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Derivative Financial Instruments - Additional Information (Detail) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2020 | Mar. 31, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019 | Dec. 31, 2019
Derivative [Line Items] |  |  |  |  |  |
Weighted-average strike rate for outstanding interest rate caps |  |  |  | 3.67% |  |
Approximate credit exposure related to swaps with bank customers | $ 103,000 |  |  | $ 103,000 |  |
Cash collateral for borrowed securities deposited with other financial institutions | 48,600 |  |  | 48,600 |  |
Interest rate swaps with upstream financial institution counterparties [Member] |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Approximate credit exposure related to swaps with bank customers | 19,200 |  |  | 19,200 |  |
Not Designated as Hedging Instrument [Member] | Financial Institution Counterparties Loan Lease Interest Rate Swaps Liabilities [Member] |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Estimated fair value of derivative contracts cleared through Chicago Mercantile Exchange | 0 |  |  | 0 |  | $ 0
Notional Amount | 1,192,762 |  |  | 1,192,762 |  | $ 1,002,860
Other Income [Member] | Not Designated as Hedging Instrument [Member] | Put Option [Member] |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Amount of gain (loss) included in income | $ 0 | $ 6,000 | $ 0 | $ 5,980 | $ 0 |
US Treasury Securities [Member] | Not Designated as Hedging Instrument [Member] | Put Option [Member] |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Notional Amount |  | $ 500,000 |  |  |  |

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- Definition Carrying amount as of the balance sheet date of cash collateral held for borrowed securities, for which the cash is restricted as to withdrawal or usage. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.1) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.(a),2) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 + Details
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- Definition Maximum potential amount of future undiscounted payments that could be required under the credit derivative, before reduction for potential recoveries under recourse or collateralization provisions. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4K -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5708775-113959 + Details
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