Schedule IV - Mortgage Loans on Real Estate Mortgage Loans on Real Estate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest Rates	8.82%	5.65%
Prior Liens	$ 564,472
Face amount of Mortgages	3,938,646
Carrying Amount of Mortgages	3,892,382	$ 3,521,985	$ 2,343,070
Principal Amount of Mortgages Subject to Delinquent Principal or Interest	56,509
Total carrying amount of mortgages	3,913,137
Provision for loan losses	(20,755)
Principal balance of loans on non-accrual status	53,800
Aggregate cost for U.S. federal tax income purposes	3,800,000
Mortgage loans held for sale	3,892,382	3,521,985	2,343,070
Mortgage loan receivables held for investment, net, at amortized cost:
Mortgage loans receivable, beginning balance	3,521,985	2,343,070	3,358,861
Beginning balance, Allowance for credit losses	(31,752)	(41,507)	(20,500)
Origination of mortgage loan receivables	1,296,083	2,530,247	566,506
Purchases of mortgage loan receivables	0
Repayment of mortgage loan receivables	(901,150)	(1,059,979)	(961,236)
Proceeds from sales of mortgage loan receivables	(29,151)	(305,649)	(582,764)
Non-cash disposition of loan via foreclosure	(10,235)	(81,289)	(31,249)
Realized gain on sale of mortgage loan receivables	(2,511)	8,398	(1,571)
Accretion/amortization of discount, premium and other fees	20,759	13,832	15,530
Release (addition) of provision for current expected credit loss, net	(3,711)	8,713	(18,275)
Release of asset-specific loan loss provision via foreclosure		1,150	2,500
Provision expense for current expected credit loss (implementation impact)			(4,964)
Provision expense for current expected credit loss (impact to earnings)	(3,398)	8,605	(18,543)
Mortgage loans receivable, ending balance	3,892,382	3,521,985	2,343,070
Ending balance, Allowance for credit losses	(20,755)	(31,752)	(41,507)
Provision for (release of) loan loss reserves, net	14,395		18,275
Mortgage loan  receivables held for sale
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Carrying Amount of Mortgages	27,400
Mortgage loans held for sale	27,400
Mortgage loan receivables held for investment, net, at amortized cost:
Mortgage loans receivable, ending balance	27,400
Total mortgage loan receivables held for investment, net, at amortized cost
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Carrying Amount of Mortgages	3,885,746	3,553,737	2,354,059
Mortgage loans held for sale	3,885,746	3,553,737	2,354,059
Mortgage loan receivables held for investment, net, at amortized cost:
Mortgage loans receivable, beginning balance	3,553,737	2,354,059	3,257,036
Beginning balance, Allowance for credit losses	(31,752)	(41,507)	(20,500)
Origination of mortgage loan receivables	1,234,765	2,309,888	353,661
Purchases of mortgage loan receivables	0	63,600
Repayment of mortgage loan receivables	(901,082)	(1,059,796)	(960,832)
Proceeds from sales of mortgage loan receivables	0	(46,557)	(270,491)
Non-cash disposition of loan via foreclosure	(10,235)	(81,289)	(31,249)
Realized gain on sale of mortgage loan receivables	2,197	0	(9,596)
Accretion/amortization of discount, premium and other fees	20,759	13,832	15,530
Release (addition) of provision for current expected credit loss, net		8,605
Release of asset-specific loan loss provision via foreclosure		1,150	2,500
Provision expense for current expected credit loss (implementation impact)			(4,964)
Provision expense for current expected credit loss (impact to earnings)	(3,398)	8,605	(18,543)
Mortgage loans receivable, ending balance	3,885,746	3,553,737	2,354,059
Ending balance, Allowance for credit losses	$ (20,755)	(31,752)	(41,507)
Mortgage loan  receivables held for sale
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest Rates	4.57%
Carrying Amount of Mortgages	$ 27,391	0	30,518
Mortgage loans held for sale	27,391	0	30,518
Mortgage loan receivables held for investment, net, at amortized cost:
Mortgage loans receivable, beginning balance	0	30,518	122,325
Origination of mortgage loan receivables	61,318	220,359	212,845
Purchases of mortgage loan receivables	0	0
Repayment of mortgage loan receivables	(68)	(183)	(404)
Proceeds from sales of mortgage loan receivables	(29,151)	(259,092)	(312,273)
Non-cash disposition of loan via foreclosure		0	0
Realized gain on sale of mortgage loan receivables	(4,708)	8,398	8,025
Accretion/amortization of discount, premium and other fees		0	0
Mortgage loans receivable, ending balance	27,391	$ 0	$ 30,518
First mortgage loan
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Prior Liens	0
Face amount of Mortgages	3,872,696
Carrying Amount of Mortgages	3,847,251
Principal Amount of Mortgages Subject to Delinquent Principal or Interest	56,509
Mortgage loans held for sale	3,847,251
Mortgage loan receivables held for investment, net, at amortized cost:
Mortgage loans receivable, ending balance	3,847,251
Second Mortgage
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Prior Liens	564,472
Face amount of Mortgages	65,950
Carrying Amount of Mortgages	65,886
Principal Amount of Mortgages Subject to Delinquent Principal or Interest	0
Mortgage loans held for sale	65,886
Mortgage loan receivables held for investment, net, at amortized cost:
Mortgage loans receivable, ending balance	65,886
Office, Mixed | First Mortgages individually greater than 3%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Prior Liens	0
Face amount of Mortgages	373,468
Carrying Amount of Mortgages	371,489
Principal Amount of Mortgages Subject to Delinquent Principal or Interest	0
Mortgage loans held for sale	371,489
Mortgage loan receivables held for investment, net, at amortized cost:
Mortgage loans receivable, ending balance	$ 371,489
Office, Mixed | Minimum | First Mortgages individually greater than 3%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest Rates	7.75%
Office, Mixed | Maximum | First Mortgages individually greater than 3%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest Rates	8.30%
Mixed, Office, Multi-Family, Industrial, Hotel, Mobile Home Park, Retail, Land | First Mortgages individually less than 3%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Prior Liens	$ 0
Face amount of Mortgages	3,499,228
Carrying Amount of Mortgages	3,475,762
Principal Amount of Mortgages Subject to Delinquent Principal or Interest	56,509
Mortgage loans held for sale	3,475,762
Mortgage loan receivables held for investment, net, at amortized cost:
Mortgage loans receivable, ending balance	$ 3,475,762
Mixed, Office, Multi-Family, Industrial, Hotel, Mobile Home Park, Retail, Land | Minimum | First Mortgages individually less than 3%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest Rates	4.25%
Mixed, Office, Multi-Family, Industrial, Hotel, Mobile Home Park, Retail, Land | Maximum | First Mortgages individually less than 3%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest Rates	13.40%
Multi-Family, Hotel, Office | Subordinated Mortgages individually less than 3%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Prior Liens	$ 564,472
Face amount of Mortgages	65,950
Carrying Amount of Mortgages	65,886
Principal Amount of Mortgages Subject to Delinquent Principal or Interest	0
Mortgage loans held for sale	65,886
Mortgage loan receivables held for investment, net, at amortized cost:
Mortgage loans receivable, ending balance	$ 65,886
Multi-Family, Hotel, Office | Minimum | Subordinated Mortgages individually less than 3%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest Rates	9.00%
Multi-Family, Hotel, Office | Maximum | Subordinated Mortgages individually less than 3%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest Rates	12.00%