Antero Midstream (AM) 10-K 13 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2018	Feb. 08, 2019	Jun. 29, 2018
Document and Entity Information
Entity Registrant Name	Antero Midstream GP LP
Entity Central Index Key	1,623,925
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 1.4
Entity Common Stock, Shares Outstanding		186,235,845
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash	$ 2,822	$ 5,987
Prepaid expenses and other current assets	87
Total current assets	2,909	5,987
Investment in Antero Midstream Partners LP	43,492	23,772
Deferred tax asset	1,304
Total assets	47,705	29,759
Current liabilities:
Accounts payable–affiliate	731	57
Accounts payable and accrued liabilities	435	236
Taxes payable	15,678	13,858
Total current liabilities	16,844	14,151
Partners' capital:
Common shareholders - public (186,181, 975 shares and 186,219,438 shares issued and outstanding at December 31, 2017 and 2018, respectively)	(41,969)	(19,866)
IDR LLC Series B units (32,875 and 65,745 units vested at December 31, 2017 and 2018, respectively)	72,830	35,474
Total partners' capital	30,861	15,608
Total liabilities and partners' capital	$ 47,705	$ 29,759

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - shares	Dec. 31, 2018	Dec. 31, 2017
Consolidated Balance Sheets
Partner’ capital, shares issued	186,219,438	186,181,975
Partner’ capital, shares outstanding	186,219,438	186,181,975
IDR LLC Series B units vested	65,745	32,875

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Consolidated Statements of Operations and Comprehensive Income
Equity in earnings of Antero Midstream Partners LP	$ 142,906	$ 69,720	$ 16,944
Total income	142,906	69,720	16,944
General and administrative expense	8,740	6,201	814
Equity-based compensation	35,111	34,933
Total operating expenses	43,851	41,134	814
Operating income	99,055	28,586	16,130
Interest expense, net	(136)
Income before income taxes	98,919	28,586	16,130
Provision for income taxes	(32,311)	(26,261)	(6,419)
Net income and comprehensive income	66,608	2,325	$ 9,711
Net income attributable to vested Series B units	(5,236)	(784)
Pre-IPO net income attributed to parent		4,939
Net income attributable to common shareholders	$ 61,372	$ 6,480
Net income per common share - basic and diluted	$ 0.33	$ 0.03
Weighted average number of common shares outstanding - basic and diluted	186,203	186,176

Consolidated Statements of Part

Consolidated Statements of Partners' Capital - USD ($) $ in Thousands	Common Shares Representing Limited Partner Interests	Antero Resources Midstream Management LLC Members' Equity	Series B Unitholders	Total
Balance at Dec. 31, 2015		$ 558		$ 558
Partners' Capital
Net income and comprehensive income		9,711		9,711
Balance at Dec. 31, 2016		10,269		10,269
Partners' Capital
Net income and comprehensive income				2,325
Pre-IPO net loss and comprehensive loss		(4,939)		(4,939)
Pre-IPO equity-based compensation		10,237		10,237
Conversion of Antero Resources Midstream Management LLC to a limited partnership	$ 15,567	$ (15,567)
Post-IPO net income and comprehensive income	6,480		$ 784	7,264
Equity-based compensation	24,696			24,696
Distributions to Antero Resources Investment LLC	(15,908)			(15,908)
Distributions to shareholders	(16,011)			(16,011)
Vesting of Series B units	(34,690)		34,690
Balance at Dec. 31, 2017	(19,866)		35,474	15,608
Partners' Capital
Net income and comprehensive income	61,372		5,236	66,608
Equity-based compensation	35,111			35,111
Distributions to shareholders	(84,166)			(84,166)
Distributions to Series B unitholders			(2,300)	(2,300)
Vesting of Series B units	(34,420)		34,420
Balance at Dec. 31, 2018	$ (41,969)		$ 72,830	$ 30,861

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows provided by operating activities:
Net income	$ 66,608	$ 2,325	$ 9,711
Adjustment to reconcile net income to net cash provided by operating activities:
Equity in earnings of Antero Midstream Partners LP	(142,906)	(69,720)	(16,944)
Distributions received from Antero Midstream Partners LP	123,186	53,491	10,370
Amortization of deferred financing costs	148
Equity-based compensation	35,111	34,933
Deferred income taxes	(1,304)		(368)
Changes in current assets and liabilities:
Prepaid expenses and other current assets	(5)
Accounts receivable - related party			(217)
Accounts payable-affiliate	674	57
Accounts payable and accrued liabilities	199	(190)	426
Taxes payable	1,820	7,184	6,559
Net cash provided by operating activities	83,531	28,080	9,537
Cash flows used in financing activities:
Distributions to Antero Resources Investment LLC		(15,691)
Distributions to shareholders	(84,166)	(16,011)
Distributions to Series B unitholders	(2,300)
Payments of deferred financing costs	(230)
Net cash used in financing activities	(86,696)	(31,702)
Net increase (decrease) in cash	(3,165)	(3,622)	9,537
Cash, beginning of period	5,987	9,609	72
Cash, end of period	2,822	5,987	9,609
Supplemental disclosure of cash flow information:
Cash paid during the period for taxes	$ (31,795)	$ (19,077)	$ (228)

