Note 5 - Common and Preferred Unit Distributions - Distributions Made to Partners (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended													12 Months Ended
		Nov. 30, 2022	Aug. 31, 2022	May 31, 2022	Feb. 28, 2022	Nov. 30, 2021	Aug. 31, 2021	May 31, 2021	Feb. 28, 2021	Nov. 30, 2020	Aug. 31, 2020	Jun. 30, 2020	May 31, 2020	Feb. 29, 2020	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Distributions, common units															$ 34,384	$ 22,645	$ 16,890
Preferred Partner [Member] | Preferred Stock [Member]
Distribution per unit, common units (in dollars per share)		$ 30.00	$ 30.00	$ 30.00	$ 30.00	$ 15.00	$ 15.00	$ 15.00	$ 15.00	$ 15.00	$ 30.00	$ 15.45	$ 15.00	$ 30.00
Distribution, preferred stock		$ 7,500	$ 7,500	$ 7,500	$ 7,500	$ 3,980	$ 3,921	$ 3,864	$ 3,806	$ 3,750	$ 7,500	$ 3,863	$ 3,750	$ 7,500
Distributions, paid-in-kind		$ 0	$ 0	$ 0	$ 0	$ 3,980	$ 3,921	$ 3,864	$ 3,806	$ 3,750	$ 0	$ 0	$ 3,750	$ 0
Preferred Partner [Member] | Preferred Stock [Member] | Distrubutions covering July 1 2020 - September 30, 2021 [Member]
Distribution per unit, common units (in dollars per share)	[1]				$ 78.31
Distribution, preferred stock	[1]				$ 19,579
Distributions, paid-in-kind	[1]				$ 0
Common Unitholders, General Partner [Member]
Distribution per unit, common units (in dollars per share)		$ 0.75	$ 0.75	$ 0.75	$ 0.45	$ 0.45	$ 0.45	$ 0.45	$ 0.45	$ 0.45	$ 0.45	$ 0	$ 0	$ 0.45
Distributions, common units	[2]	$ 9,571	$ 9,571	$ 9,570	$ 5,672	$ 5,672	$ 5,671	$ 5,672	$ 5,630	$ 5,630	$ 5,630	$ 0	$ 0	$ 5,630
Common Unitholders, General Partner [Member] | Distrubutions covering July 1 2020 - September 30, 2021 [Member]
Distribution per unit, common units (in dollars per share)	[1]				$ 0
Distributions, common units	[1],[2]				$ 0

[1] Redemption of preferred units paid in kind plus accrued interest.

[2] Totals include the amount paid to NRP's general partner in accordance with the general partner's 2% general partner interest.