Acquisition - Summary of Acquired Non-Impaired Loans as of Acquisition Date (Details) - Oak Park River Forest Bankshares, Inc. $ in Thousands	Apr. 30, 2019 USD ($)
Business Acquisition [Line Items]
Fair value	$ 204,496
Gross contractual amounts receivable	254,755
Estimate of contractual cash flows not expected to be collected	12,987	[1]
Estimate of contractual cash flows expected to be collected	$ 241,768

[1] Includes interest payments not expected to be collected due to loan prepayments as well as principal and interest payments not expected to be collected due to customer default.