Partners' Capital, Equity and Incentive Compensation Plans (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2017	Jun. 30, 2019	Feb. 28, 2019
Partners Capital And Distributions [Line Items]
Proceeds From Issuance Of Common Stock		$ 268,259	$ 107,549
At Market
Partners Capital And Distributions [Line Items]
Maximum value of stock which may be issued		$ 400,000
Class A Common Stock | Underwritten Offering
Partners Capital And Distributions [Line Items]
Shares under underwritten offering					7,762,500
Common stock, par value					$ 0.01
Shares issued	4,000,000
Shares to be issued on a forward basis (in shares)					3,762,500
Class A Common Stock | At Market
Partners Capital And Distributions [Line Items]
Maximum value of stock which may be issued				$ 400,000