Summary of Significant Accounting Policies - Earnings per Share (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share Basic And Diluted [Line Items]
Net income attributable to Agree Realty Corporation	$ 22,347	$ 25,258	$ 52,459	$ 46,486
Less: Income attributable to unvested restricted shares	(71)	(83)	(175)	(164)
Net income used in basic and diluted earnings per share	$ 22,276	$ 25,175	$ 52,284	$ 46,322
Weighted average number of common shares outstanding	65,055,820	52,902,628	64,057,906	49,259,014
Less: Unvested restricted stock	(219,836)	(176,398)	(219,836)	(176,398)
Weighted average number of common shares outstanding used in basic earnings per share	64,835,984	52,726,230	63,838,070	49,082,616
Weighted average number of common shares outstanding used in basic earnings per share	64,835,984	52,726,230	63,838,070	49,082,616
Effect of dilutive securities:
Share-based compensation	98,202	68,294	91,413	74,926
Weighted average number of common shares outstanding used in diluted earnings per share	65,185,604	53,266,740	64,079,697	49,423,546
Restricted Stock [Member]
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,440	7,606	2,743	4,682
Performance Units [Member]
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		7,416		5,635
2019 ATM Forward Equity
Effect of dilutive securities:
Forward equity offering				28,579
2019 ATM Forward Equity | Forward Sale Agreement [Member]
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		11,296		34,230
April 2020 Forward Equity
Effect of dilutive securities:
Forward equity offering	217,943	25,652	133,476	14,144
2020 ATM Forward Equity
Effect of dilutive securities:
Forward equity offering		446,564		223,281
2020 ATM Forward Equity | Forward Sale Agreement [Member]
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	70,769	0	50,093
2021 ATM Forward Equity
Effect of dilutive securities:
Forward equity offering	33,475		16,738
2021 ATM Forward Equity | Forward Sale Agreement [Member]
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0		0