Impairments (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) property	Jun. 30, 2019 USD ($) property	Jun. 30, 2020 USD ($) property	Jun. 30, 2019 USD ($) property
Provisions for impairment
Provisions for impairment | $	$ 13,869	$ 13,061	$ 18,347	$ 17,733
Number of impaired properties held for sale	7	0	8	0
Number of impaired properties held for investment	11	2	14	2
Number of impaired properties sold	7	12	14	22
COVID-19 impacted properties
Provisions for impairment
Provisions for impairment | $	$ 8,200
Number of impaired properties held for investment	8