Schedule IV - Reconciliation of Mortgage Loans on Real Estate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
SEC Schedule, 12-29, Real Estate Companies, Investment in Movement in Mortgage Loans on Real Estate [Roll Forward]
Balance at January 1,	$ 16,572,715	$ 16,164,801	$ 14,191,200
Additions during period:
Loan fundings	12,550,463	1,896,276	6,890,249
Amortization of fees and other items	68,267	56,279	57,415
Deductions during period:
Loan repayments and sales proceeds	(6,733,105)	(1,862,955)	(4,974,881)
Principal charge-offs	(14,427)	0	0
Unrealized (loss) gain on foreign currency translation	(297,894)	340,260	67,376
Deferred fees and other items	(143,002)	(21,946)	(66,558)
Net balance at December 31,	22,003,017	16,572,715	16,164,801
CECL reserve	(124,679)	(173,549)	0
Total Loans, Net	$ 21,878,338	$ 16,399,166	$ 16,164,801