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Securities - Amortized Cost and Fair Value of Debt Securities, by Contractual Maturity (Detail) - USD ($) $ in Thousands | Sep. 30, 2018 | Dec. 31, 2017
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Available For Sale Securities Debt Maturities [Abstract] |  |
Amortized Cost, One year or less | $ 34,797 |
Amortized Cost, After one year through five years | 70,423 |
Amortized Cost, After five years through ten years | 44,678 |
Amortized Cost, After ten years | 3,036 |
Amortized Cost, Total | 152,934 |
Amortized Cost, Mortgage-backed securities | 36,350 |
Amortized Cost | 189,284 | $ 199,165
Fair Value, One year or less | 34,563 |
Fair Value, After one year through five years | 68,544 |
Fair Value, After five years through ten years | 42,533 |
Fair Value, After ten years | 2,835 |
Fair Value, Total | 148,475 |
Fair Value, Mortgage-backed securities | 34,600 |
Total, Fair Value | $ 183,075 | $ 196,398

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- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth fiscal year through tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27198-111563 + Details
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