Net Income (Loss) Per Common Share - Reconciliation of Net Loss Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Net (loss) income attributable to Earthstone Energy, Inc.	$ (13,547)	$ 719
Net (loss) income per common share attributable to Earthstone Energy, Inc.:
Basic (in dollars per share)	$ (0.45)	$ 0.02
Diluted (in dollars per share)	$ (0.45)	$ 0.02
Weighted average common shares outstanding
Basic (in shares)	29,911,625	28,983,354
Add potentially dilutive securities:
Unvested restricted stock units (in shares)	0	0
Unvested performance units (in shares)	0	377,531
Diluted weighted average common shares outstanding (in shares)	29,911,625	29,360,885