MORTGAGE LOAN RECEIVABLES - Individually Impaired Loans (Details) - USD ($) $ in Thousands		Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	[1]	$ 3,885,746	$ 3,553,737
Subtotal loans, Year One		1,145,229	2,396,303
Subtotal loans, Year Two		2,102,307	117,367
Subtotal loans, Year Three		56,150	585,959
Subtotal loans, Year Four		332,046	169,948
Subtotal loans, Year 5 and Earlier		224,002	214,228
Subtotal mortgage loans receivable		3,859,734	3,483,805
Individually impaired loans, Year One		0	0
Individually impaired loans, Year Two		0	0
Individually impaired loans, Year Three		0	0
Individually impaired loans, Year Four		0	0
Individually impaired loans, Year Five and Earlier		26,012	69,932
Individually impaired loans		26,012	69,932
Total loans, Year One		1,145,229	2,396,303
Total loans, Year Two		2,102,307	117,367
Total loans, Year Three		56,150	585,959
Total loans, Year Four		332,046	169,948
Total loans, Year Five and Earlier		250,014	284,160
Accrued interest receivable		$ 23,200	12,600
Financing Receivable, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]		Accrued interest receivable
Multifamily
Financing Receivable, Credit Quality Indicator [Line Items]
Year One		$ 702,125	697,089
Year Two		722,862	3,131
Year Three		0	47,322
Year Four		0	0
Year Five and Earlier		0	0
Total loans		1,424,987	747,542
Office
Financing Receivable, Credit Quality Indicator [Line Items]
Year One		78,754	784,556
Year Two		676,431	29,636
Year Three		29,650	121,346
Year Four		58,684	59,073
Year Five and Earlier		136,512	73,911
Total loans		980,031	1,068,522
Mixed Use
Financing Receivable, Credit Quality Indicator [Line Items]
Year One		201,777	538,949
Year Two		351,291	84,600
Year Three		26,500	140,926
Year Four		120,300	0
Year Five and Earlier		0	0
Total loans		699,868	764,475
Industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Year One		37,616	41,203
Year Two		96,486	0
Year Three		0	108,469
Year Four		115,545	0
Year Five and Earlier		0	0
Total loans		249,647	149,672
Retail
Financing Receivable, Credit Quality Indicator [Line Items]
Year One		60,089	105,362
Year Two		107,305	0
Year Three		0	89,058
Year Four		12,953	0
Year Five and Earlier		9,126	25,486
Total loans		189,473	219,906
Hospitality
Financing Receivable, Credit Quality Indicator [Line Items]
Year One		0	41,635
Year Two		45,416	0
Year Three		0	43,666
Year Four		13,843	90,132
Year Five and Earlier		78,364	110,890
Total loans		137,623	286,323
Manufactured Housing
Financing Receivable, Credit Quality Indicator [Line Items]
Year One		32,515	117,265
Year Two		82,618	0
Year Three		0	26,404
Year Four		2,921	0
Year Five and Earlier		0	3,941
Total loans		118,054	147,610
Other
Financing Receivable, Credit Quality Indicator [Line Items]
Year One		32,353	26,801
Year Two		19,898	0
Year Three		0	8,768
Year Four		7,800	20,743
Year Five and Earlier		0	0
Total loans		60,051	56,312
Self-Storage
Financing Receivable, Credit Quality Indicator [Line Items]
Year One		0	43,443
Year Two		0	0
Year Three		0	0
Year Four		0	0
Year Five and Earlier		0	0
Total loans		0	43,443
South
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans		850,904	937,125
Northeast
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans		868,199	1,080,652
Midwest
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans		623,599	434,157
West
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans		634,935	530,599
Southwest
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans		$ 882,097	$ 501,272

[1] Includes amounts relating to consolidated variable interest entities. Refer to Note 2 and Note 10.