Loans Receivable, Net - Property Type and Geographic Distribution of Properties Securing Loans in Portfolio (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($) loan	Dec. 31, 2024 USD ($) security_loan	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($) loan	Dec. 31, 2023 USD ($) security_loan	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans	130	130		178	178
Net book value	$ 19,047,518	$ 19,047,518	$ 19,047,518	$ 23,787,012	$ 23,787,012	$ 23,787,012	$ 25,017,880
CECL reserve	(733,936)	(733,936)	(733,936)	(576,936)	(576,936)	(576,936)	(326,137)
Loans receivable, net	18,313,582	18,313,582	18,313,582	23,210,076	23,210,076	23,210,076
Total Loan Exposure	19,920,539	19,920,539	19,920,539	24,971,028	24,971,028	24,971,028
Net Loan Exposure	17,034,303	17,034,303	17,034,303	21,951,988	21,951,988	21,951,988
Principal balance	19,203,126	19,203,126	19,203,126	23,923,719	23,923,719	23,923,719	$ 25,160,343
Total loan exposure including non-consolidated senior interests	817,500	817,500	817,500	1,100,000	1,100,000	1,100,000
Loan participations sold	100,064	100,064	100,064	337,721	337,721	337,721
Cost-recovery proceeds	106,700	106,700	106,700	53,000	53,000	53,000
Asset-specific debt, net
Accounts, Notes, Loans and Financing Receivable [Line Items]
Long-term debt	1,224,841	1,224,841	1,224,841	1,000,210	1,000,210	1,000,210
Junior Loan Participation
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan participations sold	$ 100,064	100,064	$ 100,064	100,924	100,924	100,924
Senior Participations
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan participations sold				$ 236,797	236,797	$ 236,797
Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			100.00%			100.00%
Subtotal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	100			141
Net book value	$ 12,430,396	12,430,396	$ 12,430,396	$ 15,460,479	15,460,479	$ 15,460,479
Total Loan Exposure	13,328,547	13,328,547	13,328,547	16,652,620	16,652,620	16,652,620
Net Loan Exposure	$ 10,537,164	10,537,164	$ 10,537,164	$ 13,951,306	13,951,306	$ 13,951,306
Subtotal | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			62.00%			64.00%
Sunbelt
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	44			65
Net book value	$ 4,520,632	4,520,632	$ 4,520,632	$ 5,658,172	5,658,172	$ 5,658,172
Total Loan Exposure	4,663,498	4,663,498	4,663,498	5,786,395	5,786,395	5,786,395
Net Loan Exposure	$ 4,084,242	4,084,242	$ 4,084,242	$ 5,402,732	5,402,732	$ 5,402,732
Sunbelt | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			24.00%			25.00%
Northeast
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	21			30
Net book value	$ 4,614,582	4,614,582	$ 4,614,582	$ 5,386,940	5,386,940	$ 5,386,940
Total Loan Exposure	4,673,581	4,673,581	4,673,581	5,426,951	5,426,951	5,426,951
Net Loan Exposure	$ 3,452,961	3,452,961	$ 3,452,961	$ 4,340,660	4,340,660	$ 4,340,660
Northeast | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			20.00%			20.00%
West
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	21			31
Net book value	$ 1,865,382	1,865,382	$ 1,865,382	$ 3,088,644	3,088,644	$ 3,088,644
Total Loan Exposure	2,549,329	2,549,329	2,549,329	4,108,074	4,108,074	4,108,074
Net Loan Exposure	$ 1,746,309	1,746,309	$ 1,746,309	$ 2,910,559	2,910,559	$ 2,910,559
West | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			10.00%			13.00%
Midwest
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	10			9
Net book value	$ 997,156	997,156	$ 997,156	$ 944,132	944,132	$ 944,132
Total Loan Exposure	1,006,613	1,006,613	1,006,613	945,222	945,222	945,222
Net Loan Exposure	$ 820,858	820,858	$ 820,858	$ 913,973	913,973	$ 913,973
Midwest | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			5.00%			4.00%
Northwest
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	4			6
Net book value	$ 432,644	432,644	$ 432,644	$ 382,591	382,591	$ 382,591
Total Loan Exposure	435,526	435,526	435,526	385,978	385,978	385,978
Net Loan Exposure	$ 432,794	432,794	$ 432,794	$ 383,382	383,382	$ 383,382
Northwest | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			3.00%			2.00%
Subtotal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	30			37
Net book value	$ 6,617,122	6,617,122	$ 6,617,122	$ 8,326,533	8,326,533	$ 8,326,533
Total Loan Exposure	6,591,992	6,591,992	6,591,992	8,318,408	8,318,408	8,318,408
Net Loan Exposure	$ 6,497,139	6,497,139	$ 6,497,139	$ 8,000,682	8,000,682	$ 8,000,682
Subtotal | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			38.00%			36.00%
United Kingdom
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	16			20
Net book value	$ 2,916,145	2,916,145	$ 2,916,145	$ 3,470,120	3,470,120	$ 3,470,120
Total Loan Exposure	2,877,609	2,877,609	2,877,609	3,439,678	3,439,678	3,439,678
Net Loan Exposure	$ 2,839,096	2,839,096	$ 2,839,096	$ 3,181,489	3,181,489	$ 3,181,489
United Kingdom | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			17.00%			14.00%
Australia
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	3			5
