Equity Based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		7 Months Ended	9 Months Ended		12 Months Ended
	Mar. 12, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Additional disclosures
Expense recognized		$ 20,129		$ 3,600	$ 53,095
Unamortized expense		18,000		18,000	18,000
Reversal of recognized expense					200
Common Stock
Additional disclosures
Shares exchanged	5,782,601
Antero Resources
Additional disclosures
Unamortized expense		32,000		32,000	32,000
Midstream LTIP
Additional disclosures
Unamortized expense		$ 15,000		$ 15,000	$ 15,000
Weighted average period for recognizing unrecognized stock-based compensation expense					2 years 7 months 6 days
Restricted unit and phantom unit awards
Number of units
AMP LTIP Awards converted into AMC LTIP Awards					1,068,900
Granted (in shares)					683,807
Vested (in shares)					(400,439)
Forfeited (in shares)					(72,110)
Total awarded and unvested at the end of the period (in shares)		1,280,158		1,280,158	1,280,158
Weighted average grant date fair value
AMP LTIP Awards converted into AMC LTIP Awards (in dollars per unit)		$ 14.58		$ 14.58	$ 14.58
Granted (in dollars per unit)					14.03
Vested (in dollars per unit)					14.18
Forfeited (in dollars per unit)					14.43
Total awarded and unvested at the end of the period (in dollars per unit)		$ 14.41		$ 14.41	$ 14.41
Aggregate intrinsic value
Total awarded and unvested at the end of the period		$ 9,473		$ 9,473	$ 9,473
Series B unit awards
Additional disclosures
Units vested							65,745
2017 AMGP LTIP
Additional disclosures
Expense recognized		0	$ 200		200	$ 500
Shares exchange ratio	1.8926
Awards issued	0
Awards outstanding	0
AMC LTIP
Additional disclosures
Expense recognized		$ 1,400			$ 2,800
Number of stock-based compensation awards authorized	15,398,901
Shares exchange ratio	1.8926
Number of shares available for future grant under the Plan		13,673,136		13,673,136	13,673,136
Series B Unit, Vested and Unvested
Additional disclosures
Shares exchange ratio	176.0041
Exchanged B Units
Additional disclosures
Expense recognized		$ 18,000			$ 47,000
Shares exchanged	17,353,999
Common stock issued in exchange	98,600
Unvested Series B Units
Number of units
AMP LTIP Awards converted into AMC LTIP Awards	32,855
Additional disclosures
Expense recognized		$ 8,000			$ 26,000
ROIC PSUs
Number of units
Granted (in shares)					164,196
Forfeited (in shares)					(15,890)
Total awarded and unvested at the end of the period (in shares)		148,306		148,306	148,306
Weighted average grant date fair value
Granted (in dollars per unit)					$ 14.16
Forfeited (in dollars per unit)					14.16
Total awarded and unvested at the end of the period (in dollars per unit)		$ 14.16		$ 14.16	$ 14.16
Additional disclosures
Unamortized expense		$ 2,100		$ 2,100	$ 2,100
Vesting period					3 years
ROIC PSUs | Minimum
Additional disclosures
Number of shares of common stock that may be earned ultimately.					0.00%
ROIC PSUs | Maximum
Additional disclosures
Number of shares of common stock that may be earned ultimately.					200.00%
IDR LLC
Additional disclosures
Percentage of amount of quarterly distribution in excess of threshold limit							6.00%
Threshold limit for quarterly distribution							$ 7,500
IDR LLC | Series B unit awards
Additional disclosures
Authorized units							98,600
Outstanding units							98,600
Threshold limit for conversion of units to common shares							$ 2,000,000
IDR LLC | Series B unit awards | Maximum
Additional disclosures
Percentage of amount of equity value in excess of threshold limit for conversion of units to common shares							6.00%
IDR LLC | Series B Unit Awards classified as equity
Additional disclosures
Floor equity value	$ 2,000,000
Expected volatility (as a percent)	40.00%
Risk free rate (as a percent)	2.51%
Weighted average cost of capital (as a percent)	7.25%
Estimated value (in dollars per unit)	$ 1,257