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Acquisition - Carrying Value of Acquired Loans (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Book value of loans acquired	$ 1,550,180	$ 1,635,802
Accretion recorded on acquired loans year to date	2,416	966
West Suburban Bancorp, Inc
Business Acquisition [Line Items]
Book value of loans acquired	1,442,906	1,521,161
Abc Bank
Business Acquisition [Line Items]
Book value of loans acquired	62,438	68,783
Talmer Bank
Business Acquisition [Line Items]
Book value of loans acquired	44,836	45,858
PCI
Business Acquisition [Line Items]
Book value of loans acquired	93,135	106,956
Accretion recorded on acquired loans year to date	400	401
PCI | West Suburban Bancorp, Inc
Business Acquisition [Line Items]
Book value of loans acquired	88,601	102,409
PCI | Abc Bank
Business Acquisition [Line Items]
Book value of loans acquired	4,534	4,547
Non-PCI
Business Acquisition [Line Items]
Book value of loans acquired	1,457,045	1,528,846
Accretion recorded on acquired loans year to date	2,016	565
Non-PCI | West Suburban Bancorp, Inc
Business Acquisition [Line Items]
Book value of loans acquired	1,354,305	1,418,752
Non-PCI | Abc Bank
Business Acquisition [Line Items]
Book value of loans acquired	57,904	64,236
Non-PCI | Talmer Bank
Business Acquisition [Line Items]
Book value of loans acquired	$ 44,836	$ 45,858

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- Definition

Amount of increase (decrease) of the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 15
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=123409700&loc=d3e13503-111538

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=121614798&loc=d3e15032-111544

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The recorded balance, net of any applicable reductions (for example, unamortized accretable yield and allowance for loan losses). This relates to loans not accounted for debt securities with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
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