Business and Organization

Business and Organization	12 Months Ended
	Dec. 31, 2018
Business and Organization
Business and Organization	(1) Business and Organization (a) Antero Midstream GP LP (“AMGP”) was originally formed as Antero Resources Midstream Management LLC (“ARMM”) in 2013 to become the general partner of Antero Midstream Partners LP (“Antero Midstream”), a master limited partnership that is publicly traded on the New York Stock Exchange (NYSE: AM). On May 4, 2017, ARMM converted from a Delaware limited liability company to a Delaware limited partnership and changed its name to Antero Midstream GP LP in connection with its initial public offering (“IPO”). Unless the context otherwise requires, references to “we” and “our” refer to: (i) for the period prior to May 4, 2017, ARMM, and (ii) beginning on May 4, 2017, AMGP. AMGP owns 100% of the membership interests of Antero Midstream Partners GP LLC (“AMP GP”), which owns the non-economic general partner interest in Antero Midstream, and AMGP owns all of the Series A capital interests (“Series A Units”) in Antero IDR Holdings LLC (“IDR LLC”), which owns the incentive distribution rights (“IDRs”) in Antero Midstream. IDR LLC also has Series B profits interests (“Series B Units”) outstanding that entitle the holders to receive up to 6% of the distributions that Antero Midstream makes on the IDRs in excess of $7.5 million per quarter, subject to certain vesting conditions (see Note 5—Long-Term Incentive Plans). AMGP is taxed as a corporation for U.S. federal income tax purposes and AMGP refers to its outstanding limited partner interests as common shares. AMGP’s only income results from distributions made on the IDRs of Antero Midstream. The Antero Midstream IDRs entitle holders to receive cash distributions from Antero Midstream when distributions exceed certain target amounts (see Note 6—Distributions from Antero Midstream). AMGP is managed by its general partner, AMGP GP LLC (“AMGP GP”), which establishes the quarterly cash distribution for AMGP’s common shares payable to shareholders. AMGP GP has a board of directors appointed by certain former members of Antero Resources Investment LLC (“Antero Investment”), the former sole member of ARMM prior to its liquidation on October 31, 2017. Following the completion of our IPO, certain of AMGP’s directors and executive officers own AMGP common shares as well as Series B Units in IDR LLC. In addition, certain of AMGP’s directors and executive officers own a portion of Antero Resources Corporation’s (“Antero Resources”) (NYSE: AR) common stock and Antero Midstream’s common units. AMGP has an agreement with Antero Resources, under which Antero Resources provides general and administrative services to AMGP for a fee of $0.5 million per year, subject to annual inflation adjustments. AMGP also incurs recurring direct expenses for the costs associated with being a publicly traded entity. Antero Midstream was formed by Antero Resources to own, operate and develop midstream energy assets to service Antero Resources’ oil and gas producing assets. Both Antero Midstream and Antero Resources’ assets are located in the Marcellus Shale and Utica Shale located in West Virginia and Ohio. Antero Midstream’s assets consist of gathering pipelines, compressor stations, interests in processing and fractionation plants, and water handling and treatment assets, which provide midstream services to Antero Resources under long term, fixed fee contracts. Antero Midstream also has a 15% equity interest in the gathering system of Stonewall Gas Gathering LLC (“Stonewall”) and a 50% equity interest in a joint venture to develop processing and fractionation assets with MarkWest Energy Partners, L.P. AMGP’s results of operations, financial position and cash flows are dependent on the results of operations, financial position and cash flows of Antero Midstream. As a result, these consolidated financial statements should be read in conjunction with Antero Midstream’s audited consolidated financial statements and notes thereto presented in its Annual Report on Form 10‑K for the year ended December 31, 2018. (b) On October 9, 2018, Antero Midstream, Antero Midstream GP LP (“AMGP”) and certain of their affiliates entered into a Simplification Agreement (as may be amended from time to time, the “Simplification Agreement”), pursuant to which, among other things, (1) AMGP will be converted from a limited partnership to a corporation under the laws of the State of Delaware, to be named Antero Midstream Corporation (which is referred to as “New AM” and the conversion, the “Conversion”); (2) an indirect, wholly owned subsidiary of New AM will be merged with and into Antero Midstream, with Antero Midstream surviving the merger as an indirect, wholly owned subsidiary of New AM (the “Merger”) and (3) all the issued and outstanding Series B Units representing limited liability company interests of Antero IDR Holdings LLC (“IDR Holdings”), a partially owned subsidiary of AMGP and the holder of all of Antero Midstream’s incentive distribution rights, will be exchanged for an aggregate of approximately 17.35 million shares of New AM’s Common Stock (the “Series B Exchange”). The Conversion, the Merger, the Series B Exchange and the other transactions contemplated by the Simplification Agreement are collectively referred to as the “Transactions.” As a result of the Transactions, Antero Midstream will be a wholly owned subsidiary of New AM and former shareholders of AMGP, unitholders of Antero Midstream and holders of Series B Units will each own New AM’s Common Stock. If the Transactions are completed, (1) each holder of Antero Midstream’s common units other than Antero Resources (the “AM Public Unitholders”), will be entitled to receive, at its election, one of (i) $3.415 in cash without interest and 1.6350 validly issued, fully paid, nonassessable shares of New AM’s Common Stock for each of Antero Midstream’s common units held (the “Public Mixed Consideration”); (ii) 1.6350 shares of New AM’s Common Stock plus an additional number of shares of New AM’s Common Stock equal to the quotient of (A) $3.415 and (B) the average of the 20-day volume-weighted average trading price per AMGP common share prior to the final election day for AM Public Unitholders (the “AMGP VWAP”), for each of Antero Midstream’s common units held (the “Public Stock Consideration”); or (iii) $3.415 in cash plus an additional amount of cash equal to the product of (A) 1.6350 and (B) the AMGP VWAP for each of Antero Midstream’s common units held (the “Public Cash Consideration”); and (2) in exchange for each of the Partnership’s common units held, Antero Resources will be entitled, subject to certain adjustments (as described below), to receive $3.00 in cash without interest and 1.6023 validly issued, fully paid, nonassessable shares of New AM’s Common Stock for each of Antero Midstream’s common units held by Antero Resources (the “AR Mixed Consideration”). The aggregate cash consideration to be paid to Antero Resources and the AM Public Unitholders will be fixed at an amount equal to the aggregate amount of cash that would have been paid and issued if all AM Public Unitholders received $3.415 in cash per common unit (the “Available Cash”) and Antero Resources received $3.00 in cash per common unit, which is approximately $598 million. If the Available Cash exceeds the cash consideration elected to be received by the AM Public Unitholders, Antero Resources may elect to increase the total amount of cash consideration to be received as a part of the AR Mixed Consideration up to an amount equal to the excess and the amount of shares it will receive will be reduced accordingly based on the AMGP VWAP. In addition, the consideration to be received each AM Public Unitholder may be prorated in the event that more cash or equity is elected to be received than what would otherwise have been paid if all AM Public Unitholders had received the Public Mixed Consideration and Antero Resources received the AR Mixed Consideration. The Merger should be a taxable event for Antero Midstream’s unitholders. The amount and character of gain or loss recognized by each unitholder in the Merger will vary depending on such unitholder’s particular situation, including the value of the shares of New AM’s Common Stock, if any, received by such unitholder, the amount of any cash received by such unitholder, the adjusted tax basis of such unitholder’s common units (and any changes to such tax basis as a result of Antero Midstream’s allocations of income, gain, loss and deduction to such unitholder for the taxable year that includes the Merger), and the amount of any suspended passive losses that may be available to such unitholder to offset a portion of the gain recognized by such unitholder in connection with the Merger. Special meetings of AMGP shareholders and Antero Midstream unitholders will be held on March 8, 2019 to vote on the Simplification Agreement, the Merger and the other Transactions contemplated thereby, as applicable, and all AMGP shareholders and Antero Midstream unitholders of record as of the close of business on January 11, 2019, which is the record date for the special meetings, will be entitled to vote the AMGP common shares and Antero Midstream common units, respectively, owned by them on the record date. AMGP and Antero Midstream expect the Transactions to close shortly after the special meeting date, subject to certain closing conditions under the documentation for the Transactions. AMGP and Antero Midstream expect to fund the cash portion of the merger consideration with borrowings under Antero Midstream’s revolving credit facility. The revolving credit facility was amended on October 31, 2018 to increase lender commitments from $1.5 billion to $2.0 billion. Also on October 9, 2018, in connection with the entry into the Simplification Agreement, (1) Antero Midstream entered into a voting agreement with AMGP’s shareholders owning a majority of the outstanding AMGP common shares, pursuant to which, among other things, such shareholders agreed to vote in favor of the Transactions, (2) AMGP entered into a voting agreement with Antero Resources, pursuant to which, among other things, Antero Resources agreed to vote in favor of the Transactions and (3) AMGP, Antero Resources, certain funds affiliated with Warburg Pincus LLC and Yorktown Partners LLC (together, the “Sponsor Holders”), Paul M. Rady and Glen C. Warren, Jr. (Messrs. Rady and Warren together, the “Management Stockholders”) entered into a Stockholders’ Agreement, pursuant to which, among other things, Antero Resources, the Sponsor Holders and the Management Holders will have the ability to designate members of the New AM board of directors under certain circumstances, effective as the closing of the Transactions.