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Acquisition of a Business - Summary of Estimated Fair Values of Assets and Liabilities Assumed as of Acquisition Date (Parenthetical) (Details) - $ / shares	Apr. 30, 2019	May 31, 2018
Oak Park River Forest Bankshares, Inc.
Business Acquisition [Line Items]
Stock issued (in shares)	1,464,558
Stock issued (in dollars per share)	$ 20.02
First Evanston Bancorp, Inc.
Business Acquisition [Line Items]
Stock issued (in shares)		6,682,850
Stock issued (in dollars per share)		$ 21.62

X

- Definition

Number of shares of equity interests issued or issuable to acquire entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)(4)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

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- Definition

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.

+ References

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- Definition

Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

+ References

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