Partners' Capital, Mezzanine Capital and Distributions (Preferred Cash Distributions Paid) (Details) - Preferred Unitholders - Class A Convertible Preferred Stock Units - USD ($) $ / shares in Units, $ in Thousands	May 14, 2021	Feb. 12, 2021	Nov. 13, 2020	Aug. 14, 2020	May 15, 2020
Temporary Equity [Line Items]
Date Paid		Feb. 12, 2021	Nov. 13, 2020	Aug. 14, 2020	May 15, 2020
Per Unit Amount (in dollars per unit)		$ 0.7374	$ 0.7374		$ 0.7374
Total Amount		$ 18,684	$ 18,684	$ 18,684	$ 18,684
Forecast | Subsequent Event
Temporary Equity [Line Items]
Date Paid	May 14, 2021
Per Unit Amount (in dollars per unit)	$ 0.7374
Total Amount	$ 18,684