Summary of Significant Accounting Policies - Deferred Leasing and Debt Issuance Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Future amortization of deferred leasing costs, excluding those classified as discontinued operations
Deferred financing fees, net	$ 10,631	$ 12,888
Future amortization of deferred financing fees
2020	1,948
2021	1,934
2022	1,703
2023	407
2024	344
Thereafter	7,361
Continuing Operations
Debt Instrument [Line Items]
Deferred leasing costs, gross	55,716	38,840
Accumulated amortization of deferred leasing costs	15,609	13,168
Future amortization of deferred leasing costs, excluding those classified as discontinued operations
2020	5,949
2021	5,419
2022	4,591
2023	3,973
2024	3,536
Thereafter	16,639
Unsecured Revolving Credit Facility
Future amortization of deferred leasing costs, excluding those classified as discontinued operations
Deferred financing fees, gross	4,125
Accumulated amortization of deferred financing fees	$ 1,059	$ 49