Quarterly Financial Data (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended									12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011		Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 68,324	$ 49,268	[1]	$ 50,940	$ 45,017	$ 49,369	$ 46,549	$ 45,483	$ 40,696	$ 213,549	$ 182,097	$ 146,561
Operating income	38,911	22,204	[1]	27,288	23,218	26,230	24,172	22,484	17,863	111,621	90,749	68,258
Income before income taxes	29,766	14,037	[1]	19,031	15,397	18,553	16,335	13,481	10,796	78,231	59,165	46,254
Net income	29,701	14,114	[1]	19,013	15,169	18,473	16,259	13,435	10,702	77,997	58,869	66,014
Limited partners’ interest in net income	$ 24,296	$ 10,159	[1]	$ 15,166	$ 11,607	$ 15,048	$ 13,087	$ 10,526	$ 8,056	$ 61,228	$ 46,717	$ 58,067
Limited partners' per unit interest in net income - basic and diluted	$ 0.97	$ 0.46	[1]	$ 0.69	$ 0.53	$ 0.68	$ 0.59	$ 0.48	$ 0.36	$ 2.68	$ 2.12	$ 3.18
Distributions per limited partner unit	$ 0.885	$ 0.875	[1]	$ 0.865	$ 0.855	$ 0.845	$ 0.835	$ 0.825	$ 0.815	$ 3.48	$ 3.32

[1] As a result of our November 9, 2011 tankage and terminal asset acquisition from HFC (see Note 3), we have retrospectively adjusted our third quarter of 2011 operating costs and expenses to include expenses incurred by HFC prior to our acquisition. Therefore, summarized quarterly financial data for the third quarter of the year ended December 31, 2011 does not agree to amounts previously reported.