Partners' Capital, Mezzanine Capital and Distributions (Changes in Redeemable Noncontrolling Interests) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Apr. 14, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Redeemable Noncontrolling Interest, Equity [Roll Forward]
Balance as of December 31, 2020				$ 141,194
Issuance of preferred units, net of issuance costs				103,042
PIK distribution				14,856
Redemption accretion				2,783
Tax distributions				(10,064)
Balance as of September 30, 2021		$ 251,811		251,811
Subsidiary | Alkali Holdings
Redeemable Noncontrolling Interest, Equity [Roll Forward]
PIK distribution		5,900	$ 3,500	14,900	$ 10,200
Redemption accretion		$ 1,200	$ 700	$ 2,800	$ 2,200
Redeemable Noncontrolling Interest [Line Items]
Equity preferred units issued to pay tax distributions (in units)				10,145
Equity preferred units issued (in units)	1,750			95,000