Note 22 - Quarterly financial Data (Unaudited) - Summarized Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018		Sep. 30, 2018		Jun. 30, 2018		Mar. 31, 2018		Dec. 31, 2019	Dec. 31, 2018
Revenues	$ 91,506	$ 91,756	$ 94,076	$ 93,732	$ 123,524	[1]	$ 133,158	[1]	$ 83,493	[1]	$ 44,660	[1]	$ 371,070	$ 384,835	[1]
Operating income (loss)	7,945	10,962	7,235	8,040	(46,522)	[2]	6,663	[2]	6,830	[2]	5,815	[2]	34,182	(27,214)	[2]
Net income (loss)	$ 4,340	$ 6,959	$ 3,356	$ 3,757	$ (50,682)	[2]	$ 2,408	[2]	$ 1,785	[2]	$ 4,442	[2]	$ 18,412	$ (42,047)	[2]
Basic and diluted net loss per common unit (in dollars per share)	$ (0.05)	$ 0.01	$ (0.07)	$ (0.06)	$ (1.36)		$ (0.09)		$ (0.11)		$ (0.05)		$ (0.17)	$ (1.61)

[1] The increase in revenue during 2018 is due to an increase in volume in the Partnership's crude oil marketing business.

[2] Operating loss and net loss for the fourth quarter and full year 2018 are impacted by asset impairment charges of $52.4 million and $53.1 million, respectively.