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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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Amount of cash inflow from exercise of option under share-based payment arrangement.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Gross number of share options (or share units) granted during the period.

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Number of options outstanding, including both vested and non-vested options.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of options vested.

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Total number of shares issued during the period, including shares forfeited, as a result of Restricted Stock Awards.

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Share-Based Compensation - Additional Information (Details) - USD ($)					1 Months Ended		12 Months Ended
	May 15, 2019	Apr. 30, 2019	Oct. 03, 2017	Jul. 06, 2017	Feb. 29, 2020	Oct. 31, 2014	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jun. 30, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, voting par value							$ 0.01	$ 0.01
Proceeds from the exercise of stock options							$ 3,146,000	$ 2,340,000
Oak Park River Forest Bankshares, Inc.
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Consideration paid in cash	$ 4,200,000	$ 6,163,000
Business combination conversion of outstanding options	35,870
Performance-based Restricted Shares \| Subsequent Event
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of restricted voting common stock granted					31,928
Period for number of shares earned under return on average assets					3 years
Performance Options Grants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options vested			414,894
Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock in connection with restricted stock awards, shares							180,664	129,057	70,398
Number of options exercised							241,211	205,152
Common Stock \| Restricted Shares \| Subsequent Event
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of restricted voting common stock granted					172,660
Common stock, voting par value					$ 0.01
Common Stock \| Restricted Shares \| Each Anniversary of Grant Date Over Four Years \| Subsequent Event
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period					4 years
Shares vest on grant date					101,946
Common Stock \| Restricted Shares \| Each Anniversary of Grant Date Vest Over Three Years \| Subsequent Event
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period					3 years
Shares vest on grant date					38,786
Omnibus Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock reserved for issuance												1,550,000
Number of common shares available for future grants							1,169,881
Omnibus Plan \| Restricted Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period									4 years
Shares of restricted voting common stock granted							210,622
Restricted shares vested							48,491	2,975	0
Fair value of restricted shares, vested							$ 900,000	$ 62,000
Restricted shares vested							48,491	2,975	0
Fair value of unvested restricted stock awards							$ 6,400,000
Number of shares outstanding							328,653	196,480
Omnibus Plan \| Performance-based Restricted Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of restricted voting common stock granted							20,975	11,165
Period for number of shares earned under return on average assets							3 years	3 years
Minimum target percentage in assets of peer group consisting publicly-traded bank holding companies								50.00%
Maximum target percentage in assets of peer group consisting publicly-traded bank holding companies								200.00%
Omnibus Plan \| Performance-based Restricted Shares \| Threshold performance
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of target number of shares to be earned								25.00%
Omnibus Plan \| Performance-based Restricted Shares \| 50th Percentile Performance
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of target number of shares to be earned								100.00%
Omnibus Plan \| Performance-based Restricted Shares \| 75th Percentile Performance
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of target number of shares to be earned								125.00%
Omnibus Plan \| Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock in connection with restricted stock awards, shares				58,900					11,898
Omnibus Plan \| Common Stock \| Restricted Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of restricted voting common stock granted							189,647	131,157
Common stock, voting par value							$ 0.01	$ 0.01
Shares vested							4,571
Omnibus Plan \| Common Stock \| Restricted Shares \| Each Anniversary of Grant Date Over Four Years
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period							4 years	4 years
Shares vest on grant date							111,823	102,559
Omnibus Plan \| Common Stock \| Restricted Shares \| Each Anniversary of Grant Date Vest Over Three Years
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period							3 years	3 years
Shares vest on grant date							72,570	15,165
Omnibus Plan \| Common Stock \| Restricted Shares \| First Anniversary of Grant Date
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares vest on grant date							683	2,268
MBG Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of options granted									0
Number of options exercised									0
BYB Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common shares available for future grants												0
Number of options granted									0	212,400	1,634,568
Number of options exercised							127,997	148,748	0
Number of shares outstanding							1,410,075	1,598,872
Options vested							17,500
Proceeds from the exercise of stock options							$ 1,900,000	$ 1,700,000
Tax benefit from exercise of stock options							$ 145,000	$ 449,000
BYB Plan \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common shares available for future grants						2,476,122
BYB Plan \| Time Options Grants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award contractual term						10 years
BYB Plan \| Time Options Grants \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period						5 years
BYB Plan \| Time Options Grants \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period						1 year
BYB Plan \| Performance Options Grants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award contractual term						10 years
BYB Plan \| Performance Options Grants \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period						5 years
BYB Plan \| Performance Options Grants \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period						1 year
FEB Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of options exercised							113,214	56,404
Number of shares outstanding							511,169	624,383
Proceeds from the exercise of stock options							$ 1.3	$ 601,000
Tax benefit from exercise of stock options							$ 253,000	$ 168,000
Conversion calculation percentage							472.50%
FEB Plan \| Restricted Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares outstanding							0