Summary of Significant Accounting Policies and Procedures and Newly Adopted Accounting Standards - Provision For Impairment (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) property	Dec. 31, 2018 USD ($) property	Dec. 31, 2017 USD ($) property
Provisions for Impairment
Number of properties	6,483
Provisions for impairment | $	$ 40,186	$ 26,269	$ 14,751
Number of impaired properties held for sale	9	1	0
Number of impaired properties held for investment	5	3	2
Number of impaired properties sold	37	40	24
Held for sale
Provisions for Impairment
Number of properties	23