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Short-term Borrowings - Interest Expense on Short-Term Borrowings (Detail) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Interest On Short Term Borrowings [Line Items] |  |  |
Total interest on short-term borrowings | $ 10,741 | $ 8,799 | $ 8,076
Federal funds purchased |  |  |
Interest On Short Term Borrowings [Line Items] |  |  |
Total interest on short-term borrowings | 180 | 77 | 41
Borrowings from FHLB |  |  |
Interest On Short Term Borrowings [Line Items] |  |  |
Total interest on short-term borrowings | 9,929 | 8,360 | 7,765
Securities sold under agreements to repurchase |  |  |
Interest On Short Term Borrowings [Line Items] |  |  |
Total interest on short-term borrowings | $ 632 | $ 362 | $ 270

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- Definition The aggregate interest expense incurred on short-term borrowings including commercial paper and Federal funds purchased and securities sold under agreements to repurchase. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.7) -URI http://asc.fasb.org/extlink&oid=114873765&loc=SL114874048-224260 + Details
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