Equity-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2018

Equity-Based Compensation

Schedule of equity-based compensation expense

The Company’s equity‑based compensation expense, by type of award, was as follows for the years ended December 31, 2016, 2017, and 2018 (in thousands):

	Year Ended December 31,
	2016		2017		2018
Restricted stock unit awards	$	73,081		70,866		41,505
Stock options		2,578		2,375		1,799
Performance share unit awards		8,685		10,797		9,659
Antero Midstream phantom unit awards		16,095		17,461		15,351
Equity awards issued to directors		1,982		1,946		2,100
Total expense	$	102,421		103,445		70,414

Summary of restricted stock and restricted stock unit awards activity

		Weighted average		Aggregate
	Number of shares	grant date fair value		intrinsic value (in thousands)
Total awarded and unvested—December 31, 2017	3,424,084	$	28.51	$	65,058
Granted	687,626	$	20.69
Vested	(1,933,130)	$	29.90
Forfeited	(466,095)	$	25.65
Total awarded and unvested—December 31, 2018	1,712,485	$	24.57	$	16,080

Summary of stock option activity

				Weighted
		Weighted average		average remaining	Intrinsic
	Stock options	exercise price		contractual life	value (in thousands)
Outstanding at December 31, 2017	660,512	$	50.48	7.06	$	—
Granted	—	$	—
Exercised	—	$	—
Forfeited	(80,895)	$	50.00
Expired	—	$	—
Outstanding at December 31, 2018	579,617	$	50.55	5.81	$	—
Vested or expected to vest as of  December 31, 2018	579,617	$	50.55	5.81	$	—
Exercisable at December 31, 2018	462,217	$	50.69	5.69	$	—

Summary of Performance Stock Unit activity

A summary of PSU activity for the year ended December 31, 2018 is as follows:

	Number of units	Weighted average grant date fair value
Total awarded and unvested—December 31, 2017	1,283,843	$	28.29
Granted	756,466	$	23.61
Vested	(41,666)	$	27.38
Forfeited	(231,344)	$	27.89
Total awarded and unvested—December 31, 2018	1,767,299	$	26.36

Schedule of weighted average fair value assumptions used for PSUs granted

	Year Ended December 31,
	2017			2018
Dividend yield		—	%		—	%
Volatility		42	%		41	%
Risk-free interest rate		1.40	%		2.49	%
Weighted average fair value of awards granted	$	26.21		$	24.85

Schedule of outstanding unvested restricted stock awards vesting schedule

	Number of units	Weighted average grant date fair value		Aggregate intrinsic value (in thousands)
Total awarded and unvested—December 31, 2017	1,042,963	$	28.69	$	30,288
Granted	260,847	$	25.84
Vested	(577,566)	$	28.63
Forfeited	(143,244)	$	28.08
Total awarded and unvested—December 31, 2018	583,000	$	27.63	$	12,470