Summary of Significant Accounting Policies - Earnings per Share (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share Basic And Diluted [Line Items]
Net income attributable to Agree Realty Corporation	$ 36,663	$ 21,280	$ 89,123	$ 67,766
Less: Series A preferred stock dividends	(289)	0	(289)	0
Net Income Attributable to Common Stockholders	36,374	21,280	88,834	67,766
Less: Income attributable to unvested restricted shares	(106)	(69)	(280)	(233)
Net income used in basic and diluted earnings per share	$ 36,268	$ 21,211	$ 88,554	$ 67,533
Weighted average number of common shares outstanding	69,304,906	53,902,541	65,826,126	50,818,154
Less: Unvested restricted stock	(202,406)	(180,585)	(202,406)	(180,585)
Weighted average number of common shares outstanding used in basic earnings per share	69,102,500	53,721,956	65,623,720	50,637,569
Weighted average number of common shares outstanding used in basic earnings per share	69,102,500	53,721,956	65,623,720	50,637,569
Effect of dilutive securities:
Share-based compensation	110,389	85,380	101,931	87,111
Weighted average number of common shares outstanding used in diluted earnings per share	69,591,848	54,555,672	65,952,113	51,151,462
Restricted Stock [Member]
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	9	3,139	200	2,355
Performance Units [Member]
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		6,390		5,887
2019 ATM Forward Equity
Effect of dilutive securities:
Forward equity offering	0	0	0	19,053
2019 ATM Forward Equity | Forward Sale Agreement [Member]
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount				22,820
April 2020 Forward Equity
Effect of dilutive securities:
Forward equity offering	0	725,821	0	390,795
2020 ATM Forward Equity
Effect of dilutive securities:
Forward equity offering	268,011	22,515	178,321	16,934
2020 ATM Forward Equity | Forward Sale Agreement [Member]
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	4,510	0	34,899
2021 ATM Forward Equity
Effect of dilutive securities:
Forward equity offering	110,948	0	48,141	0
2021 ATM Forward Equity | Forward Sale Agreement [Member]
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0		0