Partners' Capital, Mezzanine Capital and Distributions (Changes in Redeemable Noncontrolling Interests) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Apr. 14, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Redeemable Noncontrolling Interest, Equity [Roll Forward]
Balance as of December 31, 2020				$ 141,194
Issuance of preferred units, net of issuance costs				59,247
PIK distribution				8,955
Redemption accretion				1,602
Tax distributions				(6,351)
Balance as of June 30, 2021		$ 204,647		204,647
Subsidiary | Alkali Holdings
Redeemable Noncontrolling Interest, Equity [Roll Forward]
PIK distribution		4,900	$ 3,400	9,000	$ 6,700
Redemption accretion		$ 900	$ 800	$ 1,600	$ 1,500
Redeemable Noncontrolling Interest [Line Items]
Equity preferred units issued to pay tax distributions (in units)				6,356
Equity preferred units issued (in units)	1,750			54,100