Summary of Significant Accounting Policies - Earnings per Share (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share Basic And Diluted [Line Items]
Net income attributable to Agree Realty Corporation	$ 20,611	$ 15,586	$ 57,522	$ 44,961
Less: Income attributable to unvested restricted shares	(98)	(95)	(283)	(296)
Net income used in basic and diluted earnings per share	$ 20,513	$ 15,491	$ 57,239	$ 44,665
Weighted average number of common shares outstanding	42,034,685	31,969,749	40,194,931	31,342,354
Less: Unvested restricted stock	(202,228)	(210,824)	(202,228)	(210,824)
Weighted average number of common shares outstanding used in basic earnings per share	41,832,457	31,758,925	39,992,703	31,131,530
Weighted average number of common shares outstanding used in basic earnings per share	41,832,457	31,758,925	39,992,703	31,131,530
Effect of dilutive securities: Share-based compensation	109,027	80,211	102,845	71,855
Effect of dilutive securities: forward equity offering	376,558		529,893
Weighted average number of common shares outstanding used in diluted earnings per share	42,318,042	32,287,352	40,625,441	31,471,251
March 2018 Forward Sale [Member]
Earnings Per Share Basic And Diluted [Line Items]
Effect of dilutive securities: forward equity offering		439,761		265,048
September 2018 Forward Sales
Earnings Per Share Basic And Diluted [Line Items]
Effect of dilutive securities: forward equity offering		8,455	359,713	2,818
April 2019 Forward Equity
Earnings Per Share Basic And Diluted [Line Items]
Effect of dilutive securities: forward equity offering	376,558	0	170,180	0

The amount net income (loss) attributable to unvested restricted stocks.

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