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Summarized Information on Location and Gross Amount of Derivatives on Consolidated Balance Sheets (Detail) - Not Designated as Hedging Instrument - Other Assets Liabilities - USD ($) $ in Thousands | Sep. 30, 2020 | Dec. 31, 2019
--- | --- | ---
Derivatives, Fair Value [Line Items] |  |  |
Notional Amount |  | $ 230,418 | $ 274,710
Fair Value |  | (17,931) | (10,275)
Interest Rate Swap |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Notional Amount |  | 200,000 | 200,000
Fair Value |  | (17,931) | (10,275)
Futures Contracts on Bonds |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Notional Amount | [1] | 30,418 | 16,894
Fair Value | [1] | 0 | 0
Futures Contracts on Equities |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Notional Amount | [1] | 0 | 57,816
Fair Value | [1] | $ 0 | $ 0
[1] | Futures are settled daily such that their fair value is not reflected in the consolidated statements of financial position

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- Definition Fair value as of the balance sheet date of derivative instrument not designated as hedging instrument and classified as a liability. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624163-113959 + Details
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- Definition Nominal or face amount used to calculate payment on derivative. + References Reference 1: 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=121590274&loc=SL5580258-113959 Reference 2: 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=121590274&loc=SL5579245-113959 + Details
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