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	(2) Summary of Significant Accounting Policies (a) The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”). In the opinion of management, the accompanying consolidated financial statements include all adjustments (consisting of normal and recurring accruals) considered necessary to present fairly AMGP’s financial position as of December 31, 2017 and 2018, and AMGP’s results of operations and cash flows for the years ended December 31, 2016, 2017 and 2018. AMGP has no items of other comprehensive income; therefore, AMGP’s net income is identical to its comprehensive income. As of the date these consolidated financial statements were filed with the SEC, AMGP completed its evaluation of potential subsequent events for disclosure and no items requiring disclosure were identified other than as disclosed in Note 7—Cash Distributions. (b) The consolidated financial statements include the accounts of AMGP, AMP GP (its wholly-owned subsidiary), and IDR LLC. (c) AMGP has determined that Antero Midstream is a variable interest entity (“VIE”) for which AMGP is not the primary beneficiary and therefore does not consolidate. AMGP concluded that Antero Resources is the primary beneficiary of Antero Midstream and should consolidate its financial results. Antero Resources is the primary beneficiary based on its power to direct the activities that most significantly impact Antero Midstream’s economic performance and its obligations to absorb losses or receive benefits of Antero Midstream that could be significant to Antero Midstream. Antero Resources owns approximately 52.8% of the outstanding limited partner interests in Antero Midstream and its officers and management group also act as management of Antero Midstream. Antero Midstream was formed to own, operate and develop midstream energy assets to service Antero Resources’ production under long-term contracts as described herein. AMGP does not own any limited partnership interests in Antero Midstream and have no capital interests in Antero Midstream. AMGP has not provided, and does not anticipate providing, financial support to Antero Midstream. AMGP’s ownership of the non-economic general partner interest in Antero Midstream provides AMGP with significant influence over Antero Midstream, but not control over the decisions that most significantly impact the economic performance of Antero Midstream. AMGP’s indirect ownership of the IDRs of Antero Midstream entitles AMGP to receive cash distributions from Antero Midstream when distributions exceed certain target amounts. AMGP’s ownership of these interests does not require AMGP to provide financial support to Antero Midstream. AMGP obtained these interests upon its formation for no consideration. Therefore, they have no cost basis and are classified as long term investments. AMGP’s share of Antero Midstream’s earnings as a result of AMGP’s ownership of the IDRs is accounted for using the equity method of accounting. AMGP recognizes distributions earned from Antero Midstream as “Equity in earnings of Antero Midstream Partners LP” on its statement of operations in the period in which they are earned and are allocated to AMGP’s capital account. AMGP’s long-term interest in the IDRs on the balance sheet is recorded in “Investment in Antero Midstream Partners LP.” The ownership of the general partner interests and IDRs do not provide AMGP with any claim to the assets of Antero Midstream other than the balance in its Antero Midstream capital account. Income related to the IDRs is recognized as earned and increases AMGP’s capital account and equity investment. When these distributions are paid to AMGP, they reduce its capital account and its equity investment in Antero Midstream. See Note 6—Distributions from Antero Midstream. (d) The preparation of the consolidated financial statements and notes in conformity with GAAP requires that management formulate estimates and assumptions that affect income, expenses, assets, and liabilities. Changes in facts and circumstances or discovery of new information may result in revised estimates, and actual results could differ from those estimates. (e) AMGP is a Delaware limited partnership that is taxed as a corporation for U.S. federal income tax purposes. AMGP recognizes deferred tax assets and liabilities for temporary differences resulting from net operating loss carryforwards for income tax purposes and the differences between the financial statement and tax basis of assets and liabilities. The effect of changes in tax laws or tax rates is recognized in income during the period such changes are enacted. Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more likely than not that some portion, or all, of the deferred tax assets will not be realized. AMGP regularly reviews its tax positions in each significant taxing jurisdiction during the process of evaluating its tax provision. AMGP makes adjustments to its tax provision when: (i) facts and circumstances regarding a tax position change, causing a change in management’s judgment regarding that tax position; and/or (ii) a tax position is effectively settled with a tax authority at a differing amount. (f) General and administrative costs incurred during 2016 and pre-IPO in 2017 primarily relate to legal and other costs incurred in connection with AMGP’s IPO. Post-IPO general and administrative expense consists primarily of management fees paid to Antero Resources, and other legal and administrative expenses. Additionally, in connection with the formation of a conflicts committee of the board of directors of the Partnership’s general partner to consider potential transactions involving us in connection with Antero Resources’ and Antero Midstream’s efforts to explore, review, and evaluate potential measures related to its valuation, the conflicts committee retained an investment advisor and attorneys. Attorneys’ fees related to this matter are charged to expense as incurred. For the year ended December 31, 2018, the AMGP has expensed $6.9 million related to conflicts committee expenses. (g) AMGP recognizes compensation cost related to all equity-based awards in the financial statements based on their estimated grant date fair value. AMGP has authorized and outstanding Series B Units and AMGP is authorized to grant common share awards. The grant date fair values are determined based on the type of award and may utilize market prices on the date of grant or a Monte Carlo simulation, as appropriate for the type of equity-based award. Compensation cost is recognized ratably over the applicable vesting or service period. Forfeitures are accounted for as they occur by reversing the expense previously recognized for awards that were forfeited during the period. See Note 5—Long-Term Incentive Plans for additional information regarding our equity-based compensation. (h ) Measures The Financial Accounting Standards Board (the “FASB”) Accounting Standards Codification Topic 820, Fair Value Measurements and Disclosures , clarifies the definition of fair value, establishes a framework for measuring fair value, and expands disclosures about fair value measurements. This guidance also relates to all nonfinancial assets and liabilities that are not recognized or disclosed on a recurring basis (e.g., the initial recognition of asset retirement obligations and impairments of long‑lived assets). The fair value is the price that AMGP estimates would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. A fair value hierarchy is used to prioritize inputs to valuation techniques used to estimate fair value. An asset or liability subject to the fair value requirements is categorized within the hierarchy based on the lowest level of input that is significant to the fair value measurement. AMGP’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability. The highest priority (Level 1) is given to unadjusted quoted market prices in active markets for identical assets or liabilities, and the lowest priority (Level 3) is given to unobservable inputs. Level 2 inputs are data, other than quoted prices included within Level 1, which are observable for the asset or liability, either directly or indirectly. (i) Net Income per Common Share Net income per common share–basic for each period is computed by dividing n et income attributable to common shareholders by the basic weighted average number of common shares outstanding during the period. Net income per common share – diluted for each period is computed after giving consideration to the potential dilution from outstanding Series B units, calculated using the if converted method. During the periods in which AMGP incurs a net loss, diluted weighted average shares outstanding are equal to basic weighted average common shares outstanding because the effect of all equity awards is anti-dilutive. At December 31, 2017 and 2018, there were 4,777,759 and 1,365,525 shares, respectively, to be issued upon assumed conversion of the Series B Units. The effect of these awards is anti-dilutive for 2017 and 2018, and thus, AMGP’s diluted net income per common share for the years ended December 31, 2017 and 2018 is equal to our basic net income per common share. (j) On June 20, 2018, the FASB issued Accounting Standards Update (“ASU”) No. 2018-07, Improvements to Nonemployee Share-Based Payment Accounting , which aligns the accounting for employee and nonemployee share-based payments. AMGP elected to adopt the standard as of October 1, 2018. As a result of adopting this standard, AMGP reclassified its $3.0 million liability for equity-based compensation to partners’ capital as of as of October 1, 2018. See Note 5—Long-Term Incentive Plans.

