Other Assets (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Other Assets [Abstract]
Product prepayments	$ 1,550		$ 2,396
Other prepaid expenses	13,593		14,085
Margin deposits	1,850		596
Derivative assets	0		162
Other	1,523	[1]	11,157	[1]
Total other current assets	$ 18,516		$ 28,396

[1] The change in other from the prior year is primarily due to assets held for sale related to SemStream Arizona which were sold in December 2012. See Note 6 for additional information related to the disposal.