Partners' Capital, Equity and Incentive Compensation Plans - Equity Issuances (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2020	May 31, 2020	Dec. 31, 2019
Partners Capital And Distributions [Line Items]
Common stock, par value	$ 0.01	$ 0.01				$ 0.01
Shares under underwritten offering	450,133,000	450,133,000				450,133,000
Common stock issuance proceeds, net of costs		$ 285,480,000	$ 268,392,000
ATM
Partners Capital And Distributions [Line Items]
Percentage used in calculating initial forward sale price per share	100.00%	100.00%
Underwritten Offering | Common stock
Partners Capital And Distributions [Line Items]
Share price (in dollars per share)				$ 64.90
Common stock issuance proceeds, net of costs	$ 269,400,000
Underwritten Offering | Common stock | Maximum
Partners Capital And Distributions [Line Items]
Shares under underwritten offering				4,400,000
Class A Common Stock | Prior ATM Program
Partners Capital And Distributions [Line Items]
Maximum value of stock which may be issued			$ 400,000,000
Common stock, par value			$ 0.01
Class A Common Stock | ATM
Partners Capital And Distributions [Line Items]
Maximum value of stock which may be issued					$ 500,000,000