Distributions and Net Income Per Limited Partner Unit (Income In Excess Of Distribution) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Incentive Distribution Made to Managing Member or General Partner [Line Items]
Net income attributable to the Partnership	$ 14,955	$ 12,295
Distributions declared	15,666	13,547
Net income in excess of distribution (distribution in excess of net income)	(711)	(1,252)
IDR Holders [Member]
Incentive Distribution Made to Managing Member or General Partner [Line Items]
Net income attributable to the Partnership	0	733
Distributions declared with respect to the incentive distribution rights	0	733
Net income in excess of distribution (distribution in excess of net income)	0	0
Common units [Member]
Incentive Distribution Made to Managing Member or General Partner [Line Items]
Net income attributable to the Partnership	14,955	11,562
Distributions declared	15,666	12,814
Net income in excess of distribution (distribution in excess of net income)	(711)	(1,252)
Cash Distribution [Member] | IDR Holders [Member]
Incentive Distribution Made to Managing Member or General Partner [Line Items]
Distributions declared with respect to the incentive distribution rights	0	733
Cash Distribution [Member] | Common units [Member]
Incentive Distribution Made to Managing Member or General Partner [Line Items]
Distributions declared	$ 15,666	$ 12,814