SCHEDULE III - REAL ESTATE ASSETS AND ACCUMULATED DEPRECIATION - Rollforward of Real Estate and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Real estate:
Balance at the beginning of the year	$ 6,334,855	$ 2,292,751	$ 2,277,457
Acquisitions	262,605	4,145,977	150,782
Real estate acquired through loan receivable foreclosure	0	19,096	10,100
Improvements	27,697	6,954	1,003
Impairment	(1,576)	(2,211)	(39,058)
Sale of real estate	(351,922)	(133,897)	(107,930)
Foreign currency translation	(12,639)	10,556	4,623
Write-off of fully depreciated assets	(3,137)	(4,371)	(4,226)
Balance at the end of the year	6,255,883	6,334,855	2,292,751
Accumulated depreciation:
Balance at the beginning of the year	(340,423)	(282,812)	(237,841)
Depreciation expense	(174,398)	(101,198)	(64,463)
Impairment	163	885	9,247
Sale of real estate	108,122	38,914	6,023
Foreign currency translation	1,061	(583)	(4)
Write-off of fully depreciated assets	3,137	4,371	4,226
Balance at the end of the year	$ (402,338)	$ (340,423)	$ (282,812)