Credit Facility

Credit Facility	12 Months Ended
	Dec. 31, 2018
Credit Facility
Credit Facility	(3) Credit Facility On May 9, 2018, AMGP entered into a credit facility (the “Credit Facility”) with a bank, which provides for a line of credit of up to $12 million. The maturity date of the Credit Facility is May 6, 2019. The Credit Facility is guaranteed by IDR LLC and secured by a pledge of the Series A capital interests in IDR LLC and the membership interests in AMP GP. Interest is payable on borrowings at a variable rate based on the base rate plus a margin rate of interest equal to 1.00% per annum. The base rate is the highest of (i) the Federal Funds Rate plus ½ of 1%, (ii) the rate of interest in effect for such day as publicly announced from time to time by the Lender as its “prime rate” and (iii) the Eurodollar Rate plus 1.00%. The Credit Facility contains customary events of default and various affirmative and negative covenants, including restrictions on incurring indebtedness, making investments and disposing of assets, and a requirement to completely repay amounts outstanding under the line of credit at least once each fiscal quarter. At December 31, 2018, AMGP had no borrowings under the Credit Facility.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Taxes
Income Taxes	(4) Income Taxes For the years ended December 31, 2016, 2017, and 2018, income tax expense consisted of the following: Year Ended December 31, (in thousands) 2016 2017 2018 Current income tax expense $ 6,787 26,261 33,615 Deferred income tax benefit (368) — (1,304) Total income tax expense $ 6,419 26,261 32,311 Income tax expense differs from the amount that would be computed by applying the U.S. statutory federal income tax rate of 35% to income` for the years ended December 31, 2016 and 2017, and 21% for the year ended December 31, 2018, as a result of the following: Year Ended December 31, (in thousands) 2016 2017 2018 Federal income tax expense $ 5,646 10,005 20,773 State income tax expense, net of federal benefit 479 952 4,133 Non-deductible equity-based compensation — 13,296 8,087 Non-deductible IPO expenses 309 1,948 1 Other (15) 60 (683) Provision for income taxes $ 6,419 26,261 32,311 Deferred income taxes reflect the impact of temporary differences between assets and liabilities for financial reporting purposes and such amounts as measured by tax laws. As of December 31, 2018, AMGP had a deferred tax asset of $1.3 million related to transaction costs incurred for the Simplification Agreement. In assessing the realizability of deferred tax assets, management considers whether some portion or all of the deferred tax assets will be realized based on a more-likely-than-not standard of judgment. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which the AMGP’s temporary differences become deductible. Management considers projected future taxable income and tax planning strategies in making this assessment. Based upon the projections of future taxable income over the periods in which the deferred tax assets are deductible, management believes that the Partnership will realize the benefits of these deductible differences and thus has not recorded a valuation allowance. The tax years 2015 through 2018 remain open to examination by the U.S. Internal Revenue Service. The Company and its subsidiaries file tax returns with various state taxing authorities; these returns remain open to examination for tax years 2014 through 2018.

Long-Term Incentive Plans

Long-Term Incentive Plans	12 Months Ended
	Dec. 31, 2018
Long-Term Incentive Plans
Long-Term Incentive Plans	(5) Long-Term Incentive Plans As of December 31, 2018, IDR LLC has 98,600 Series B Units authorized and outstanding that entitle the holders to receive up to 6% of the amount of the distributions that Antero Midstream makes on its IDRs in excess of $7.5 million per quarter, subject to certain vesting conditions. During the year ending December 31, 2017, 1,400 Series B Units were forfeited and there were no forfeitures during 2018. The Series B Units vest ratably over a three year period. On December 31, 2018, 65,745 Series B Units were vested. The holders of vested Series B Units have the right to convert the units to common shares with a value equal to their pro rata share of up to 6% of any increase in AMGP’s equity value in excess of $2.0 billion. In no event will the aggregate number of newly issued common shares exceed 6% of the total number of AMGP’s issued and outstanding common shares. AMGP recognizes expense for the grant date fair value of the awards over the vesting period of the awards. Forfeitures are accounted for as they occur by reversing expense previously recognized for awards that were forfeited during the period. For awards granted to common law employees, the grant date fair value of the Series B Unit awards was estimated using a Monte Carlo simulation using various assumptions including a floor equity value of $2.0 billion, expected volatility of 43% based on historical volatility of a peer group of publicly traded partnerships, a risk free rate of 2.45%, and expected IDR distributions based on internal estimates discounted based on a weighted average cost of capital assumption of 7.25%. Based on these assumptions, the estimated value of each Series B Unit was $999 when they were issued. The fair value measurement is based on significant inputs not observable in the market and thus represents a Level 3 measurement within the fair value hierarchy. For a discussion of the Series B Exchange in the event that the Transactions are consummated, see Note 1—Business and Organization. Prior to October 1, 2018, certain of the awards made to non-common law employees were accounted for as liability awards. On October 1, 2018, AMGP adopted ASU 2018-07, which allows these awards to be treated in the same manner as employee awards. The remaining liability at September 30, 2018 of $3.0 million was reclassified to equity effective October 1, 2018. The remaining unamortized expense related to these awards will be amortized from October 1, 2018 through December 31, 2019. Forfeitures are accounted for as they occur by reversing expense previously recognized for awards that were forfeited during the period. At September 30, 2018, the fair value of the Series B Unit awards was estimated using a Monte Carlo simulation using various assumptions including an equity value of $3.3 billion, expected volatility of 38% based on historical volatility of a peer group of publicly traded partnerships, a risk free rate of 3.00%, and expected IDR distributions based on internal estimates discounted based on a weighted average cost of capital assumption of 7.25%. Based on these assumptions, the estimated value of each Series B Unit at September 30, 2018 was $1 , 673. The fair value measurement is based on significant inputs not observable in the market and thus represents a Level 3 measurement within the fair value hierarchy. AMGP recognized expense related to the Series B Unit awards of $34.7 million and $34.4 million during the years ended December 31, 2017 and 2018, respectively. As of December 31, 2018, there was $34.4 million of unamortized compensation expense related to unvested Series B Units that is expected to be recognized in 2019. On April 17, 2017, AMGP also adopted the Antero Midstream GP LP Long-Term Incentive Plan (“AMGP LTIP”), pursuant to which certain non-employee directors of AMGP’s general partner and certain officers, employees and consultants of Antero Resources are eligible to receive awards representing equity interests in AMGP. An aggregate of 930,851 common shares may be delivered pursuant to awards under the AMGP LTIP, subject to customary adjustments. As of December 31, 2017 and 2018, 11,762 and 49,225 common shares were granted, respectively. AMGP recognized related expense of $0.2 million and $0.7 million related to these awards for the years ended December 31, 2017 and 2018, respectively. As of December 31, 2018, 881,626 common shares remain available for grant under the AMGP LTIP.

