Schedule III - Reconciliation of Real Estate Owned (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance as of January 1,	$ 4,692,754	$ 4,785,927	$ 5,499,506
Purchases and additions to investment property	133,259	114,050	272,145
Sale and write-offs of investment property	(111,557)	(203,766)	(829,170)
Property held for sale	0	0	(2,791)
Provision for asset impairment	(34,692)	(3,457)	(153,763)
Balance as of December 31,	$ 4,679,764	$ 4,692,754	$ 4,785,927