PARTY-IN-INTEREST TRANSACTIONS (Details) - EBP 002 - USD ($)	Dec. 31, 2025	Dec. 31, 2024
EBP, Related Party and Party-in-Interest Transactions [Line Items]
Cash	$ 9,424	$ 21,855
Participant directed investments, at fair value	328,149,763	262,267,135
Notes receivable from participants	2,894,127	2,496,253
Cash \| Charles Schwab Bank
EBP, Related Party and Party-in-Interest Transactions [Line Items]
Cash	9,424	21,855
Money market account \| Charles Schwab Bank
EBP, Related Party and Party-in-Interest Transactions [Line Items]
Participant directed investments, at fair value	7,452,017	6,344,760
Common stock \| First Busey Corporation
EBP, Related Party and Party-in-Interest Transactions [Line Items]
Participant directed investments, at fair value	603,695	610,675
Stock fund \| First Busey Corporation
EBP, Related Party and Party-in-Interest Transactions [Line Items]
Participant directed investments, at fair value	9,510,730	8,813,046
Managed funds \| First Busey Corporation
EBP, Related Party and Party-in-Interest Transactions [Line Items]
Participant directed investments, at fair value	$ 83,054,745	$ 69,852,148

Amount of noninterest-bearing cash held by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

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