Distributions from Antero Midst

Distributions from Antero Midstream	12 Months Ended
	Dec. 31, 2018
Distributions from Antero Midstream
Distributions from Antero Midstream	(6) Distributions from Antero Midstream Antero Midstream’s partnership agreement provides for a minimum quarterly distribution of $0.17 per common unit for each quarter, or $0.68 per unit on an annualized basis. If cash distributions to Antero Midstream’s unitholders exceed $0.1955 per common unit in any quarter, IDR LLC, as the holder of Antero Midstream’s IDRs, will receive distributions according to the following percentage allocations: Marginal Percentage Interest in Distributions Total Quarterly Distribution Antero Midstream Common Unitholders Holder of IDRs above $0.1955 up to $0.2125 85 % 15 % above $0.2125 up to $0.2550 75 % 25 % above $0.2550 50 % 50 % Distributions per common unit and distributions related to the IDRs were as follows for the periods indicated: Quarter Distribution Date Antero Midstream Distribution Amount Income Attributable to IDRs Q1 2016 May 25, 2016 $ $ 1,850 Q2 2016 August 24, 2016 $ $ 2,731 Q3 2016 November 24, 2016 $ $ 4,820 Q4 2016 February 8, 2017 $ $ 7,543 Q1 2017 May 10, 2017 $ $ 11,553 Q2 2017 August 16, 2017 $ $ 15,328 Q3 2017 November 16, 2017 $ $ 19,067 Q4 2017 February 13, 2018 $ $ 23,772 Q1 2018 May 18, 2018 $ $ 28,460 Q2 2018 August 17, 2018 $ $ 33,138 Q3 2018 November 16, 2018 $ $ 37,816 The board of directors of Antero Midstream’s general partner has declared a cash distribution of $0.47 per unit for the quarter ended December 31, 2018. The distribution was paid on February 13, 2019 to shareholders of record as of February 1, 2019. The distribution attributable to the IDRs for the quarter ended December 31, 2018 is $43.5 million. Distributions attributable to the IDRs which relate to periods prior to May 9, 2017, the closing of our IPO, were distributed to Antero Investment prior to its liquidation.

Cash Distributions

Cash Distributions	12 Months Ended
	Dec. 31, 2018
Cash Distributions
Cash Distributions	(7 ) Cash Distributions The following table details the amount of quarterly distributions AMGP paid with respect to the quarter indicated (in thousands, except per share data): Distributions Quarter Record Date Distribution Date Common shareholders Antero Resources Investment Total Distributions per common share * May 9, 2017 September 13, 2017 $ — 15,908 15,908 * Q2 2017 August 3, 2017 August 23, 2017 5,026 — 5,026 $ Q3 2017 November 1, 2017 November 23, 2017 10,985 — 10,985 $ Total 2017 $ 16,011 15,908 31,919 Q4 2017 February 1, 2018 February 20, 2018 $ 13,964 — 13,964 $ Q1 2018 May 3, 2018 May 23, 2018 20,109 — 20,109 $ Q2 2018 August 2, 2018 August 22, 2018 23,276 — 23,276 $ Q3 2018 November 2, 2018 November 21, 2018 26, 817 — 26,817 $ Total 2018 $ 84,166 — 84,166 * Income relating to periods prior to May 9, 2017, the closing of our IPO, was distributed to Antero Investment prior to its liquidation. The board of directors of our general partner has declared a cash distribution of $0.164 per share for the quarter ended December 31, 2018. The distribution will be payable on February 21, 2019 to our shareholders of record as of February 1, 2019.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2018
Related Party Transactions
Related Party Transactions	(8) Related Party Transactions Certain of AMGP’s shareholders, including members of its executive management group, own a significant interest in AMGP and, either through their representatives or directly, serve as members of the Board of Directors of Antero Resources and the Boards of Directors of the general partners of Antero Midstream and AMGP. These same groups or individuals own common stock in Antero Resources and limited partner interests in Antero Midstream. AMGP’s executive management group also manages the operations and business affairs of Antero Resources and Antero Midstream. For a discussion of the Series B Exchange in the event that the Transactions are consummated, see Note 1—Business and Organization. Accounts payable–affiliate at December 31, 2017 and December 31, 2018 consists of less than $0.1 million and less than $0.8 million, respectively, payable to Antero Resources for general and administrative expenses.

Quarterly Financial Information

Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information (Unaudited)
Quarterly Financial Information (Unaudited)	(9 ) Quarterly Financial Information (Unaudited) Our unaudited quarterly financial information for the years ended December 31, 2017 and 2018 is as follows: First Second Third Fourth (in thousands, except per unit data) quarter quarter quarter quarter Year ended December 31, 2017 Total income $ 11,553 15,328 19,067 23,772 Total operating expenses 10,427 12,834 8,932 8,941 Net income (loss) and comprehensive income (loss) (3,299) (3,261) 2,978 5,907 Net income (loss) attributable to Antero Midstream GP LP subsequent to IPO — (1,621) 2,978 5,907 Net income attributable to Series B units — — — (784) Net income attributable to common shareholders $ — (1,621) 2,978 5,123 Net income (loss) per common share–basic and diluted $ (0.01) 0.02 0.03 Year ended December 31, 2018 Total income $ 28,453 33,145 37,816 43,492 Total operating expenses 9,560 11,509 10,803 11,979 Net income and comprehensive income 12,805 14,387 18,028 21,388 Net income attributable to Series B units (413) (506) (598) (3,719) Net income attributable to common shareholders $ 12,392 13,881 17,430 17,669 Net income per common share–basic and diluted $ 0.07 0.07 0.09 0.10

Summarized Financial Informatio

Summarized Financial Information for Antero Midstream	12 Months Ended
	Dec. 31, 2018
Summarized Financial Information for Antero Midstream
Summarized Financial Information for Antero Midstream	(10) Summarized Financial Information for Antero Midstream Summarized financial information for Antero Midstream, AMGP’s investee accounted for using the equity method of accounting, is included in this note. The following tables present summarized income statement and balance sheet information for Antero Midstream (in thousands). Summarized Antero Midstream Income Statement Information Year Ended December 31, 2016 2017 2018 Revenues $ 590,211 772,497 1,028,522 Operating expenses 332,100 447,819 420,952 Operating income 258,111 324,678 607,570 Net income and comprehensive income 236,703 307,315 585,944 Net income attributable to incentive distribution rights (16,944) (69,720) (142,906) Limited partners' interest in net income $ 219,759 237,595 443,038 Summarized Antero Midstream Balance Sheet Information December 31, 2017 2018 Current assets $ 120,385 138,435 Non-current assets 2,921,824 3,407,982 Current liabilities 121,316 99,686 Non-current liabilities 1,404,424 1,755,223 Partners' capital $ 1,516,469 1,691,508

