Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Thousands	Apr. 10, 2019	Sep. 30, 2004
Commitments And Contingencies [Line Items]
The term of a former ground lease		99 years
Number of years of monitoring and reporting costs of an individual site		7 years
Subsequent Event [Member]
Commitments And Contingencies [Line Items]
Net monitoring and reporting costs received	$ 180