CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues:
Revenue - third parties	$ 465,744	$ 386,731	$ 307,243
Revenue - affiliates	449	762	1,031
Total revenue	466,193	387,493	308,274
Costs and expenses:
Cost of sales (excluding depreciation and amortization expense) - affiliates	202,045	183,160	162,925
Depreciation and amortization	103,711	88,298	67,930
Long-lived asset impairment	5,350	29,560	1,060
Selling, general and administrative - affiliates	61,971	49,889	39,380
Interest expense	37,068	25,167	30,400
Other (income) expense, net	(9,481)	(35)	(392)
Total costs and expenses	400,664	376,039	301,303
Income before income taxes	65,529	11,454	6,971
Provision for income taxes	1,506	945	918
Net income	64,023	10,509	6,053
General partner interest in net income	7,969	4,623	3,005
Common units interest in net income	56,054	5,886	2,723
Subordinated units interest in net income			$ 325
Weighted average common units outstanding:
Basic (in units)	47,651	41,371	31,390
Diluted (in units)	47,667	41,382	31,403
Weighted average subordinated units outstanding:
Basic (in units)			3,747
Diluted (in units)			3,747
Income per common unit:
Basic (in dollars per unit)	$ 1.18	$ 0.14	$ 0.09
Diluted (in dollars per unit)	$ 1.18	$ 0.14	$ 0.09
Income per subordinated unit:
Basic (in dollars per unit)			$ 0.09
Diluted (in dollars per unit)			$ 0.09
Distributions declared and paid per limited partner unit in respective periods (in dollars per unit)	$ 2.0800	$ 2.0000	$ 1.9200