Table - Common Unit Options Activity (Details) (Common Unit Options [Member], USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Common Unit Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	142,550	156,550	156,850	201,950
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 22.04	$ 21.96	$ 21.99	$ 21.93
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	142,550	156,550	156,850
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period		300	6,800
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price		$ 23.73	$ 26.72
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	(14,000)		(38,300)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	$ 21.14		$ 20.84