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Federal Funds Purchased and Securities Sold Under Agreement to Repurchase - Daily Securities Sold under Agreement to Repurchase (Detail) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2018 | Dec. 31, 2017
Schedule of Trading Securities and Other Trading Assets [Line Items] |  |
Amount Outstanding at End of Period | $ 25,700 |
Daily Securities Sold Under Agreement to Repurchase [Member] |  |
Schedule of Trading Securities and Other Trading Assets [Line Items] |  |
Amount Outstanding at End of Period | $ 806 | $ 6,145
Weighted Average Rate End of Period | 1.04% | 1.19%
Maximum Amount Borrowings Outstanding Month End | $ 819 | $ 14,929
Approximate Average Outstanding in Period | $ 1,026 | $ 10,253
Approximate Weighted Average Interest Rate For the Period | 1.12% | 0.96%
Term CDs Sold Under Agreement to Repurchase [Member] |  |
Schedule of Trading Securities and Other Trading Assets [Line Items] |  |
Amount Outstanding at End of Period | $ 24,889 | $ 22,925
Weighted Average Rate End of Period | 2.00% | 1.97%
Maximum Amount Borrowings Outstanding Month End | $ 24,889 | $ 22,925
Approximate Average Outstanding in Period | $ 23,793 | $ 21,172
Approximate Weighted Average Interest Rate For the Period | 1.87% | 1.81%

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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. + Details
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- Definition Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=49176635&loc=d3e9760-107771 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.13(1)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(m)(1)(a)(i)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
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