derivative Instruments in Statement of Financial Position) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Contingent Consideration, Current Asset	$ 9,460	$ 0
Contingent Consideration, Noncurrent Asset	9,545	10,190
Derivative liabilities, current	(115,259)	(57,121)
Derivative liabilities, noncurrent	(70,852)	(112,332)
Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	15,494	4,869
Derivative Asset, Deferred Premiums, Gross Asset	0	0
Contingent Consideration, Current Asset	9,460
Derivative Asset, Gross Asset	24,954	4,869
Derivative Asset, Fair Value, Gross Liability	(15,027)	(4,869)
Derivative Asset, Deferred Premiums, Gross Liability	0	0
Derivative Asset, Gross Liability	(15,027)	(4,869)
Derivative, Fair Value, Net	467	0
Derivative Deferred Premium, Net	0	0
Derivative assets, current	9,927	0
Other Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	9,855	9,505
Derivative Asset, Deferred Premiums, Gross Asset	0	0
Contingent Consideration, Noncurrent Asset	9,545	10,190
Derivative Asset, Gross Asset	19,400	19,695
Derivative Asset, Fair Value, Gross Liability	(9,830)	(9,505)
Derivative Asset, Deferred Premiums, Gross Liability	0	0
Derivative Asset, Gross Liability	(9,830)	(9,505)
Derivative, Fair Value, Net	25	0
Derivative Deferred Premium, Net	0	0
Derivative assets, noncurrent	9,570	10,190
Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net	(58,253)	(47,802)
Derivative Deferred Premium, Net	(9,746)	(9,319)
Derivative Liability, Fair Value, Gross Liability	(73,280)	(52,671)
Derivative Liability, Deferred Premiums, Gross Liability	(9,746)	(9,319)
Derivative Liability, Contingent Payment, Gross Liability	(47,260)
Derivative Liability, Gross Liability	(130,286)	(61,990)
Derivative Liability, Fair Value, Gross Asset	15,027	4,869
Derivative Liability, Deferred Premiums, Gross Asset	0	0
Derivative Liability, Gross Asset	15,027	4,869
Business Combination, Contingent Consideration, Liability	(47,260)
Derivative liabilities, current	(115,259)	(57,121)
Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net	(17,189)	(15,104)
Derivative Deferred Premium, Net	(9,468)	(11,603)
Derivative Liability, Fair Value, Gross Liability	(27,019)	(24,609)
Derivative Liability, Deferred Premiums, Gross Liability	(9,468)	(11,603)
Derivative Liability, Contingent Payment, Gross Liability	(44,195)	(85,625)
Derivative Liability, Gross Liability	(80,682)	(121,837)
Derivative Liability, Fair Value, Gross Asset	9,830	9,505
Derivative Liability, Deferred Premiums, Gross Asset	0	0
Derivative Liability, Gross Asset	9,830	9,505
Business Combination, Contingent Consideration, Liability	(44,195)	(85,625)
Derivative liabilities, noncurrent	$ (70,852)	$ (112,332)

Derivative Instruments (Sched62

Derivative Instruments (Schedule of (Gain) Loss on Derivative Instruments) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Derivative Instruments, Gain (Loss), Commodity [Line Items]
(Gain) loss on derivatives, net	$ 29,596	$ (25,316)
Gain (Loss) on Embedded Derivative, Net	4,895	0
Crude Oil
Derivative Instruments, Gain (Loss), Commodity [Line Items]
(Gain) loss on derivatives, net	29,511	(18,480)
Natural Gas Liquids
Derivative Instruments, Gain (Loss), Commodity [Line Items]
(Gain) loss on derivatives, net	(1,765)	0
Natural Gas
Derivative Instruments, Gain (Loss), Commodity [Line Items]
(Gain) loss on derivatives, net	$ (3,045)	$ (6,836)

Derivative Instruments (Sched63

Derivative Instruments (Schedule of Cash Received for Derivative Settlements) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Schedule Of Cash Received For Derivatives [Line Items]
Cash (paid) received for derivative settlements, net	$ (14,365)	$ 1,519
Crude Oil
Schedule Of Cash Received For Derivatives [Line Items]
Cash (paid) received for derivative settlements, net	(12,123)	3,031
Natural Gas Liquids
Schedule Of Cash Received For Derivatives [Line Items]
Cash (paid) received for derivative settlements, net	(432)	0
Natural Gas
Schedule Of Cash Received For Derivatives [Line Items]
Cash (paid) received for derivative settlements, net	52	(1,149)
Deferred Premiums on Derivative Instruments
Schedule Of Cash Received For Derivatives [Line Items]
Cash (paid) received for derivative settlements, net	$ (1,862)	$ (363)

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($)	Mar. 31, 2018	Mar. 31, 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	Mar. 31, 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	492	0
Derivative Liability	(75,442)	(62,906)
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	19,005	10,190
Derivative Liability	$ (91,455)	$ (85,625)

Fair Value Measurements (Sche66

Fair Value Measurements (Schedule of Assets, Level 3 Reconciliation) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$ 19,005	$ 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	935
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	$ 0

