Costs incurred to effect a business combination which have been expensed during the period. Such costs could include business integration costs, systems integration and conversion costs, and severance and other employee-related costs.

No definition available.

Name:	us-gaap_BusinessCombinationIntegrationRelatedCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Merger Related Expenses - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Jun. 30, 2020
Business Acquisition [Line Items]
Merger-related expenses		$ 219,000	$ 4,349,000	$ 219,000
MSB Financial Corporation [Member]
Business Acquisition [Line Items]
Merger-related expenses	$ 4,300,000				$ 951,000