Partners' Deficit (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands					3 Months Ended						9 Months Ended	12 Months Ended
	Oct. 15, 2020	Aug. 07, 2020	May 08, 2020	Feb. 07, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Dec. 31, 2019
Limited Partners' Capital Account [Line Items]
Partners' Capital Account, Units					23,208,171						23,208,171	23,160,551
Quarterly cash distribution to unitholders		$ 2,800	$ 2,800	$ 11,300	$ 2,842	$ 2,836	$ 11,280	$ 11,280	$ 11,269	$ 11,269
Distribution per unit											$ 0.46
Distribution Made To Limited Partner And General Partner, Threshold In Days After End Of Each Calendar Quarter, Distribution Payment											45 days
Declaration Date						Jul. 16, 2020	Apr. 16, 2020				Oct. 15, 2020	Jan. 16, 2020
Record Date						Jul. 31, 2020	May 01, 2020					Jan. 31, 2020
Payment Date						Aug. 07, 2020	May 08, 2020					Feb. 07, 2020
Quarterly Distribution		$ 0.12	$ 0.12	$ 0.475	$ 0.12	$ 0.12	$ 0.475	$ 0.475	$ 0.475	$ 0.475
Payable Date											Nov. 13, 2020
Close Of Business Date											Nov. 06, 2020
Subsequent Event [Member]
Limited Partners' Capital Account [Line Items]
Quarterly cash distribution declared	$ 2,800
Distribution Made to Limited Partner, Distributions Declared, Per Unit	$ 0.12
Maximum [Member]
Limited Partners' Capital Account [Line Items]
Incentive distribution, percentage of available cash distributed from operating surplus											48.00%
Credit Facility [Member]
Limited Partners' Capital Account [Line Items]
Line of credit terms, maximum per unit quarterly payments											$ 0.12