Stockholders' equity - ATM common stock offering program and Forward Equity Sales Agreements (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended			3 Months Ended			9 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jan. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2021	Sep. 30, 2020	Feb. 28, 2021
Class of Stock
Shares of common stock authorized				200,000,000			200,000,000
Net proceeds from issuance of common stock							$ 2,758,545	$ 1,813,573
Forward Equity Sales Entered in January 2021
Class of Stock
Shares of common stock authorized			6,900,000
Net proceeds from issuance of common stock			$ 1,100,000			$ 850,500
Average issue price per share			$ 164.00
Issuances of common stock (in shares)						5,400,000
Common stock available for future issuance (in shares)				1,500,000			1,500,000
Expected net proceeds from issuance of common stock				$ 228,500
Forward Equity Sales Entered in June 2021
Class of Stock
Shares of common stock authorized	8,100,000				8,100,000
Net proceeds from issuance of common stock	$ 1,500,000				$ 870,300
Average issue price per share	$ 184.00				$ 184.00
Issuances of common stock (in shares)					4,900,000
Common stock available for future issuance (in shares)				3,100,000			3,100,000
Expected net proceeds from issuance of common stock				$ 543,400
ATM Common Stock Offering Program, Established February 2021
Class of Stock
Net proceeds from issuance of common stock				$ 492,300		$ 492,300
Average issue price per share		$ 163.26		$ 200.73		$ 163.26	$ 200.73
Issuances of common stock (in shares)				2,500,000		3,100,000
Common stock available for future issuance (in dollars)									$ 1,000,000
ATM Common Stock Offering Program, Established February 2020
Class of Stock
Net proceeds from issuance of common stock		$ 56,200
Issuances of common stock (in shares)		362,000