Partners' Capital, Equity and Incentive Compensation Plans (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Feb. 28, 2019	Sep. 30, 2019	Mar. 31, 2019	Sep. 30, 2019	Jun. 30, 2019
Partners Capital And Distributions [Line Items]
Proceeds From Issuance Of Common Stock				$ 268,392
Class A Common Stock | Underwritten Offering
Partners Capital And Distributions [Line Items]
Shares under underwritten offering	7,762,500
Shares issued	900,000	2,800,000	4,000,000
Common Stock, Capital Shares Reserved for Future Issuance	3,762,500
Share Price	$ 41.50
Proceeds From Issuance Of Common Stock		$ 110,000	$ 159,000
Class A Common Stock | At Market
Partners Capital And Distributions [Line Items]
Maximum value of stock which may be issued					$ 400,000