FHLB ADVANCES AND OTHER BORROWINGS - Summary of FHLB Advances (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
FHLB ADVANCES AND OTHER BORROWINGS
Total FHLB advances and other borrowings	$ 779,171	$ 493,311
Midland States Bancorp, Inc \| Series G Preferred Stock
FHLB ADVANCES AND OTHER BORROWINGS
Long term debt	$ 171	$ 181
Federal Home Loan Bank Advances, Interest Rate Information
Preferred stock, shares issued (in shares)	171	181
Preferred stock, par value (in USD per share)	$ 1,000	$ 1,000
Midland States Bank \| Fixed rate, fixed term maturing through May 2021
FHLB ADVANCES AND OTHER BORROWINGS
Total FHLB advances and other borrowings	$ 304,000	$ 28,130
Federal Home Loan Bank Advances, Interest Rate Information
FHLB advances interest rate	0.24%	2.56%
Midland States Bank \| Putable Fixed Rate Loan Maturing Through August 2021
FHLB ADVANCES AND OTHER BORROWINGS
Total FHLB advances and other borrowings	$ 475,000	$ 465,000
Federal Home Loan Bank Advances, Interest Rate Information
FHLB advances interest rate	2.01%	2.34%

Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages.

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States the interest rate applicable to Federal Home Loan Bank advances outstanding as of the Balance Sheet date.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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