Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Lease revenues	$ 191,416	$ 217,251	$ 223,388
Rental revenues	199,142	226,350	232,825
Uncollectable accounts written off	14,959	209	5,289
Parking revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	4,207	5,608	5,680
Tenant services
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 3,519	$ 3,491	$ 3,757