Concentration of Credit Risk - Summary of Loans Held for Investment Portfolio by Loan Category Type (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Loans And Leases Receivable Disclosure [Line Items]
Loan commitment	$ 4,869,045	$ 5,429,146
Unfunded commitment	$ 300,502	$ 426,061
% of loan commitment	100.00%	100.00%
Total unpaid principal balance	$ 4,567,250	$ 5,004,798
% of loan UPB	100.00%	100.00%
Bridge
Loans And Leases Receivable Disclosure [Line Items]
Loan commitment	$ 2,228,000	$ 1,524,284
Unfunded commitment	$ 44,565	$ 225,914
% of loan commitment	45.80%	28.10%
Total unpaid principal balance	$ 2,183,436	$ 1,299,541
% of loan UPB	47.70%	26.00%
Moderate Transitional
Loans And Leases Receivable Disclosure [Line Items]
Loan commitment	$ 1,515,794	$ 2,249,442
Unfunded commitment	$ 178,175	$ 52,588
% of loan commitment	31.10%	41.40%
Total unpaid principal balance	$ 1,336,325	$ 2,197,397
% of loan UPB	29.30%	43.90%
Light Transitional
Loans And Leases Receivable Disclosure [Line Items]
Loan commitment	$ 1,074,651	$ 1,604,820
Unfunded commitment	$ 57,464	$ 125,959
% of loan commitment	22.10%	29.60%
Total unpaid principal balance	$ 1,017,187	$ 1,478,860
% of loan UPB	22.30%	29.50%
Construction
Loans And Leases Receivable Disclosure [Line Items]
Loan commitment	$ 50,600	$ 50,600
Unfunded commitment	$ 20,298	$ 21,600
% of loan commitment	1.00%	0.90%
Total unpaid principal balance	$ 30,302	$ 29,000
% of loan UPB	0.70%	0.60%