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Derivative Financial Instruments - Additional Information (Details) | 3 Months Ended |  |  |
--- | --- | --- | --- | ---
Mar. 31, 2020 USD ($) | Sep. 30, 2020 USD ($) | Dec. 31, 2019 USD ($) | Dec. 31, 2018 instrument
Other assets |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative assets, gross |  | $ 2,600,000 | $ 2,200,000 |
Other liabilities |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative liabilities, gross |  | 4,000,000.0 | 1,000,000.0 |
Forward contracts |  |  |  |
Derivative [Line Items] |  |  |  |
Cash collateral held from counterparty |  | 0 | 8,700,000 |
Cash collateral held at counterparty |  | $ 2,200,000 | 0 |
Foreign contracts and collar contracts |  |  |  |
Derivative [Line Items] |  |  |  |
Proceeds from derivative termination | $ 24,900,000 |  |  |
Foreign contracts and collar contracts | Other assets |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative assets, net |  |  | $ 5,700,000 |
Designated as Hedging Instrument | Net Investment Hedging | Forward contracts |  |  |  |
Derivative [Line Items] |  |  |  |
Number of instruments held | instrument |  |  |  | 2
Designated as Hedging Instrument | Net Investment Hedging | Collar |  |  |  |
Derivative [Line Items] |  |  |  |
Number of instruments held | instrument |  |  |  | 2
Designated as Hedging Instrument | Cash Flow Hedging | Interest rate swap |  |  |  |
Derivative [Line Items] |  |  |  |
Fixed interest rate | 0.5135% |  |  |
Derivative notional amount | $ 250,000,000.0 |  |  |

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