Fair Value Measurements (Sche67

Fair Value Measurements (Schedule of Liabilities, Level 3 Reconciliation) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	$ (91,455)	$ (85,625)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	(5,830)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3	$ 0

Fair Value Measurements (Sche68

Fair Value Measurements (Schedule of Carrying Value and Fair Value of Debt Instruments) (Details) - USD ($) $ in Thousands	Mar. 31, 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	128,947	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	132,236	459,518
6.25% Senior Notes [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	642,116	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	650,540	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	245,710	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	262,500	274,375
Other Long Term Debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	4,425	4,425
Other Long Term Debt [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	4,425	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	$ 4,348	$ 4,445

Condensed Consolidating Finan69

Condensed Consolidating Financial Information (Narrative) (Details)	Mar. 31, 2018
Condensed Consolidating Financial Information [Abstract]
Voting interest of the subsidiary owned by the registrant	100.00%

Condensed Consolidating Finan70

Condensed Consolidating Financial Information (Schedule Of Condensed Consolidating Balance Sheet) (Details) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Condensed Balance Sheet Statements, Captions [Line Items]
Total current assets	$ 119,201,000	$ 122,878,000
Total property and equipment, net	2,400,985,000	2,635,810,000
Investment in subsidiaries	0	0
Other assets	18,271,000	19,616,000
Total Assets	2,538,457,000	2,778,304,000
Current liabilities	431,581,000	372,822,000
Long-term liabilities	1,543,477,000	1,820,323,000
Preferred Stock	172,118,000	214,262,000
Total shareholders’ equity	391,281,000	370,897,000
Total Liabilities and Shareholders’ Equity	2,538,457,000	2,778,304,000
Eliminations [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Total current assets	(3,107,720,000)	(3,424,288,000)
Total property and equipment, net	(3,870,000)	(3,878,000)
Investment in subsidiaries	884,965,000	999,793,000
Other assets	0	0
Total Assets	(2,226,625,000)	(2,428,373,000)
Current liabilities	(3,110,741,000)	(3,427,308,000)
Long-term liabilities	15,880,000	15,879,000
Preferred Stock	0	0
Total shareholders’ equity	868,236,000	983,056,000
Total Liabilities and Shareholders’ Equity	(2,226,625,000)	(2,428,373,000)
Parent Company [Member] | Reportable Legal Entities [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Total current assets	3,121,696,000	3,441,633,000
Total property and equipment, net	6,075,000	5,953,000
Investment in subsidiaries	(884,965,000)	(999,793,000)
Other assets	8,725,000	9,270,000
Total Assets	2,251,531,000	2,457,063,000
Current liabilities	209,448,000	165,701,000
Long-term liabilities	1,461,955,000	1,689,466,000
Preferred Stock	172,118,000	214,262,000
Total shareholders’ equity	408,010,000	387,634,000
Total Liabilities and Shareholders’ Equity	2,251,531,000	2,457,063,000
Combined Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Total current assets	105,225,000	105,533,000
Total property and equipment, net	2,395,752,000	2,630,707,000
Investment in subsidiaries	0	0
Other assets	9,546,000	10,346,000
Total Assets	2,510,523,000	2,746,586,000
Current liabilities	3,329,846,000	3,631,401,000
Long-term liabilities	65,642,000	114,978,000
Preferred Stock	0	0
Total shareholders’ equity	(884,965,000)	(999,793,000)
Total Liabilities and Shareholders’ Equity	2,510,523,000	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 Finan71

Condensed Consolidating Financial Information (Schedule Of Condensed Consolidating Statement Of Operations) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Condensed Income Statements, Captions [Line Items]
Total revenues	$ 225,280,000	$ 151,355,000
Total costs and expenses	197,469,000	111,334,000
Income (loss) before income taxes	27,811,000	40,021,000
Income tax (expense) benefit	(319,000)	0
Equity (deficit) in income of subsidiaries	0	0
Net Income (loss)	27,492,000	40,021,000
Dividends on preferred stock	(4,863,000)	0
Accretion on preferred stock	(753,000)	0
Loss on redemption of preferred stock	(7,133,000)	0
Net Income Attributable to Common Shareholders	14,743,000	40,021,000
Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Total revenues	0	0
Total costs and expenses	(9,000)	10,000
Income (loss) before income taxes	9,000	(10,000)
Income tax (expense) benefit	0	0
Equity (deficit) in income of subsidiaries	(114,828,000)	(58,817,000)
Net Income (loss)	(114,819,000)	(58,827,000)
Dividends on preferred stock	0	0
Accretion on preferred stock	0	0
Loss on redemption of preferred stock	0	0
Net Income Attributable to Common Shareholders	(114,819,000)	(58,827,000)
Parent Company [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Total revenues	20,000	82,000
Total costs and expenses	87,365,000	18,868,000
Income (loss) before income taxes	(87,345,000)	(18,786,000)
Income tax (expense) benefit	0	0
Equity (deficit) in income of subsidiaries	114,828,000	58,817,000
Net Income (loss)	27,483,000	40,031,000
Dividends on preferred stock	4,863,000	0
Accretion on preferred stock	(753,000)	0
Loss on redemption of preferred stock	(7,133,000)	0
Net Income Attributable to Common Shareholders	14,734,000	40,031,000
Combined Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Total revenues	225,260,000	151,273,000
Total costs and expenses	110,113,000	92,456,000
Income (loss) before income taxes	115,147,000	58,817,000
Income tax (expense) benefit	(319,000)	0
Equity (deficit) in income of subsidiaries	0	0
Net Income (loss)	114,828,000	58,817,000
Dividends on preferred stock	0	0
Accretion on preferred stock	0	0
Loss on redemption of preferred stock	0	0
Net Income Attributable to Common Shareholders	114,828,000	58,817,000
Combined Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Total revenues	0	0
Total costs and expenses	0	0
Income (loss) before income taxes	0	0
Income tax (expense) benefit	0	0
Equity (deficit) in income of subsidiaries	0	0
Net Income (loss)	0	0
Dividends on preferred stock	0	0
Accretion on preferred stock	0	0
Loss on redemption of preferred stock	0	0
Net Income Attributable to Common Shareholders	$ 0	$ 0

