Income Taxes, Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Deferred tax assets [Abstract]
Allowance for loan losses	$ 4,220	$ 3,669
Pension benefits	310	689
Other benefit plans	1,957	1,137
Total deferred tax assets	6,487	5,495
Deferred tax liabilities [Abstract]
Depreciation	1,392	1,346
Loan costs	1,051	894
Real estate investment trust income	3,052	2,283
Unrealized gains on securities	379	771
Other	224	225
Total deferred tax liabilities	6,098	5,519
Net deferred tax asset included in prepaid expenses and other assets	389
Net deferred tax liability included in other liabilities		(24)
Income Tax Contingency [Line Items]
Uncertain tax positions	$ 0	$ 0
Federal [Member] | Earliest Tax Year [Member]
Income Tax Contingency [Line Items]
Open tax year	2014
Federal [Member] | Latest Tax Year [Member]
Income Tax Contingency [Line Items]
Open tax year	2016
New York State [Member] | Earliest Tax Year [Member]
Income Tax Contingency [Line Items]
Open tax year	2015
New York State [Member] | Latest Tax Year [Member]
Income Tax Contingency [Line Items]
Open tax year	2016