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Summary of Significant Accounting Policies
Basis of Presentation	(a) The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”). In the opinion of management, the accompanying consolidated financial statements include all adjustments (consisting of normal and recurring accruals) considered necessary to present fairly AMGP’s financial position as of December 31, 2017 and 2018, and AMGP’s results of operations and cash flows for the years ended December 31, 2016, 2017 and 2018. AMGP has no items of other comprehensive income; therefore, AMGP’s net income is identical to its comprehensive income. As of the date these consolidated financial statements were filed with the SEC, AMGP completed its evaluation of potential subsequent events for disclosure and no items requiring disclosure were identified other than as disclosed in Note 7—Cash Distributions.
Principles of Consolidation	(b) The consolidated financial statements include the accounts of AMGP, AMP GP (its wholly-owned subsidiary), and IDR LLC.
Investment in Antero Midstream	(c) AMGP has determined that Antero Midstream is a variable interest entity (“VIE”) for which AMGP is not the primary beneficiary and therefore does not consolidate. AMGP concluded that Antero Resources is the primary beneficiary of Antero Midstream and should consolidate its financial results. Antero Resources is the primary beneficiary based on its power to direct the activities that most significantly impact Antero Midstream’s economic performance and its obligations to absorb losses or receive benefits of Antero Midstream that could be significant to Antero Midstream. Antero Resources owns approximately 52.8% of the outstanding limited partner interests in Antero Midstream and its officers and management group also act as management of Antero Midstream. Antero Midstream was formed to own, operate and develop midstream energy assets to service Antero Resources’ production under long-term contracts as described herein. AMGP does not own any limited partnership interests in Antero Midstream and have no capital interests in Antero Midstream. AMGP has not provided, and does not anticipate providing, financial support to Antero Midstream. AMGP’s ownership of the non-economic general partner interest in Antero Midstream provides AMGP with significant influence over Antero Midstream, but not control over the decisions that most significantly impact the economic performance of Antero Midstream. AMGP’s indirect ownership of the IDRs of Antero Midstream entitles AMGP to receive cash distributions from Antero Midstream when distributions exceed certain target amounts. AMGP’s ownership of these interests does not require AMGP to provide financial support to Antero Midstream. AMGP obtained these interests upon its formation for no consideration. Therefore, they have no cost basis and are classified as long term investments. AMGP’s share of Antero Midstream’s earnings as a result of AMGP’s ownership of the IDRs is accounted for using the equity method of accounting. AMGP recognizes distributions earned from Antero Midstream as “Equity in earnings of Antero Midstream Partners LP” on its statement of operations in the period in which they are earned and are allocated to AMGP’s capital account. AMGP’s long-term interest in the IDRs on the balance sheet is recorded in “Investment in Antero Midstream Partners LP.” The ownership of the general partner interests and IDRs do not provide AMGP with any claim to the assets of Antero Midstream other than the balance in its Antero Midstream capital account. Income related to the IDRs is recognized as earned and increases AMGP’s capital account and equity investment. When these distributions are paid to AMGP, they reduce its capital account and its equity investment in Antero Midstream. See Note 6—Distributions from Antero Midstream.
Use of Estimates	(d) The preparation of the consolidated financial statements and notes in conformity with GAAP requires that management formulate estimates and assumptions that affect income, expenses, assets, and liabilities. Changes in facts and circumstances or discovery of new information may result in revised estimates, and actual results could differ from those estimates.
General and Administrative Expenses	(f) General and administrative costs incurred during 2016 and pre-IPO in 2017 primarily relate to legal and other costs incurred in connection with AMGP’s IPO. Post-IPO general and administrative expense consists primarily of management fees paid to Antero Resources, and other legal and administrative expenses. Additionally, in connection with the formation of a conflicts committee of the board of directors of the Partnership’s general partner to consider potential transactions involving us in connection with Antero Resources’ and Antero Midstream’s efforts to explore, review, and evaluate potential measures related to its valuation, the conflicts committee retained an investment advisor and attorneys. Attorneys’ fees related to this matter are charged to expense as incurred. For the year ended December 31, 2018, the AMGP has expensed $6.9 million related to conflicts committee expenses.
Equity-Based Compensation	(g) AMGP recognizes compensation cost related to all equity-based awards in the financial statements based on their estimated grant date fair value. AMGP has authorized and outstanding Series B Units and AMGP is authorized to grant common share awards. The grant date fair values are determined based on the type of award and may utilize market prices on the date of grant or a Monte Carlo simulation, as appropriate for the type of equity-based award. Compensation cost is recognized ratably over the applicable vesting or service period. Forfeitures are accounted for as they occur by reversing the expense previously recognized for awards that were forfeited during the period. See Note 5—Long-Term Incentive Plans for additional information regarding our equity-based compensation.
Fair Value Measures	(h ) Measures The Financial Accounting Standards Board (the “FASB”) Accounting Standards Codification Topic 820, Fair Value Measurements and Disclosures , clarifies the definition of fair value, establishes a framework for measuring fair value, and expands disclosures about fair value measurements. This guidance also relates to all nonfinancial assets and liabilities that are not recognized or disclosed on a recurring basis (e.g., the initial recognition of asset retirement obligations and impairments of long‑lived assets). The fair value is the price that AMGP estimates would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. A fair value hierarchy is used to prioritize inputs to valuation techniques used to estimate fair value. An asset or liability subject to the fair value requirements is categorized within the hierarchy based on the lowest level of input that is significant to the fair value measurement. AMGP’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability. The highest priority (Level 1) is given to unadjusted quoted market prices in active markets for identical assets or liabilities, and the lowest priority (Level 3) is given to unobservable inputs. Level 2 inputs are data, other than quoted prices included within Level 1, which are observable for the asset or liability, either directly or indirectly.
Net Income per Common Share	(i) Net Income per Common Share Net income per common share–basic for each period is computed by dividing n et income attributable to common shareholders by the basic weighted average number of common shares outstanding during the period. Net income per common share – diluted for each period is computed after giving consideration to the potential dilution from outstanding Series B units, calculated using the if converted method. During the periods in which AMGP incurs a net loss, diluted weighted average shares outstanding are equal to basic weighted average common shares outstanding because the effect of all equity awards is anti-dilutive. At December 31, 2017 and 2018, there were 4,777,759 and 1,365,525 shares, respectively, to be issued upon assumed conversion of the Series B Units. The effect of these awards is anti-dilutive for 2017 and 2018, and thus, AMGP’s diluted net income per common share for the years ended December 31, 2017 and 2018 is equal to our basic net income per common share.
Recently Issued Accounting Standards	(j) On June 20, 2018, the FASB issued Accounting Standards Update (“ASU”) No. 2018-07, Improvements to Nonemployee Share-Based Payment Accounting , which aligns the accounting for employee and nonemployee share-based payments. AMGP elected to adopt the standard as of October 1, 2018. As a result of adopting this standard, AMGP reclassified its $3.0 million liability for equity-based compensation to partners’ capital as of as of October 1, 2018. See Note 5—Long-Term Incentive Plans.

Income Tax (Tables)

Income Tax (Tables)	12 Months Ended
	Dec. 31, 2018
Income Taxes
Summary of income tax expense	Year Ended December 31, (in thousands) 2016 2017 2018 Current income tax expense $ 6,787 26,261 33,615 Deferred income tax benefit (368) — (1,304) Total income tax expense $ 6,419 26,261 32,311
Summary of reconciliation of income tax expense	Year Ended December 31, (in thousands) 2016 2017 2018 Federal income tax expense $ 5,646 10,005 20,773 State income tax expense, net of federal benefit 479 952 4,133 Non-deductible equity-based compensation — 13,296 8,087 Non-deductible IPO expenses 309 1,948 1 Other (15) 60 (683) Provision for income taxes $ 6,419 26,261 32,311

Distributions from Antero Mid_2

Distributions from Antero Midstream (Tables)	12 Months Ended
	Dec. 31, 2018
Distributions from Antero Midstream
Summary of percentage allocations for distributions	Marginal Percentage Interest in Distributions Total Quarterly Distribution Antero Midstream Common Unitholders Holder of IDRs above $0.1955 up to $0.2125 85 % 15 % above $0.2125 up to $0.2550 75 % 25 % above $0.2550 50 % 50 %
Summary of quarterly cash distribution to partners	Quarter Distribution Date Antero Midstream Distribution Amount Income Attributable to IDRs Q1 2016 May 25, 2016 $ $ 1,850 Q2 2016 August 24, 2016 $ $ 2,731 Q3 2016 November 24, 2016 $ $ 4,820 Q4 2016 February 8, 2017 $ $ 7,543 Q1 2017 May 10, 2017 $ $ 11,553 Q2 2017 August 16, 2017 $ $ 15,328 Q3 2017 November 16, 2017 $ $ 19,067 Q4 2017 February 13, 2018 $ $ 23,772 Q1 2018 May 18, 2018 $ $ 28,460 Q2 2018 August 17, 2018 $ $ 33,138 Q3 2018 November 16, 2018 $ $ 37,816

