Cover Page - shares	9 Months Ended
	Sep. 30, 2021	Nov. 08, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity File Number	001-40829
Entity Registrant Name	Sterling Check Corp.
Entity Central Index Key	0001645070
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	37-1784336
Entity Address, Address Line One	1 State Street Plaza
Entity Address, Address Line Two	24th Floor
Entity Address, State or Province	NY
Entity Address, City or Town	New York
Entity Address, Postal Zip Code	10004
City Area Code	800
Local Phone Number	853-3228
Title of 12(b) Security	Common stock, $0.01 par value
Trading Symbol	STER
Security Exchange Name	NASDAQ
Entity Current Reporting Status	No
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		95,808,843