Cover - shares	9 Months Ended
	Sep. 30, 2026	Oct. 30, 2026
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2026
Document Transition Report	false
Entity File Number	001-43306
Registrant Name	Lincoln International, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	38-4224068
Entity Address, Address Line One	110 North Wacker Drive, 51st Floor
Entity Address, City or Town	Chicago
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60606
City Area Code	312
Local Phone Number	580-8339
Title of 12(b) Security	Class A common stock, par value $0.00001 per share
Trading Symbol	LCLN
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Shell Company	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q3
Amendment Flag	false
Document Fiscal Year Focus	2026
Entity Central Index Key	0001925283
Class A
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		36,372,399
Class B
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		28,596,847
Class C
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		38,866,382