Loans Receivable - Schedule Of Carrying Value Of Collateral Dependent Individually Analyzed Loans (Detail) - USD ($) $ in Thousands			6 Months Ended
		Jul. 10, 2020	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance		$ (3,901)
Individually Analyzed Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans			$ 58,658
Balance			724
Individually Analyzed Loans [Member] | One-to Four-Family Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans	[1]		6,598
Balance	[1]		206
Individually Analyzed Loans [Member] | Home Equity Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans	[1]		116
Individually Analyzed Loans [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans			51,944
Balance			518
Individually Analyzed Loans [Member] | Commercial Loan [Member] | Non-Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans	[2]		38,249
Balance	[2]		518
Individually Analyzed Loans [Member] | Commercial Loan [Member] | Commercial Business [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans	[3]		195
Individually Analyzed Loans [Member] | Multi-Family Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans			$ 13,500

[1] Secured by one- to four-family properties.

[2] Secured by income-producing property.

[3] Secured by business assets.