Schedule IV - Mortgage Loans on Real Estate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconcile mortgage loans on real estate
Balance at beginning	$ 4,246,694	$ 2,529,624	$ 2,070,122
CECL Day 1 adjustment	(7,527)
Origination of loan receivables	5,851,517	3,928,467	3,342,099
Purchases of loan receivables	277,170	748,151	386,899
Proceeds from disposition and principal payment of loan receivables	(6,115,265)	(3,455,223)	(3,332,886)
Loans acquired as part of ORM merger transaction		130,449
Net realized gain (loss) on sale of loan receivables	213,740	70,574	57,613
Net unrealized gain (loss) on loan receivables	4,502	1,049	(3,121)
Accretion/amortization of discount, premium and other fees	8,434	14,194	14,474
Loans consolidated as part of RCLT 2019-2 transaction		463,177
Foreign currency gain (loss), net	4,509
Payment of guaranteed loan financing		(177,815)
Transfers to real estate, held for sale	(11,339)	(2,269)	(3,875)
Provision for loan losses	(33,785)	(3,684)	(1,701)
Balance at Ending	4,438,650	4,246,694	2,529,624
Loans, net
Reconcile mortgage loans on real estate
Balance at beginning	4,054,183	2,414,366	1,854,100
CECL Day 1 adjustment	(7,527)
Origination of loan receivables	774,581	1,307,143	934,607
Purchases of loan receivables	277,170	739,002	369,418
Proceeds from disposition and principal payment of loan receivables	(962,404)	(826,702)	(746,162)
Loans acquired as part of ORM merger transaction		130,449
Net realized gain (loss) on sale of loan receivables	(5,069)	(5,700)	(5,454)
Net unrealized gain (loss) on loan receivables	(1,105)	760	(720)
Accretion/amortization of discount, premium and other fees	8,434	14,194	14,474
Loans consolidated as part of RCLT 2019-2 transaction		463,177
Foreign currency gain (loss), net	4,509
Payment of guaranteed loan financing		(177,815)
Transfers	714	1,262	(503)
Transfers to real estate, held for sale	(11,339)	(2,269)	(3,693)
Provision for loan losses	(33,785)	(3,684)	(1,701)
Balance at Ending	4,098,362	4,054,183	2,414,366
Loans, held for sale, at fair value
Reconcile mortgage loans on real estate
Balance at beginning	192,511	115,258	216,022
Origination of loan receivables	5,076,936	2,621,324	2,407,492
Purchases of loan receivables		9,149	17,481
Proceeds from disposition and principal payment of loan receivables	(5,152,861)	(2,628,521)	(2,586,724)
Net realized gain (loss) on sale of loan receivables	218,809	76,274	63,067
Net unrealized gain (loss) on loan receivables	5,607	289	(2,401)
Transfers	(714)	(1,262)	503
Transfers to real estate, held for sale			(182)
Balance at Ending	$ 340,288	$ 192,511	$ 115,258