Loans and Allowance for Loan Losses - Association's Loan Portfolio Aging Analysis (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2018
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	$ 2,834	$ 3,290
Current	494,069	490,463
Total loans	496,903	493,753	$ 490,441
Total Loans 90 Days Past Due & Accruing	451	226
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	286	92
Current	146,214	143,275
Total loans	146,500	143,367	144,425
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	332	351
Current	84,493	83,895
Total loans	84,825	84,246	78,734
Total Loans 90 Days Past Due & Accruing	138
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	70	128
Current	7,644	7,008
Total loans	7,714	7,136	7,532
One- to four-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	1,700	2,251
Current	124,452	127,039
Total loans	126,152	129,290	130,518
Total Loans 90 Days Past Due & Accruing	313	226
Multi-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	415	422
Current	105,133	104,241
Total loans	105,548	104,663	107,625
Home equity lines of credit [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	31	46
Current	8,866	8,892
Total loans	8,897	8,938	9,033
Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	17,267	16,113
Total loans	17,267	16,113	$ 12,574
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	1,621	2,401
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	90	74
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	140	291
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	41	99
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	922	1,515
Financing Receivables, 30 to 59 Days Past Due [Member] | Multi-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	415	422
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	13
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	432	287
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	184	6
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	14
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	216	255
Financing Receivables, 60 to 89 Days Past Due [Member] | Home equity lines of credit [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	18	26
Financing Receivables, 90 Days or Greater [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	781	602
Financing Receivables, 90 Days or Greater [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	12	12
Financing Receivables, 90 Days or Greater [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	192	60
Financing Receivables, 90 Days or Greater [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	15	29
Financing Receivables, 90 Days or Greater [Member] | One- to four-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due	$ 562	481
Financing Receivables, 90 Days or Greater [Member] | Home equity lines of credit [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Past Due		$ 20