Net book value	$ 920,182	920,182	$ 920,182	$ 1,429,144	1,429,144	$ 1,429,144
Total Loan Exposure	925,106	925,106	925,106	1,437,870	1,437,870	1,437,870
Net Loan Exposure	$ 923,507	923,507	$ 923,507	$ 1,432,146	1,432,146	$ 1,432,146
Australia | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			5.00%			7.00%
Ireland
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	3			3
Net book value	$ 1,050,276	1,050,276	$ 1,050,276	$ 1,191,068	1,191,068	$ 1,191,068
Total Loan Exposure	1,055,131	1,055,131	1,055,131	1,197,337	1,197,337	1,197,337
Net Loan Exposure	$ 1,048,329	1,048,329	$ 1,048,329	$ 1,188,554	1,188,554	$ 1,188,554
Ireland | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			6.00%			5.00%
Spain
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	3			3
Net book value	$ 785,368	785,368	$ 785,368	$ 1,117,790	1,117,790	$ 1,117,790
Total Loan Exposure	786,576	786,576	786,576	1,120,375	1,120,375	1,120,375
Net Loan Exposure	$ 744,287	744,287	$ 744,287	$ 1,078,811	1,078,811	$ 1,078,811
Spain | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			4.00%			5.00%
Sweden
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	1			1
Net book value	$ 429,084	429,084	$ 429,084	$ 474,262	474,262	$ 474,262
Total Loan Exposure	430,416	430,416	430,416	476,718	476,718	476,718
Net Loan Exposure	$ 429,724	429,724	$ 429,724	$ 476,281	476,281	$ 476,281
Sweden | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			2.00%			2.00%
Other Europe
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	3			5
Net book value	$ 455,417	455,417	$ 455,417	$ 644,149	644,149	$ 644,149
Total Loan Exposure	456,102	456,102	456,102	646,430	646,430	646,430
Net Loan Exposure	$ 451,245	451,245	$ 451,245	$ 643,401	643,401	$ 643,401
Other Europe | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			4.00%			3.00%
Other International
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	1
Net book value	$ 60,650	60,650	$ 60,650
Total Loan Exposure	61,052	61,052	61,052
Net Loan Exposure	$ 60,951	60,951	$ 60,951
Other International | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			0.00%
Office
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	41			54
Net book value	$ 7,386,333	7,386,333	$ 7,386,333	$ 9,253,609	9,253,609	$ 9,253,609
Total Loan Exposure	7,740,932	7,740,932	7,740,932	10,072,963	10,072,963	10,072,963
Net Loan Exposure	$ 5,729,418	5,729,418	$ 5,729,418	$ 7,956,472	7,956,472	$ 7,956,472
Office | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			33.00%			36.00%
Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	50			73
Net book value	$ 5,091,767	5,091,767	$ 5,091,767	$ 5,876,128	5,876,128	$ 5,876,128
Total Loan Exposure	5,309,345	5,309,345	5,309,345	5,997,886	5,997,886	5,997,886
Net Loan Exposure	$ 4,934,364	4,934,364	$ 4,934,364	$ 5,756,192	5,756,192	$ 5,756,192
Multifamily | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			29.00%			26.00%
Hospitality
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	16			23
Net book value	$ 2,768,374	2,768,374	$ 2,768,374	$ 4,161,525	4,161,525	$ 4,161,525
Total Loan Exposure	2,812,485	2,812,485	2,812,485	4,194,588	4,194,588	4,194,588
Net Loan Exposure	$ 2,663,349	2,663,349	$ 2,663,349	$ 3,804,091	3,804,091	$ 3,804,091
Hospitality | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			16.00%			17.00%
Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	11			12
Net book value	$ 2,030,627	2,030,627	$ 2,030,627	$ 2,189,808	2,189,808	$ 2,189,808
Total Loan Exposure	2,039,069	2,039,069	2,039,069	2,201,497	2,201,497	2,201,497
Net Loan Exposure	$ 2,000,831	2,000,831	$ 2,000,831	$ 2,190,914	2,190,914	$ 2,190,914
Industrial | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			12.00%			10.00%
Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	5			6
Net book value	$ 555,553	555,553	$ 555,553	$ 814,241	814,241	$ 814,241
Total Loan Exposure	585,221	585,221	585,221	834,825	834,825	834,825
Net Loan Exposure	$ 532,069	532,069	$ 532,069	$ 785,573	785,573	$ 785,573
Retail | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			3.00%			4.00%
Life Sciences / Studio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	3			4
Net book value	$ 342,817	342,817	$ 342,817	$ 385,098	385,098	$ 385,098
Total Loan Exposure	560,564	560,564	560,564	561,517	561,517	561,517
Net Loan Exposure	$ 337,687	337,687	$ 337,687	$ 384,219	384,219	$ 384,219
Life Sciences / Studio | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			2.00%			2.00%
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | loan	4			6
Net book value	$ 872,047	872,047	$ 872,047	$ 1,106,603	1,106,603	$ 1,106,603
Total Loan Exposure	872,923	872,923	872,923	1,107,752	1,107,752	1,107,752
Net Loan Exposure	$ 836,585	$ 836,585	$ 836,585	$ 1,074,527	$ 1,074,527	$ 1,074,527
Other | Loan Exposure Risk | Financing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net Loan Exposure Percentage of Portfolio			5.00%			5.00%