Variable Interest Entities and Securitized Debt Obligations - Schedule of Variable Interest Entities (Details) - USD ($) |
Jun. 30, 2026 |
Mar. 31, 2026 |
Dec. 31, 2025 |
Jun. 30, 2025 |
Mar. 31, 2025 |
Dec. 31, 2024 |
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| Variable Interest Entity [Line Items] | ||||||||
| Loans held-for-investment | $ 1,389,380,000 | $ 1,510,097,000 | $ 1,683,644,000 | $ 1,823,279,000 | $ 1,937,659,000 | $ 2,097,375,000 | ||
| Allowance for credit losses | (163,484,000) | (147,298,000) | (145,912,000) | (151,968,000) | (177,282,000) | (199,727,000) | ||
| Loans held-for-investment, net | 1,225,896,000 | $ 1,362,799,000 | 1,537,732,000 | $ 1,671,311,000 | $ 1,760,377,000 | $ 1,897,648,000 | ||
| Restricted cash | 48,994,000 | 14,108,000 | ||||||
| Other assets | 31,786,000 | 37,793,000 | ||||||
| Total Assets | [1] | 1,462,754,000 | 1,755,224,000 | |||||
| Securitized debt obligations | 521,646,000 | 643,528,000 | ||||||
| Other liabilities | 15,898,000 | 24,227,000 | ||||||
| Total Liabilities | [1] | 982,357,000 | 1,202,412,000 | |||||
| Collateral assets(2) | ||||||||
| Variable Interest Entity [Line Items] | ||||||||
| Securitized debt obligations | 672,153,000 | 801,997,000 | ||||||
| Collateral assets(2) | Asset Pledged as Collateral | CRE CLO financing activities | ||||||||
| Variable Interest Entity [Line Items] | ||||||||
| Restricted cash | 48,700,000 | |||||||
| Collateral assets(2) | GPMT 2021-FL4 CRE CLO | ||||||||
| Variable Interest Entity [Line Items] | ||||||||
| Securitized debt obligations | 399,105,000 | 446,569,000 | ||||||
| Collateral assets(2) | GPMT 2021-FL4 CRE CLO | Asset Pledged as Collateral | CRE CLO financing activities | ||||||||
| Variable Interest Entity [Line Items] | ||||||||
| Restricted cash | 11,200,000 | 31,000.0 | ||||||
| Collateral assets(2) | GPMT 2021-FL3 CRE CLO | ||||||||
| Variable Interest Entity [Line Items] | ||||||||
| Securitized debt obligations | 273,048,000 | 355,428,000 | ||||||
| Collateral assets(2) | GPMT 2021-FL3 CRE CLO | Asset Pledged as Collateral | CRE CLO financing activities | ||||||||
| Variable Interest Entity [Line Items] | ||||||||
| Restricted cash | 37,500,000 | 0 | ||||||
| Variable Interest Entity, Primary Beneficiary | ||||||||
| Variable Interest Entity [Line Items] | ||||||||
| Loans held-for-investment | 644,975,000 | 823,655,000 | ||||||
| Allowance for credit losses | (21,500,000) | (21,689,000) | ||||||
| Loans held-for-investment, net | 623,475,000 | 801,966,000 | ||||||
| Restricted cash | 48,679,000 | 31,000.0 | ||||||
| Other assets | 5,487,000 | 5,054,000 | ||||||
| Total Assets | 677,641,000 | 807,051,000 | ||||||
| Securitized debt obligations | 521,646,000 | 643,528,000 | ||||||
| Other liabilities | 884,000 | 1,273,000 | ||||||
| Total Liabilities | $ 522,530,000 | $ 644,801,000 | ||||||
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- Definition Amount of asset recognized for present right to economic benefit. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Obligation reflecting another party's right to economic interests in another entity or trust under a contractual right. For example, an investor may purchase a beneficial interest in a securitization transaction. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amortized cost excluding accrued interest, after allowance for credit loss, of financing receivable. Excludes net investment in lease. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of liability recognized for present obligation requiring transfer or otherwise providing economic benefit to others. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount of assets classified as other. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of liabilities classified as other. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of cash restricted as to withdrawal or usage. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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