Condensed Consolidating Finan72

Condensed Consolidating Financial Information (Schedule Of Condensed Consolidating Statement Of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	$ 138,724	$ 76,408
Net cash provided by (used in) investing activities	107,587	(113,826)
Net cash provided by (used in) financing activities	(250,966)	35,615
Net Decrease in Cash and Cash Equivalents	(4,655)	(1,803)
Cash and Cash Equivalents, Beginning of Period	9,540	4,194
Cash and Cash Equivalents, End of Period	4,885	2,391
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	(334,963)	(9,493)
Net cash provided by (used in) financing activities	334,963	9,493
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	(88,377)	(47,297)
Net cash provided by (used in) investing activities	334,688	9,879
Net cash provided by (used in) financing activities	(250,966)	35,615
Net Decrease in Cash and Cash Equivalents	(4,655)	(1,803)
Cash and Cash Equivalents, Beginning of Period	9,540	4,194
Cash and Cash Equivalents, End of Period	4,885	2,391
Combined Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	227,101	123,705
Net cash provided by (used in) investing activities	107,862	(114,212)
Net cash provided by (used in) financing activities	(334,963)	(9,493)
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 Inform73

Supplemental Cash Flow Information (Supplemental Cash Flow Disclosures) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Supplemental Cash Flow Elements [Abstract]
Interest Paid, Net	$ 14,855	$ 19,480
Change in capital expenditure payables and accruals	(9,677)	28,139
Contingent Consideration, Liability, Acquisition Date Fair Value	$ (7,880)	$ 0

Subsequent Events (Narrative) (

Subsequent Events (Narrative) (Details) - USD ($)	1 Months Ended	2 Months Ended	3 Months Ended
	May 31, 2018	Jun. 30, 2018	Mar. 31, 2018	May 04, 2018	May 03, 2018	Dec. 31, 2017
Senior Secured Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Current Borrowing Capacity			$ 830,000,000			$ 900,000,000
Line of Credit Facility, Elected Borrowing Capacity			$ 800,000,000
Senior Secured Revolving Credit Facility [Member] | Less than 25 percent [Member]
Subsequent Event [Line Items]
Margin for eurodollar loans			2.00%
Senior Secured Revolving Credit Facility [Member] | Greater than or equal to 90 percent [Member]
Subsequent Event [Line Items]
Margin for eurodollar loans			3.00%
Subsequent Event [Member] | Other Long Term Debt [Member]
Subsequent Event [Line Items]
Debt Instrument, Interest Rate, Stated Percentage					4.375%
Cash paid for debt redemption	$ 4,500,000
Debt Instrument, Repurchased Face Amount					$ 4,400,000
Redemption price, percentage of principal amount					100.00%
Accrued interest paid associated with redemption of debt	$ 100,000
Subsequent Event [Member] | Senior Secured Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Current Borrowing Capacity				$ 1,000,000,000
Line of Credit Facility, Elected Borrowing Capacity				$ 900,000,000
Subsequent Event [Member] | Senior Secured Revolving Credit Facility [Member] | Maximum [Member]
Subsequent Event [Line Items]
Margin for eurodollar loans		2.50%
Subsequent Event [Member] | Senior Secured Revolving Credit Facility [Member] | Minimum [Member]
Subsequent Event [Line Items]
Margin for eurodollar loans		1.50%

Subsequent Events, Derivative I

Subsequent Events, Derivative Instruments (Schedule of Crude Oil Derivative Positions) (Details) - Subsequent Event [Member] - Crude Oil	Apr. 23, 2018bbl / d$ / bbls	Apr. 05, 2018bbl / d$ / bbls
Basis Swaps | 1H 2019 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d		2,500
Weighted Average Fixed Price ($/Bbl)		(4)
Basis Swaps | 2H 2019 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d		3,000
Weighted Average Fixed Price ($/Bbl)		(4)
Three-way Collars | FY 2019 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	3,000
Weighted Average Sub-Floor Price ($/Bbls)	45
Weighted Average Floor Price ($/Bbls)	55
Weighted Average Ceiling Price ($/Bbls)	71.21