Loans Receivable - Summary of Risk Category of Loans by Portfolio Segment (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Jun. 30, 2019
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 1,227,298	$ 1,096,977
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,216,874	1,076,801
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,464	11,716
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,960	8,460
Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	266,684	265,167
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	775,378	651,396
Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	24,929	13,231
Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	128,869	133,614
Home Equity Lines Of Credit [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	30,994	33,204
Consumer and Overdrafts [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	444	365
Originated [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,142,132	995,170
Originated [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,134,080	982,591
Originated [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,205	7,900
Originated [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,847	4,679
Originated [Member] | Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	226,457	218,056
Originated [Member] | Residential [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	224,719	216,438
Originated [Member] | Residential [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	481	1,071
Originated [Member] | Residential [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,257	547
Originated [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	733,781	600,675
Originated [Member] | Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	733,449	600,216
Originated [Member] | Commercial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	332	339
Originated [Member] | Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans		120
Originated [Member] | Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	24,929	13,231
Originated [Member] | Construction [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	24,929	13,231
Originated [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	128,683	133,436
Originated [Member] | Commercial Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	123,174	123,361
Originated [Member] | Commercial Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	3,986	6,423
Originated [Member] | Commercial Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,523	3,652
Originated [Member] | Home Equity Lines Of Credit [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	27,855	29,423
Originated [Member] | Home Equity Lines Of Credit [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	27,382	28,996
Originated [Member] | Home Equity Lines Of Credit [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	406	67
Originated [Member] | Home Equity Lines Of Credit [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	67	360
Originated [Member] | Consumer and Overdrafts [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	427	349
Originated [Member] | Consumer and Overdrafts [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	427	349
Acquired [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	85,166	101,807
Acquired [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	82,794	94,210
Acquired [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	259	3,816
Acquired [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,113	3,781
Acquired [Member] | Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	40,227	47,111
Acquired [Member] | Residential [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	39,171	44,959
Acquired [Member] | Residential [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	201	211
Acquired [Member] | Residential [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	855	1,941
Acquired [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	41,597	50,721
Acquired [Member] | Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	40,720	45,726
Acquired [Member] | Commercial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans		3,537
Acquired [Member] | Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	877	1,458
Acquired [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	186	178
Acquired [Member] | Commercial Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	186	178
Acquired [Member] | Home Equity Lines Of Credit [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	3,139	3,781
Acquired [Member] | Home Equity Lines Of Credit [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,700	3,331
Acquired [Member] | Home Equity Lines Of Credit [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	58	68
Acquired [Member] | Home Equity Lines Of Credit [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	381	382
Acquired [Member] | Consumer and Overdrafts [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	17	16
Acquired [Member] | Consumer and Overdrafts [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 17	$ 16