Earnings Per Share - Summary of Basic and Diluted Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share Basic And Diluted [Line Items]
Net income		$ 7,880	$ 1,918
Less: Non-controlling interest in Operating Partnership		(889)	(221)
Net income available to Easterly Government Properties, Inc.		6,991	1,697
Less: Dividends on participating securities		(114)	(57)
Net income available to common stockholders		$ 6,877	$ 1,640
Denominator for basic EPS		82,120,353	74,892,711
Denominator for diluted EPS		82,596,597	75,616,233
Basic EPS		$ 0.08	$ 0.02
Diluted EPS		$ 0.08	$ 0.02
Stock Compensation Plan [Member]
Earnings Per Share Basic And Diluted [Line Items]
Dilutive effect		55,822	58,048
Restricted Common Stock [Member]
Earnings Per Share Basic And Diluted [Line Items]
Dilutive effect	[1]	411,434	471,346
Forward Sales Agreements [Member]
Earnings Per Share Basic And Diluted [Line Items]
Dilutive effect	[2]	8,988	194,128

[1] During the three months ended March 31, 2021 and 2020, there were approximately 122,397 and 43,424 unvested performance-based LTIP units, respectively, that were not included in the computation of diluted earnings per share because to do so would have been antidilutive for the period.

[2] During the three months ended March 31, 2021 and 2020, there were approximately 2,549,697 and 523,397 shares, respectively, of underlying unsettled forward sales transactions that were not included in the computation of diluted earnings per share because to do so would have been antidilutive for the period