SCHEDULE III - REAL ESTATE ASSETS AND ACCUMULATED DEPRECIATION - Rollforward of Real Estate and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Real estate:
Balance at the beginning of the year	$ 6,255,883	$ 6,334,855	$ 2,292,751
Acquisitions	49,483	262,605	4,145,977
Real estate assumed	12,962	0	0
Real estate acquired through loan receivable foreclosure	0	0	19,096
Improvements	25,451	27,697	6,954
Impairment	(143,655)	(1,576)	(2,211)
Sale of real estate	(322,910)	(351,922)	(133,897)
Foreign currency translation	6,918	(12,639)	10,556
Write-off of fully depreciated assets	(3,549)	(3,137)	(4,371)
Balance at the end of the year	5,880,583	6,255,883	6,334,855
Accumulated depreciation:
Balance at the beginning of the year	(402,338)	(340,423)	(282,812)
Depreciation expense	(163,863)	(174,398)	(101,198)
Impairment	22,070	163	885
Sale of real estate	2,092	108,122	38,914
Foreign currency translation	(723)	1,061	(583)
Write-off of fully depreciated assets	3,549	3,137	4,371
Balance at the end of the year	$ (539,213)	$ (402,338)	$ (340,423)