Loans and Allowance for Loan Losses - Association's Loan Portfolio Aging Analysis (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	$ 1,423	$ 2,226
Current	511,875	513,661
Total loans	513,298	515,887	$ 496,397
Total Loans 90 Days Past Due & Accruing	140	304
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	42	267
Current	152,406	144,846
Total loans	152,448	145,113	148,299
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	320	248
Current	101,208	107,333
Total loans	101,528	107,581	82,692
Total Loans 90 Days Past Due & Accruing	17
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	66	67
Current	8,199	7,462
Total loans	8,265	7,529	7,355
One- to four-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	972	1,644
Current	122,521	127,232
Total loans	123,493	128,876	127,679
Total Loans 90 Days Past Due & Accruing	123	304
Multi-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	105,836	96,195
Total loans	105,836	96,195	102,756
Home equity lines of credit [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	23
Current	7,835	8,551
Total loans	7,858	8,551	8,867
Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	13,870	22,042
Total loans	13,870	22,042	$ 18,749
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	993	1,230
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	42	172
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	303
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	26	24
Financing Receivables, 30 to 59 Days Past Due [Member] | One- to four-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	599	1,034
Financing Receivables, 30 to 59 Days Past Due [Member] | Home equity lines of credit [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	23
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	187	367
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due		95
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due		4
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	40	43
Financing Receivables, 60 to 89 Days Past Due [Member] | One- to four-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	147	225
Financing Receivables, 90 Days or Greater [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	243	629
Financing Receivables, 90 Days or Greater [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	17	244
Financing Receivables, 90 Days or Greater [Member] | One- to four-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	$ 226	$ 385