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Derivative Financial Instruments - Additional Information (Detail) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2021 | Jun. 30, 2020 | Mar. 31, 2020 | Jun. 30, 2021 | Jun. 30, 2020 | Dec. 31, 2020
Derivative [Line Items] |  |  |  |  |  |
Weighted-average strike rate for outstanding interest rate caps |  |  |  | 3.26% |  |
Approximate credit exposure related to swaps with bank customers | $ 197,400 |  |  | $ 197,400 |  |
Cash collateral for borrowed securities deposited with other financial institutions | 175,400 |  |  | 175,400 |  |
Interest rate swaps with upstream financial institution counterparties [Member] |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Approximate credit exposure related to swaps with bank customers | 14,200 |  |  | 14,200 |  |
Eurodollar Future | Financial Institution Counterparties [Member] |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Forward Contracts – Assets Estimated Fair Value | 0 |  |  | 0 |  | $ 0
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
Other Income [Member] | Not Designated as Hedging Instrument [Member] | Put Option [Member] |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Amount of gain (loss) included in income | $ 0 | $ 0 | $ 6,000 | $ 0 | $ 5,980 |
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 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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