Concentration (Details)	3 Months Ended
	Mar. 31, 2023 property state	Mar. 31, 2022
Continuing operations
Concentration
Number of wholly owned properties | property	157
Number of states in which acquired properties located | state	30
Annualized rental income, excluding properties classified as discontinued operations | Tenant concentration | U.S. Government, State Governments and Four Other Governments
Concentration
Concentration risk percentage	28.50%	29.00%
Annualized rental income, excluding properties classified as discontinued operations | Tenant concentration | U.S. Government
Concentration
Concentration risk percentage	19.60%	19.40%
Annualized rental income, excluding properties classified as discontinued operations | Geographic concentration | California
Concentration
Concentration risk percentage	11.90%
Annualized rental income, excluding properties classified as discontinued operations | Geographic concentration | Illinois
Concentration
Concentration risk percentage	11.00%
Annualized rental income, excluding properties classified as discontinued operations | Geographic concentration | Virginia
Concentration
Concentration risk percentage	11.00%
Annualized rental income, excluding properties classified as discontinued operations | Geographic concentration | District of Columbia
Concentration
Concentration risk percentage	10.40%
Annualized rental income, excluding properties classified as discontinued operations | Geographic concentration | Georgia
Concentration
Concentration risk percentage	9.10%