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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Present value of lessee's discounted obligation for lease payments from finance lease.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Junior Subordinated Notes, which have a lower priority than senior instruments.

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The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a set, unchanging rate.

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Including the current and noncurrent portions, the carrying value as of the balance sheet date of notes payable to banks, excluding mortgage notes, initially due beyond one year or beyond the operating cycle if longer.

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The carrying amount as of the balance sheet date for the aggregate of other miscellaneous borrowings owed by the reporting entity.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of subordinated debt (with initial maturities beyond one year or beyond the operating cycle if longer). Subordinated debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets.

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The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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Carrying value as of the balance sheet date of uncollateralized debt obligation (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion.

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Other Borrowings - Summary of Other Borrowings (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Aug. 31, 2014
Debt Instrument [Line Items]
Lease liability	$ 16,621	$ 17,233
Other borrowings	597,207	296,670
Old National Bank
Debt Instrument [Line Items]
Other basis adjustments	2,526	2,839
Lease liability	16,621	17,233
Old National Bancorp
Debt Instrument [Line Items]
Other basis adjustments	$ 27,231	(3,044)
Senior Unsecured Notes \| Old National Bancorp
Debt Instrument [Line Items]
Fixed rate	4.125%		4.125%
Senior unsecured notes (fixed rate 4.125%) maturing August 2024	$ 175,000	175,000	$ 175,000
Unamortized debt issuance costs related to senior unsecured notes	(364)	(403)
Junior Subordinated Debentures \| Old National Bancorp
Debt Instrument [Line Items]
Junior subordinated debentures (variable rates of 1.84% to 6.95%) maturing July 2031 to September 2037	$ 136,643	42,000
Subordinated Debt
Debt Instrument [Line Items]
Fixed rate	5.875%
Subordinated debentures	$ 150,000	0
Subordinated Debt \| Old National Bank
Debt Instrument [Line Items]
Variable rate	4.66%
Subordinated debentures	$ 12,000	12,000
Notes Payable to Banks \| Old National Bank
Debt Instrument [Line Items]
Leveraged loans for NMTC (fixed rates of 1.00% to 1.43%) maturing December 2046 to December 2052	$ 77,550	$ 51,045
Minimum \| Junior Subordinated Debentures \| Old National Bancorp
Debt Instrument [Line Items]
Variable rate	1.84%
Minimum \| Notes Payable to Banks \| Old National Bank
Debt Instrument [Line Items]
Fixed rate	1.00%
Maximum \| Junior Subordinated Debentures \| Old National Bancorp
Debt Instrument [Line Items]
Variable rate	6.95%
Maximum \| Notes Payable to Banks \| Old National Bank
Debt Instrument [Line Items]
Fixed rate	1.43%