Loans Receivable - Credit Quality Indicators by Class of Loan (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Jun. 30, 2017
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 734,235	$ 733,997
Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	700,538	701,562
Watch
Financing Receivable, Recorded Investment [Line Items]
Loans	21,562	19,838
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	8,881	9,345
Sub- Standard
Financing Receivable, Recorded Investment [Line Items]
Loans	3,254	3,252
Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans	1,794	1,915
Performing
Financing Receivable, Recorded Investment [Line Items]
Loans	732,441	732,082
Real Estate
Financing Receivable, Recorded Investment [Line Items]
Loans	659,462	660,012
Real Estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	629,653	631,830
Real Estate | Watch
Financing Receivable, Recorded Investment [Line Items]
Loans	19,528	18,000
Real Estate | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	7,705	7,664
Real Estate | Sub- Standard
Financing Receivable, Recorded Investment [Line Items]
Loans	2,576	2,518
Real Estate | Real estate loans | One-to-four family
Financing Receivable, Recorded Investment [Line Items]
Loans	323,675	328,243
Real Estate | Real estate loans | One-to-four family | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	316,469	321,596
Real Estate | Real estate loans | One-to-four family | Watch
Financing Receivable, Recorded Investment [Line Items]
Loans	4,340	3,680
Real Estate | Real estate loans | One-to-four family | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	959	1,153
Real Estate | Real estate loans | One-to-four family | Sub- Standard
Financing Receivable, Recorded Investment [Line Items]
Loans	1,907	1,814
Real Estate | Real estate loans | One-to-four family | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans	975	1,042
Real Estate | Real estate loans | One-to-four family | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans	322,700	327,201
Real Estate | Real estate loans | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Loans	58,989	58,101
Real Estate | Real estate loans | Multi-family | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	56,756	56,103
Real Estate | Real estate loans | Multi-family | Watch
Financing Receivable, Recorded Investment [Line Items]
Loans	2,117	1,880
Real Estate | Real estate loans | Multi-family | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	116	118
Real Estate | Real estate loans | Multi-family | Sub- Standard
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Real Estate | Real estate loans | Multi-family | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Real Estate | Real estate loans | Multi-family | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans	58,989	58,101
Real Estate | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans	194,813	202,038
Real Estate | Commercial real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	182,417	188,956
Real Estate | Commercial real estate | Watch
Financing Receivable, Recorded Investment [Line Items]
Loans	9,611	10,243
Real Estate | Commercial real estate | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	2,209	2,232
Real Estate | Commercial real estate | Sub- Standard
Financing Receivable, Recorded Investment [Line Items]
Loans	576	607
Real Estate | Commercial real estate | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans	403	426
Real Estate | Commercial real estate | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans	194,410	201,612
Real Estate | Construction and land
Financing Receivable, Recorded Investment [Line Items]
Loans	81,985	71,630
Real Estate | Construction and land | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	74,011	65,175
Real Estate | Construction and land | Watch
Financing Receivable, Recorded Investment [Line Items]
Loans	3,460	2,197
Real Estate | Construction and land | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	4,421	4,161
Real Estate | Construction and land | Sub- Standard
Financing Receivable, Recorded Investment [Line Items]
Loans	93	97
Real Estate | Construction and land | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans	27	28
Real Estate | Construction and land | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans	81,958	71,602
Consumer
Financing Receivable, Recorded Investment [Line Items]
Loans	58,388	56,912
Consumer | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	56,881	55,589
Consumer | Watch
Financing Receivable, Recorded Investment [Line Items]
Loans	624	374
Consumer | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	205	230
Consumer | Sub- Standard
Financing Receivable, Recorded Investment [Line Items]
Loans	678	719
Consumer | Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans	35,059	35,869
Consumer | Home equity | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	34,076	34,913
Consumer | Home equity | Watch
Financing Receivable, Recorded Investment [Line Items]
Loans	318	215
Consumer | Home equity | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	33	57
Consumer | Home equity | Sub- Standard
Financing Receivable, Recorded Investment [Line Items]
Loans	632	684
Consumer | Home equity | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans	377	398
Consumer | Home equity | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans	34,682	35,471
Consumer | Other
Financing Receivable, Recorded Investment [Line Items]
Loans	23,329	21,043
Consumer | Other | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	22,805	20,676
Consumer | Other | Watch
Financing Receivable, Recorded Investment [Line Items]
Loans	306	159
Consumer | Other | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	172	173
Consumer | Other | Sub- Standard
Financing Receivable, Recorded Investment [Line Items]
Loans	46	35
Consumer | Other | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans	12	21
Consumer | Other | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans	23,317	21,022
Commercial business
Financing Receivable, Recorded Investment [Line Items]
Loans	16,385	17,073
Commercial business | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	14,004	14,143
Commercial business | Watch
Financing Receivable, Recorded Investment [Line Items]
Loans	1,410	1,464
Commercial business | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	971	1,451
Commercial business | Sub- Standard
Financing Receivable, Recorded Investment [Line Items]
Loans	0	15
Commercial business | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial business | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 16,385	$ 17,073