Sale Of Common Units Under Equity Distribution Agreement (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	Sep. 30, 2015
Sale Of Common Units Under Equity Distribution Agreement
Maximum aggregate offering price of common limited partners units under an equity distribution agreement	$ 250,000,000
Common units issued and sold	764,739	764,739
Net proceeds from issuance of common units	$ 19,600,000	$ 19,605,000	$ 240,972,000
Remaining capacity to issue additional common units under an equity distribution agreement	$ 229,800,000	$ 229,800,000