Supplemental Financial Statement Information - Cash flow, etc. (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2021	Mar. 31, 2020
Supplemental Cash Flow Information
Increase (decrease) in accounts payable and accrued liabilities related to additions to real estate assets	$ (345)	$ (966)	$ 1,723	$ 93
Interest paid
Interest payments	$ 576	579	$ 1,691	1,684
Income tax rate
Income tax (provision) benefit		$ 76		$ 85
Income tax benefit rate (as a percent)				23.00%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent				21.00%