Partners' Capital, Mezzanine Equity and Distributions (Preferred Cash Distributions Paid) (Details) - Preferred Unitholders - Class A Convertible Preferred Units - USD ($) $ / shares in Units, $ in Thousands	Feb. 12, 2021	Nov. 13, 2020	Aug. 14, 2020	May 15, 2020	Feb. 14, 2020	Nov. 14, 2019	Aug. 14, 2019	May 15, 2019
Temporary Equity [Line Items]
Date Paid		Nov. 13, 2020	Aug. 14, 2020	May 15, 2020	Feb. 14, 2020	Nov. 14, 2019	Aug. 14, 2019	May 15, 2019
Per Unit Amount (in dollars per unit)		$ 0.7374	$ 0.7374	$ 0.7374	$ 0.7374	$ 0.7374	$ 0.7374	$ 0.2458
Total Amount		$ 18,684	$ 18,684	$ 18,684	$ 18,684	$ 18,684	$ 18,684	$ 6,138
Subsequent Event | Scenario, Forecast
Temporary Equity [Line Items]
Date Paid	Feb. 12, 2021
Per Unit Amount (in dollars per unit)	$ 0.7374
Total Amount	$ 18,684