Partners' Capital, Mezzanine Equity and Distributions (Changes in Redeemable Noncontrolling Interests) (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
	Sep. 23, 2019	Dec. 31, 2019	Dec. 31, 2020
Redeemable Noncontrolling Interest, Equity [Roll Forward]
Issuance of Preferred Units	$ 55,000
Issuance costs	(5,600)
Balance as of September 23, 2019			$ 125,133
Issuance of preferred units, net of issuance costs		$ 73,500	9,311
Distribution paid-in-kind		1,750	13,811
Redemption accretion		483	2,302
Tax distributions			(9,363)
Ending balance	$ 49,400	$ 125,133	$ 141,194
Redeemable Noncontrolling Interest, Equity, Preferred Units, Units issued			9,499