Organization, Basis of Presentation and Significant Accounting Policies (Details 2) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Basic and diluted shares outstanding
Weighted average common shares - basic (in shares)	140,376,996	138,331,248
Weighted average DownREIT units outstanding (in shares)	7,500	7,500
Effect of dilutive securities (in shares)	393,377	493,453
Weighted average common shares - diluted (in shares)	140,777,873	138,832,201
Calculation of Earnings per Share - basic
Net income attributable to common stockholders	$ 167,971	$ 170,366
Net income allocated to unvested restricted shares	(427)	(501)
Net income attributable to common stockholders, adjusted	$ 167,544	$ 169,865
Weighted average common shares - basic (in shares)	140,376,996	138,331,248
Earnings per common share - basic (in dollars per share)	$ 1.19	$ 1.23
Calculation of Earnings per Share - diluted
Net income attributable to common stockholders	$ 167,971	$ 170,366
Add: noncontrolling interests of DownREIT unitholders in consolidated partnerships, including discontinued operations	12	11
Adjusted net income attributable to common stockholders	$ 167,983	$ 170,377
Weighted average common shares - diluted (in shares)	140,777,873	138,832,201
Earnings per common share - diluted (in dollars per share)	$ 1.19	$ 1.23