Partners' Capital And Distributions (Distributions) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010
Partners' Capital And Distributions [Abstract]
Date Paid	May 2012(1)	[1]	February 2012	November 2011	August 2011	May 2011	February 2011
Per Unit Amount	$ 0.4500		$ 0.4400	$ 0.4275	$ 0.4150	$ 0.4075	$ 0.4000
Total Amount	$ 35,759		$ 31,677	$ 30,777	$ 29,878	$ 26,343	$ 25,846

[1] This distribution will be paid on May 15, 2012 to unitholders of record as of May 1, 2012.