Income Taxes - Schedule of Deferred Income Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Deferred income tax assets: Purchase accounting	$ 16,887	$ 17,116
Deferred income tax assets: Accumulated other comprehensive income - Defined benefit plans	251	228
Deferred income tax assets: Accumulated other comprehensive income - Unrealized loss on securities available for sale	2,313	1,159
Deferred income tax assets: Accumulated other comprehensive income - Unrealized loss on securities available for sale transferred to held to maturity	212	249
Deferred income tax assets: Allowance for loan losses	9,838	8,676
Deferred income tax assets: Benefit plans	1,484	1,842
Deferred income tax assets: Compensation	1,787	1,751
Deferred income tax assets: Stock-based compensation	1,887	2,050
Deferred income tax assets: Uncollected interest	1,062	1,018
Deferred income tax assets: Depreciation		1,169
Deferred income tax assets: Charitable contribution carryover	632	899
Deferred income tax assets: Net operating loss carryover	927	2,564
Capital loss carryforward	763	656
Deferred income tax assets: Other items	586	509
Deferred Tax Assets, Gross, Total	38,629	39,886
Deferred income tax assets: Valuation allowance	(946)	(791)
Deferred Tax Assets, Net of valuation allowance, Total	37,683	39,095
Deferred income tax liabilities: Deferred costs	1,685	1,551
Deferred income tax liabilities: Derivatives	6,521	8,961
Deferred income tax liabilities: Goodwill	4,578	4,385
Deferred income tax liabilities: Other items	207	444
Deferred Tax Liabilities, Gross, Total	12,991	15,341
Net deferred income tax asset	$ 24,692	$ 23,754