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Fair Value Measurement - Measurement Inputs (Details) - Valuation Technique, Discounted Cash Flow - Fair Value, Inputs, Level 3 | Mar. 31, 2021 | Dec. 31, 2020
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Minimum | Discount rate | Loans (at fair value) |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Loan receivable, measurement input | 0.0352 | 0.0680
Minimum | Discount rate | Notes Receivable |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Loan receivable, measurement input | 0.0301 | 0.0301
Minimum | Credit risk rate | Loans (at fair value) |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Loan receivable, measurement input | 0.0021 | 0.0036
Minimum | Credit risk rate | Notes Receivable |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Loan receivable, measurement input | 0.0004 | 0.0004
Minimum | Prepayment rate | Loans (at fair value) |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Loan receivable, measurement input | 0.1269 | 0.1164
Minimum | Prepayment rate | Notes Receivable |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Loan receivable, measurement input | 0.1560 | 0.1560
Maximum | Discount rate | Loans (at fair value) |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Loan receivable, measurement input | 0.1660 | 0.1699
Maximum | Discount rate | Notes Receivable |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Loan receivable, measurement input | 0.1400 | 0.1400
Maximum | Credit risk rate | Loans (at fair value) |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Loan receivable, measurement input | 0.5231 | 0.5231
Maximum | Credit risk rate | Notes Receivable |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Loan receivable, measurement input | 0.5069 | 0.5069
Maximum | Prepayment rate | Loans (at fair value) |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Loan receivable, measurement input | 0.7853 | 0.7836
Maximum | Prepayment rate | Notes Receivable |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Loan receivable, measurement input | 0.3688 | 0.3688
Weighted Average | Discount rate | Loans (at fair value) |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Loan receivable, measurement input | 0.0674 | 0.0744
Weighted Average | Discount rate | Notes Receivable |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Loan receivable, measurement input | 0.0583 | 0.0584
Weighted Average | Credit risk rate | Loans (at fair value) |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Loan receivable, measurement input | 0.2309 | 0.1982
Weighted Average | Credit risk rate | Notes Receivable |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Loan receivable, measurement input | 0.1740 | 0.1712
Weighted Average | Prepayment rate | Loans (at fair value) |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Loan receivable, measurement input | 0.3368 | 0.3103
Weighted Average | Prepayment rate | Notes Receivable |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Loan receivable, measurement input | 0.2767 | 0.2763

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