Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Financial assets:
Cash and due from banks	$ 56,632	$ 38,565
Interest earning deposits with financial institutions	58,545	713,542
Securities available-for-sale	1,539,359	1,693,632
FHLBC and FRBC Stock	20,530	13,257
Mortgage servicing rights	11,189	7,097
Financial liabilities:
Noninterest bearing deposits	2,051,702	2,087,649
Other short-term borrowings	90,000
Junior subordinated debentures	25,773	25,773
Senior notes	44,585	44,480
Reported Value Measurement
Financial assets:
Cash and due from banks	56,632	38,565
Interest earning deposits with financial institutions	58,545	713,542
Securities available-for-sale	1,539,359	1,693,632
FHLBC and FRBC Stock	20,530	13,257
Loans held for sale	491	4,737
Net loans	3,820,129	3,376,523
Mortgage servicing rights	11,189	7,097
Interest rate swap agreements	6,391	3,494
Interest rate lock commitments and forward contracts	76	508
Interest receivable on securities and loans	22,661	13,431
Financial liabilities:
Noninterest bearing deposits	2,051,702	2,087,649
Interest bearing deposits	3,059,021	3,378,583
Securities sold under repurchase agreements	32,156	50,337
Other short-term borrowings	90,000
Junior subordinated debentures	25,773	25,773
Subordinated debentures	59,297	59,212
Senior notes	44,585	44,480
Note payable and other borrowings	9,000	19,074
Interest rate swap agreements	12,264	6,788
Interest payable on deposits and borrowings	1,657	1,706
Estimate of Fair Value Measurement
Financial assets:
Cash and due from banks	56,632	38,565
Interest earning deposits with financial institutions	58,545	713,542
Securities available-for-sale	1,539,359	1,693,632
FHLBC and FRBC Stock	20,530	13,257
Loans held for sale	491	4,737
Net loans	3,681,387	3,407,596
Mortgage servicing rights	11,189	7,097
Interest rate swap agreements	6,391	3,494
Interest rate lock commitments and forward contracts	76	508
Interest receivable on securities and loans	22,661	13,431
Financial liabilities:
Noninterest bearing deposits	2,051,702	2,087,649
Interest bearing deposits	3,042,740	3,375,930
Securities sold under repurchase agreements	32,156	50,337
Other short-term borrowings	90,000
Junior subordinated debentures	21,907	18,557
Subordinated debentures	52,322	60,111
Senior notes	44,248	44,480
Note payable and other borrowings	8,984	19,411
Interest rate swap agreements	12,264	6,788
Interest payable on deposits and borrowings	1,657	1,706
Fair Value, Inputs, Level 1
Financial assets:
Cash and due from banks	56,632	38,565
Interest earning deposits with financial institutions	58,545	713,542
Securities available-for-sale	212,129	202,339
Financial liabilities:
Noninterest bearing deposits	2,051,702	2,087,649
Senior notes	44,248	44,480
Fair Value, Inputs, Level 2
Financial assets:
Securities available-for-sale	1,291,219	1,476,057
FHLBC and FRBC Stock	20,530	13,257
Loans held for sale	491	4,737
Interest rate swap agreements	6,391	3,494
Interest rate lock commitments and forward contracts	76	508
Interest receivable on securities and loans	22,661	13,431
Financial liabilities:
Interest bearing deposits	3,042,740	3,375,930
Securities sold under repurchase agreements	32,156	50,337
Other short-term borrowings	90,000
Junior subordinated debentures	21,907	18,557
Subordinated debentures	52,322	60,111
Note payable and other borrowings	8,984	19,411
Interest rate swap agreements	12,264	6,788
Interest payable on deposits and borrowings	1,657	1,706
Fair Value, Inputs, Level 3
Financial assets:
Securities available-for-sale	36,011	15,236
Net loans	3,681,387	3,407,596
Mortgage servicing rights	$ 11,189	$ 7,097