Earnings Per Unit (Schedule Of Calculation Of Earnings Per Limited Partner Unit - Basic And Diluted) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Unit [Line Items]
Distributions declared	$ 2,848			$ 11,280			$ 8,520	$ 33,829
Earnings in excess of (less than) distributions	7,458			(1,148)			22,339	(2,740)
Total net income	10,306	$ 10,184	$ 10,369	10,132	$ 10,709	$ 10,248	30,859	31,089
General Partner [Member]
Earnings Per Unit [Line Items]
Distributions declared	57			279			171	836
Earnings in excess of (less than) distributions	149			(76)			446	(215)
Total net income	206	$ 204	$ 207	203	$ 213	$ 205	617	621
Common Units [Member] | Limited Partners [Member]
Earnings Per Unit [Line Items]
Distributions declared	2,791			11,001			8,349	32,993
Earnings in excess of (less than) distributions	7,309			(1,072)			21,893	(2,525)
Total net income	$ 10,100			$ 9,929			$ 30,242	$ 30,468
Weighted-average units outstanding - basic and diluted	23,161			23,138			23,145	23,125
Earnings per limited partner unit - basic and diluted	$ 0.44			$ 0.43			$ 1.31	$ 1.32