Summary of Significant Accounting Policies - Earnings per Share (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share Basic And Diluted [Line Items]
Net income attributable to Agree Realty Corporation	$ 30,112	$ 21,229
Less: Income attributable to unvested restricted shares	(103)	(81)
Net income used in basic and diluted earnings per share	$ 30,009	$ 21,148
Weighted average number of common shares outstanding	63,048,905	45,615,400
Less: Unvested restricted stock	(220,008)	(179,209)
Weighted average number of common shares outstanding used in basic earnings per share	62,828,897	45,436,191
Weighted average number of common shares outstanding used in basic earnings per share	62,828,897	45,436,191
Effect of dilutive securities:
Share-based compensation	62,454	69,069
Weighted average number of common shares outstanding used in diluted earnings per share	62,940,360	45,565,054
Restricted Stock [Member]
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	6,920	4,719
2019 ATM Forward Equity
Effect of dilutive securities:
Forward equity offering		57,158
2019 ATM Forward Equity | Forward Sale Agreement [Member]
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		57,163
2020 ATM Forward Equity
Effect of dilutive securities:
Forward equity offering	49,009	2,636
2020 ATM Forward Equity | Forward Sale Agreement [Member]
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	3,397	29,418
2021 ATM Forward Equity | Forward Sale Agreement [Member]
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	664