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Derivatives - Additional Information (Detail) $ in Thousands | 12 Months Ended
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Dec. 31, 2018 USD ($) Derivative | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($)
Derivative [Line Items] |  |  |
Number of participation agreements for interest rate swaps, participant | Derivative | 31 |  |
Number of participation agreements for interest rate swaps, lead bank | Derivative | 10 |  |
Derivative, Gain (Loss) on Derivative, Net | $ 787 | $ (473) | $ 219
Interest Rate Swap [Member] | Cash Flow Hedging [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative, notional amount | 65,000 |  |
Collateral Already Posted, Aggregate Fair Value | 65,000 |  |
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative, notional amount | 65,000 | 150,000 |
Interest Rate Swap [Member] | Interest Income [Member] | Designated as Hedging Instrument [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative, Gain (Loss) on Derivative, Net | (590) | 452 | 1,627
Interest Rate Swap [Member] | Other Income [Member] | Designated as Hedging Instrument [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative, Gain (Loss) on Derivative, Net | 10 | 119 | 70
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative, notional amount | 1,927 | 10,077 |
Derivative, Underlying Asset Carrying Value | 1,900 | 10,000 |
Derivative Liability, Fair Value, Gross Asset | 1,900 | 10,100 |
Foreign Exchange Contract [Member] | Other Income [Member] | Designated as Hedging Instrument [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative, Gain (Loss) on Derivative, Net | 15 | 4 | (5)
Forward Contracts [Member] | Designated as Hedging Instrument [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative, notional amount | 15,000 | 17,000 |
Derivative, Underlying Asset Carrying Value | 6,900 | 14,300 |
Derivative Liability, Fair Value, Gross Asset | 7,600 | 14,700 |
Derivative Liability, Notional Amount | 9,900 | 13,800 |
Forward Contracts [Member] | Other Income [Member] | Designated as Hedging Instrument [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative, Gain (Loss) on Derivative, Net | $ (189) | $ (19) | $ 0
Four Year [Member] | Interest Rate Swap [Member] | Cash Flow Hedging [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative, Term of Contract | 4 years |  |

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- Definition Derivative, Underlying Asset Carrying Value + References No definition available. + Details
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- Definition Derivative, Underlying Asset Fair Value + References No definition available. + Details
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- Definition Number of Participation Agreements, Interest Rate Derivatives Held as a Participant + References No definition available. + Details
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- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B + Details
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- Definition The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4H -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624258-113959 + Details
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- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959 + Details
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- Definition Nominal or face amount used to calculate payments on the derivative liability. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959 + Details
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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 Period the derivative contract is outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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- Definition Number of interest rate derivative instruments held by the entity at the reporting date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959 + Details
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