Equity - Private Perpetual Preferred Units (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Preferred Units [Line Items]
Dividends per share (in USD per share)	$ 0	$ 0.105	$ 0.210	$ 0.315
Private Perpetual Preferred Units, Series 2019
Preferred Units [Line Items]
Private perpetual preferred units, issued (in shares)	4,664,038		4,664,038		4,610,383
Private perpetual preferred units, per unit liquidation preference (in USD per share)	$ 13.52		$ 13.52		$ 13.52
Cumulative preferential annual cash distributions (in USD per share)	$ 0.70		$ 0.70
Private Perpetual Preferred Units, Series 2014
Preferred Units [Line Items]
Private perpetual preferred units, issued (in shares)	1,560,360		1,560,360		1,560,360
Private perpetual preferred units issued during period (in shares)			1,560,360
Private perpetual preferred units, per unit liquidation preference (in USD per share)	$ 16.62		$ 16.62		$ 16.62
Dividends per share (in USD per share)			$ 0.60