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Impairment of Securities - Schedule of Temporary Impairment Losses, Investments (Detail) $ in Thousands		Sep. 30, 2019 USD ($) Security	Jun. 30, 2019 USD ($) Security
Schedule Of Held To Maturity Securities [Line Items]
Less than 12 Months: Fair Value		$ 2,975	$ 712
Less than 12 Months: Unrecognized Losses		6	2
12 Months or More: Fair Value		470	95,196
12 Months or More: Unrecognized Losses		$ 1	$ 706
Number of Securities | Security		10	96
Total: Fair Value		$ 3,445	$ 95,908
Total: Unrecognized Losses		7	708
Debt Securities [Member]
Schedule Of Held To Maturity Securities [Line Items]
Total: Unrecognized Losses		7	16
Debt Securities [Member] | Obligations of State and Political Subdivisions [Member]
Schedule Of Held To Maturity Securities [Line Items]
Less than 12 Months: Fair Value		2,975	274
Less than 12 Months: Unrecognized Losses		6	1
12 Months or More: Fair Value		470	7,149
12 Months or More: Unrecognized Losses		$ 1	$ 15
Number of Securities | Security		10	19
Total: Fair Value		$ 3,445	$ 7,423
Total: Unrecognized Losses		$ 7	16
Collateralized Mortgage Obligations Excluding Pass Through Securities [Member]
Schedule Of Held To Maturity Securities [Line Items]
12 Months or More: Fair Value			9,347
12 Months or More: Unrecognized Losses			$ 168
Number of Securities | Security			5
Total: Fair Value			$ 9,347
Total: Unrecognized Losses	[1]		168
Residential Pass-Through Securities [Member]
Schedule Of Held To Maturity Securities [Line Items]
Less than 12 Months: Fair Value			438
Less than 12 Months: Unrecognized Losses			1
12 Months or More: Fair Value			76,848
12 Months or More: Unrecognized Losses			$ 517
Number of Securities | Security			70
Total: Fair Value			$ 77,286
Total: Unrecognized Losses	[1]		518
Commercial Pass-Through Securities [Member]
Schedule Of Held To Maturity Securities [Line Items]
12 Months or More: Fair Value			1,852
12 Months or More: Unrecognized Losses			$ 6
Number of Securities | Security			2
Total: Fair Value			$ 1,852
Total: Unrecognized Losses	[1]		$ 6
[1] Government-sponsored enterprises.

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