Unit Based Awards Schedule of compensation costs relate to unit based plan (Details) (Selling, General and Administrative Expenses [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unit-based compensation expense	$ 208	$ 223	$ 387	$ 479
Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unit-based compensation expense	156	155	284	351
Non-employee Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unit-based compensation expense	$ 52	$ 68	$ 103	$ 128