Cash Distributions (Tables)

Cash Distributions (Tables)	12 Months Ended
	Dec. 31, 2018
Cash Distributions
Schedule of quarterly distributions AMGP paid	The following table details the amount of quarterly distributions AMGP paid with respect to the quarter indicated (in thousands, except per share data): Distributions Quarter Record Date Distribution Date Common shareholders Antero Resources Investment Total Distributions per common share * May 9, 2017 September 13, 2017 $ — 15,908 15,908 * Q2 2017 August 3, 2017 August 23, 2017 5,026 — 5,026 $ Q3 2017 November 1, 2017 November 23, 2017 10,985 — 10,985 $ Total 2017 $ 16,011 15,908 31,919 Q4 2017 February 1, 2018 February 20, 2018 $ 13,964 — 13,964 $ Q1 2018 May 3, 2018 May 23, 2018 20,109 — 20,109 $ Q2 2018 August 2, 2018 August 22, 2018 23,276 — 23,276 $ Q3 2018 November 2, 2018 November 21, 2018 26, 817 — 26,817 $ Total 2018 $ 84,166 — 84,166 * Income relating to periods prior to May 9, 2017, the closing of our IPO, was distributed to Antero Investment prior to its liquidation.

Summarized Financial Informat_2

Summarized Financial Information for Antero Midstream (Tables)	12 Months Ended
	Dec. 31, 2018
Antero Midstream
Schedule of summarized income statement and balance sheet information for Antero Midstream	Summarized Antero Midstream Income Statement Information Year Ended December 31, 2016 2017 2018 Revenues $ 590,211 772,497 1,028,522 Operating expenses 332,100 447,819 420,952 Operating income 258,111 324,678 607,570 Net income and comprehensive income 236,703 307,315 585,944 Net income attributable to incentive distribution rights (16,944) (69,720) (142,906) Limited partners' interest in net income $ 219,759 237,595 443,038 Summarized Antero Midstream Balance Sheet Information December 31, 2017 2018 Current assets $ 120,385 138,435 Non-current assets 2,921,824 3,407,982 Current liabilities 121,316 99,686 Non-current liabilities 1,404,424 1,755,223 Partners' capital $ 1,516,469 1,691,508

Business and Organization (Deta

Business and Organization (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Antero Midstream Partners GP LLC
Business and Organization
Capital interest (as a percent)	100.00%
IDR LLC
Business and Organization
Percentage of amount of quarterly distribution in excess of threshold limit	6.00%
Threshold limit for quarterly distribution	$ 7.5
Antero Resources
Business and Organization
General and administrative fee	$ 0.5
Stonewall Gas Gathering LLC
Business and Organization
Ownership percentage	15.00%
Mark West Energy Partners, L. P.
Business and Organization
Capital interest (as a percent)	50.00%

Business and Organization - Sim

Business and Organization - Simplification (Details) - Simplification Agreement - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2019	Oct. 31, 2018	Oct. 30, 2018
Antero Resources | Forecast
Business and Organization
Cash without interest	$ 3
Number of new shares issued	1.6023
AM Public Unitholders | Forecast
Business and Organization
Cash without interest	$ 3.415
Number of new shares issued	1.6350
Threshold days	20 days
New AM | Forecast
Business and Organization
New AM's Common stock in exchange of Series B units	17,350,000
Aggregate cash consideration to be paid	$ 598
Antero Midstream | Revolving credit facility
Business and Organization
Maximum borrowing capacity		$ 2,000	$ 1,500

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	Oct. 01, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Significant Accounting Policies
Partners' capital		$ 30,861	$ 15,608	$ 10,269	$ 558
Income taxes
Statutory U.S. Federal tax rate (as a percent)		21.00%	35.00%	35.00%
General and Administrative Expenses
Attorneys’ fees		$ 6,900
Net Income (Loss) per Common Share
Antidilutive securities excluded from computation of earnings per share		1,365,525	4,777,759
Antero Midstream
Significant Accounting Policies
Partners' capital		$ 0
Consideration paid		0
Cost basis of interests		$ 0
Antero Resources | Antero Midstream
Significant Accounting Policies
Ownership percentage		52.80%
Series B Unit Awards classified as equity | ASU 2018-07
Recently Adopted Accounting Standard
Effect of adoption	$ 3,000
Series B Unit Awards classified as liability | ASU 2018-07
Recently Adopted Accounting Standard
Effect of adoption	$ (3,000)

Credit Facility (Details)

Credit Facility (Details) - Credit Facility - USD ($) $ in Millions	May 09, 2018	Dec. 31, 2018
Long-Term debt
Maximum amount of the Credit Facility	$ 12
Borrowings outstanding		$ 0
Base Rate
Long-Term debt
Margin rate added to base rate (as a percent)	1.00%
Federal Funds Rate
Long-Term debt
Margin rate added to base rate (as a percent)	0.50%
Eurodollar
Long-Term debt
Margin rate added to base rate (as a percent)	1.00%

Income Taxes - Income tax expen

Income Taxes - Income tax expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income tax expense
Current income tax expense	$ 33,615	$ 26,261	$ 6,787
Deferred income taxes	(1,304)		(368)
Total income tax expense	$ 32,311	$ 26,261	$ 6,419

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of income tax expense (benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Effective Income Tax Rate Reconciliation, Amount
Statutory U.S. Federal tax rate (as a percent)	21.00%	35.00%	35.00%
Federal income tax expense	$ 20,773	$ 10,005	$ 5,646
State income tax expense, net of federal benefit	4,133	952	479
Non-deductible equity-based compensation	8,087	13,296
Non-deductible IPO expenses	1	1,948	309
Other	(683)	60	(15)
Total income tax expense	32,311	$ 26,261	$ 6,419
Deferred tax asset	$ 1,304

Long-Term Incentive Plan (Detai

Long-Term Incentive Plan (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2018	Oct. 01, 2018	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Apr. 17, 2017
Aggregate disclosure
Units vested	65,745			65,745	32,875
Series B unit awards
Assumptions:
Units vested	65,745
Aggregate disclosure
Expense recognized				$ 34.4	$ 34.7
Series B Unit Awards classified as equity | ASU 2018-07
Long-Term Incentive Plan
Effect of adoption		$ 3
Series B Unit Awards classified as liability | ASU 2018-07
Long-Term Incentive Plan
Effect of adoption		$ (3)
2017 AMGP LTIP
Aggregate disclosure
Expense recognized				$ 0.7	$ 0.2
Number of common shares may be delivered pursuant to awards, subject to customary adjustments						930,851
Awards granted				49,225	11,762
Remaining shares granted	881,626			881,626
IDR LLC
Long-Term Incentive Plan
Percentage of amount of quarterly distribution in excess of threshold limit				6.00%
Threshold limit for quarterly distribution				$ 7.5
IDR LLC | Series B unit awards
Long-Term Incentive Plan
Authorized units	98,600			98,600
Outstanding units	98,600			98,600
Threshold limit for conversion of units to common shares	$ 2,000			$ 2,000
Assumptions:
Vesting period				3 years
Aggregate disclosure
Unamortized compensation expense related to nonvested Series B units	34.4			$ 34.4
IDR LLC | Series B unit awards | Maximum
Long-Term Incentive Plan
Percentage of amount of quarterly distribution in excess of threshold limit				6.00%
Percentage of amount of equity value in excess of threshold limit for conversion of units to common shares				6.00%
Percentage of newly issued common shares to the total number of issued and outstanding common shares allowed				6.00%
IDR LLC | Series B Unit Awards classified as equity
Assumptions:
Floor equity value	$ 2,000			$ 2,000
Expected volatility (as a percent)				43.00%
Risk free rate (as a percent)				2.45%
Weighted average cost of capital (as a percent)				7.25%
Estimated value (in dollars per unit)				$ 999
Aggregate disclosure
Awards forfeited				0	1,400
IDR LLC | Series B Unit Awards classified as liability
Assumptions:
Floor equity value			$ 3,300
Expected volatility (as a percent)			38.00%
Risk free rate (as a percent)			3.00%
Weighted average cost of capital (as a percent)			7.25%
Estimated value (in dollars per unit)			$ 1,673

