Investment Securities Held to Maturity - Investments Gross Unrecognized Losses and Fair Value (Detail) $ in Thousands	Dec. 31, 2019 USD ($)
Schedule of Held-to-maturity Securities [Line Items]
12 months or more, Fair Value	$ 8,445
12 months or more, Unrecognized Losses	29
Total, Fair Value	8,445
Total, Unrecognized Losses	29
Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
12 months or more, Fair Value	8,445
12 months or more, Unrecognized Losses	29
Total, Fair Value	8,445
Total, Unrecognized Losses	$ 29

Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), in continuous loss position for 12 months or longer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27337-111563

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27290-111563

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- Definition

Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), in unrealized loss position.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27290-111563

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- Definition

Fair value of investment in debt security measured at amortized cost (held-to-maturity), in unrealized loss position.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27290-111563

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- Definition

Fair value of investment in debt security measured at amortized cost (held-to-maturity), in continuous unrealized loss position for 12 months or longer.

+ References

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