Securities - Additional Information (Detail) - USD ($)	3 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2018
Debt Securities, Available-for-sale [Line Items]
Mortgage-backed securities with a book value	$ 131,792,000		$ 130,236,000
Fair Value	$ 126,241,000		125,996,000
Percentage of equity securities	10.00%
Carrying value of securities pledged as collateral	$ 69,135,000		64,625,000
Repurchase agreements	2,134,000		2,281,000
Gross gains from sales of available for sale securities		$ 20,000
Gross losses from sales of available for sale securities		7,000
Tax benefit to net realized gains	0	5,000
Sales of available-for-sale securities	0	$ 13,000
Investments in debt and marketable equity securities	$ 120,276,000		$ 119,180,000
Temporarily impaired debt securities percentage of investment securities portfolio	95.00%		95.00%
Unrealized losses on investments	$ 0
Maturity Overnight [Member]
Debt Securities, Available-for-sale [Line Items]
Repurchase agreements	234,000
Maturity 30 to 90 Days [Member]
Debt Securities, Available-for-sale [Line Items]
Repurchase agreements	$ 1,900,000
Minimum [Member]
Debt Securities, Available-for-sale [Line Items]
Repurchase agreements term	30 days
Maximum [Member]
Debt Securities, Available-for-sale [Line Items]
Repurchase agreements term	90 days
'U.S. Government and Federal Agency and Government Sponsored Enterprises (GSEs) [Member]
Debt Securities, Available-for-sale [Line Items]
Mortgage-backed securities with a book value	$ 24,769,000		$ 24,757,000
Fair Value	23,695,000		23,922,000
Investments in debt and marketable equity securities	23,695,000		23,922,000
Mortgage-backed Securities - GSE Residential [Member]
Debt Securities, Available-for-sale [Line Items]
Mortgage-backed securities with a book value	98,661,000		100,534,000
Fair Value	94,192,000		97,059,000
Investments in debt and marketable equity securities	91,314,000		93,367,000
Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investments in debt and marketable equity securities	$ 120,276,000		$ 119,180,000

Debt securities greater than stated percentage of equity securities.

No definition available.

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Repurchase agreement term period.

+ References

No definition available.

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- Definition

Temporarily impaired debt securities percentage of investment securities portfolio.

+ References

No definition available.

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- Definition

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

No definition available.

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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No definition available.

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This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities.

+ References

No definition available.

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This item represents the difference between the gross realized gains and losses realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Additionally, this item would include any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt and equity securities.

+ References

No definition available.

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This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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No definition available.

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This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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No definition available.

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- Definition

Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

+ References

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- Definition

The sum of the fair values, as of the date of each statement of financial position presented, of securities that are restricted as collateral for the payment of related debt obligations, primarily secured borrowings and repurchase agreements, and that are reclassified and separately reported in the statement of financial position because the transferee has the right by contract or custom to sell or re-pledge them.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Carrying value, as of the balance sheet date, of securities sold under agreements to repurchase where the transferor maintains effective control over the assets, accounting for them as secured debt.

+ References

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The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of investments, not including unrealized gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity, held at each balance sheet date and included in earnings for the period.

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