Acquisition of MSB Financial Corp. - Additional Information (Detail) - USD ($)		3 Months Ended	6 Months Ended
	Jul. 10, 2020	Dec. 31, 2020	Dec. 31, 2020
Business Acquisition [Line Items]
Bargain purchase gain			$ 3,053,000
MSB Financial Corporation [Member]
Business Acquisition [Line Items]
Closing date	Jul. 10, 2020
Cash paid for acquisition	$ 9,830,000
Issuance of shares of common stock to MSB stockholders in conjunction with merger	5,853,811
Bargain purchase gain	$ 3,053,000
Core deposit intangible	$ 690,000
Business combination provisional adjustments		$ 0
MSB Financial Corporation [Member] | Core Deposit [Member]
Business Acquisition [Line Items]
Intangible asset, estimated useful life			10 years