v3.21.2

FAIR VALUE MEASUREMENTS - Gross holding gains and fair value of held-to-maturity securities (Details) - U.S. Treasury Securities - Fair Value, Recurring - Level 1 | Dec. 31, 2020 USD ($)
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Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract] |
Amortized Cost | $ 1,035,848,884
Gross Holding Gain | 22,518
Fair Value | $ 1,035,871,402

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