Distributions from Antero Mid_3

Distributions from Antero Midstream (Details) $ / shares in Units, $ in Thousands	Nov. 21, 2018$ / shares	Aug. 22, 2018$ / shares	May 23, 2018$ / shares	Feb. 20, 2018$ / shares	Nov. 23, 2017$ / shares	Aug. 23, 2017$ / shares	Dec. 31, 2018USD ($)$ / shares	Sep. 30, 2018USD ($)$ / shares	Jun. 30, 2018USD ($)$ / shares	Mar. 31, 2018USD ($)$ / shares	Dec. 31, 2017USD ($)$ / shares	Sep. 30, 2017USD ($)$ / shares	Jun. 30, 2017USD ($)$ / shares	Mar. 31, 2017USD ($)$ / shares	Dec. 31, 2016USD ($)$ / shares	Sep. 30, 2016USD ($)$ / shares	Jun. 30, 2016USD ($)$ / shares	Mar. 31, 2016USD ($)$ / shares	Dec. 31, 2018$ / shares$ / item
Partnership equity and distributions
Cash distribution paid	$ 0.144	$ 0.125	$ 0.108	$ 0.075	$ 0.059	$ 0.027	$ 0.164
General Partner
Partnership equity and distributions
Total Distribution | $							$ 43,500	$ 37,816	$ 33,138	$ 28,460	$ 23,772	$ 19,067	$ 15,328	$ 11,553	$ 7,543	$ 4,820	$ 2,731	$ 1,850
Common units
Partnership equity and distributions
Cash distribution declared								$ 0.4400	$ 0.4150	$ 0.3900	$ 0.3650	$ 0.3400	$ 0.3200	$ 0.3000	$ 0.2800	$ 0.2650	$ 0.2500	$ 0.2350
Common Unit and Subordinated Unit
Partnership equity and distributions
Cash distribution declared							$ 0.47
Minimum | Above $0.1955 up to $0.2125
Partnership equity and distributions
Minimum cash distributions to trigger unitholder and general partner distributions																			$ 0.1955
Minimum | Above $0.2125 up to $0.2550
Partnership equity and distributions
Minimum cash distributions to trigger unitholder and general partner distributions																			0.2125
Minimum | Above $0.2550
Partnership equity and distributions
Minimum cash distributions to trigger unitholder and general partner distributions																			0.2550
Maximum | Above $0.1955 up to $0.2125
Partnership equity and distributions
Minimum cash distributions to trigger unitholder and general partner distributions																			0.2125
Maximum | Above $0.2125 up to $0.2550
Partnership equity and distributions
Minimum cash distributions to trigger unitholder and general partner distributions																			$ 0.2550
Antero Midstream
Partnership equity and distributions
Minimum quarterly cash distribution (per unit) | $ / item																			0.17
Annual cash distribution (per unit) | $ / item																			0.68
Minimum cash distributions to trigger unitholder and general partner distributions																			$ 0.1955
Antero Midstream | Above $0.1955 up to $0.2125
Partnership equity and distributions
Unitholders marginal percentage interest in distribution																			85.00%
General Partners marginal percentage interest in distribution																			15.00%
Antero Midstream | Above $0.2125 up to $0.2550
Partnership equity and distributions
Unitholders marginal percentage interest in distribution																			75.00%
General Partners marginal percentage interest in distribution																			25.00%
Antero Midstream | Above $0.2550
Partnership equity and distributions
Unitholders marginal percentage interest in distribution																			50.00%
General Partners marginal percentage interest in distribution																			50.00%

Cash Distributions (Details)

Cash Distributions (Details) - USD ($) $ / shares in Units, $ in Thousands	Nov. 21, 2018	Aug. 22, 2018	May 23, 2018	Feb. 20, 2018	Nov. 23, 2017	Sep. 13, 2017	Aug. 23, 2017	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Quarterly distribution paid
Distributions	$ 26,817	$ 23,276	$ 20,109	$ 13,964	$ 10,985	$ 15,908	$ 5,026		$ 84,166	$ 31,919
Distributions per common share	$ 0.144	$ 0.125	$ 0.108	$ 0.075	$ 0.059		$ 0.027	$ 0.164
Common shareholders
Quarterly distribution paid
Distributions	$ 26,817	$ 23,276	$ 20,109	$ 13,964	$ 10,985		$ 5,026		$ 84,166	16,011
Antero Resources Investment
Quarterly distribution paid
Distributions						$ 15,908				$ 15,908

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Allocation of costs
Payable to related party	$ 731	$ 57
Antero Resources
Allocation of costs
Payable to related party	$ 800
Antero Resources | Maximum
Allocation of costs
Payable to related party		$ 100

Quarterly Financial Informati_2

Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information (Unaudited)
Total income	$ 43,492	$ 37,816	$ 33,145	$ 28,453	$ 23,772	$ 19,067	$ 15,328	$ 11,553	$ 142,906	$ 69,720	$ 16,944
Total expenses	11,979	10,803	11,509	9,560	8,941	8,932	12,834	10,427	43,851	41,134	814
Net income and comprehensive income	21,388	18,028	14,387	12,805	5,907	2,978	(3,261)	$ (3,299)	66,608	2,325	$ 9,711
Net income attributable to Antero Midstream GP LP subsequent to IPO					5,907	2,978	(1,621)
Net income attributable to vested Series B units	(3,719)	(598)	(506)	(413)	(784)				(5,236)	(784)
Net income attributable to common shareholders	$ 17,669	$ 17,430	$ 13,881	$ 12,392	$ 5,123	$ 2,978	$ (1,621)		$ 61,372	$ 6,480
Net income per common share - basic and diluted	$ 0.10	$ 0.09	$ 0.07	$ 0.07	$ 0.03	$ 0.02	$ (0.01)		$ 0.33	$ 0.03

Summarized Financial Informat_3

Summarized Financial Information for Antero Midstream (Details) - Antero Midstream - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Summarized Income Statement Information
Revenues	$ 1,028,522	$ 772,497	$ 590,211
Operating expenses	420,952	447,819	332,100
Operating income	607,570	324,678	258,111
Net income and comprehensive income	585,944	307,315	236,703
Net income attributable to incentive distribution rights	(142,906)	(69,720)	(16,944)
Limited partners' interest in net income	443,038	237,595	$ 219,759
Summarized Balance Sheet Information
Current assets	138,435	120,385
Non-current assets	3,407,982	2,921,824
Current liabilities	99,686	121,316
Non-current liabilities	1,755,223	1,404,424
Partners' capital	$ 1,691,508	$ 1,516,469