Net Income (Loss) Per Share Attributable to Class A Common Stock (Details) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended		6 Months Ended
	May 21, 2026	Jun. 30, 2026 USD ($) $ / shares shares	Jun. 30, 2026 USD ($) $ / shares shares	Jun. 30, 2025 USD ($)	Jun. 30, 2026 USD ($) $ / shares shares	Jun. 30, 2025 USD ($)
Numerator: ($ in thousands)
Net income (loss) attributable to Lincoln International Inc. | $		$ 455	$ 455	$ 33,837	$ 455	$ 58,427
Net income impact due to:
Exchange of LILP common units to Class A common stock | $		0
Net income (loss) attributable to Lincoln International, Inc. - Diluted | $		$ 455
Denominator:
Common stock , issued (in shares)		102,191,562	102,191,562		102,191,562
Common stock, outstanding (in shares)		102,191,562	102,191,562		102,191,562
Common unit to common stock conversion ratio	1
Class A
Denominator:
Common stock , issued (in shares)		34,846,972	34,846,972		34,846,972
Common stock, outstanding (in shares)		34,846,972	34,846,972		34,846,972
IPO Liquidity shares (in shares)		1,433,927
Weighted average shares of Class A common stock - Basic (in shares)		36,280,899	36,280,899		36,280,899
Exchangeable LILP common units (in shares)		0
Weighted average shares of Class A common stock – Diluted (in shares)		40,017,177	40,017,177		40,017,177
Earnings per share of Class A common stock - Basic (usd per share) | $ / shares		$ 0.01	$ 0.01		$ 0.01
Earnings per share of Class A common stock - Diluted (usd per share) | $ / shares		$ 0.01	$ 0.01		$ 0.01
IPO Equity Awards (RSUs)
Net income impact due to:
Options | $		$ 0
Denominator:
Vesting period	4 years
IPO Equity Awards (RSUs) | Class A
Denominator:
IPO Equity Awards (RSUs)/Options (in shares)		620,312
IPO Equity Awards (RSUs) | Minimum
Denominator:
Vesting period		3 years
IPO Equity Awards (RSUs) | Maximum
Denominator:
Vesting period		4 years
Option
Net income impact due to:
Options | $		$ 0
Option | Class A
Denominator:
IPO Equity Awards (RSUs)/Options (in shares)		3,115,966