Document And Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Amendment Flag	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Registrant Name	RILEY EXPLORATION PERMIAN, INC.
Entity Central Index Key	0001001614
Entity File Number	1-15555
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	87-0267438
Entity Address, Address Line One	29 E. Reno Avenue
Entity Address, Address Line Two	Suite 500
Entity Address, City or Town	Oklahoma City
Entity Address, State or Province	OK
Entity Address, Postal Zip Code	73104
City Area Code	405
Local Phone Number	415-8677
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Voluntary Filers	No
Entity Public Float		$ 2.9
Current Fiscal Year End Date	--12-31
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Trading Symbol	REPX
Title of 12(b) Security	Common Stock
Security Exchange Name	NYSE
Entity Common Stock, Shares Outstanding	890,420
ICFR Auditor Attestation Flag	false