Organization and Basis of Presentation - Additional Information (Detail) ft² in Millions	12 Months Ended
	Dec. 31, 2020 ft² Property
Easterly Government Properties LP [Member]
Organization And Significant Accounting Policies [Line Items]
Outstanding common units of aggregate limited partnership interest owned percentage	88.80%
Wholly Owned Operating Properties [Member]
Organization And Significant Accounting Policies [Line Items]
Number of properties	79
Leased percentage of operating properties	99.00%
Aggregate area of land | ft²	7.3
Wholly Owned Operating Properties [Member] | Government [Member]
Organization And Significant Accounting Policies [Line Items]
Number of properties	77
Wholly Owned Operating Properties [Member] | Private Tenants [Member]
Organization And Significant Accounting Policies [Line Items]
Number of properties	2
Wholly Owned Properties Under Development [Member]
Organization And Significant Accounting Policies [Line Items]
Number of properties	1
Aggregate area of land | ft²	0.2