Net Income (Loss) Per Common Share - Reconciliation of Net Income (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Net income (loss) attributable to Earthstone Energy, Inc.	$ 10,418	$ (5,445)	$ (4,286)	$ (5,076)
Net income (loss) per common share attributable to Earthstone Energy, Inc.:
Basic (in dollars per share)	$ 0.21	$ (0.18)	$ (0.09)	$ (0.17)
Diluted (in dollars per share)	$ 0.20	$ (0.18)	$ (0.09)	$ (0.17)
Weighted average common shares outstanding
Basic (in shares)	49,243,185	30,073,635	45,406,952	29,810,705
Add potentially dilutive securities:
Unvested restricted stock units (in shares)	525,475	0	0	0
Unvested performance units (in shares)	2,894,282	0	0	0
Diluted weighted average common shares outstanding (in shares)	52,662,942	30,073,635	45,406,952	29,810,705