Statements of Combined Consolidated Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
CASH FLOWS FROM (USED IN) OPERATING ACTIVITIES:
Net income (loss)	$ 55,507	$ 18,499	$ (34,001)
Adjustments to reconcile net income (loss) to net cash from (used in) operating activities:
Depreciation and amortization expenses	13,057	11,277	11,233
Amortization of debt issuance costs	1,147	420	0
Unit-based compensation expense	1,191	479	0
Loss on asset disposals	535	26	830
Changes in current assets:
Receivables - trade	(208)	(2,136)	(775)
Receivables - affiliate	(8,253)	(6,453)	0
Prepayments and other current assets	(375)	(914)	0
Changes in current liabilities:
Accounts payable - trade	1,235	1,461	251
Accounts payable - affiliate	4,277	2,848	(627)
Deferred revenue - affiliate	252	1,775	0
Other current liabilities	7,674	1,564	(1,368)
Changes in other noncurrent assets and liabilities	1,466	(2,341)	2,418
Net cash from (used in) operating activities	77,505	26,505	(22,039)
CASH FLOWS FROM (USED IN) INVESTING ACTIVITIES:
Capital expenditures	(90,610)	(15,021)	(4,789)
Deposit for Northwest Products System acquisition	(40,000)	0	0
Capital expenditure reimbursements by affiliate	5,648	0	0
Proceeds from sale of assets	15	0	0
Net cash used in investing activities	(124,947)	(15,021)	(4,789)
CASH FLOWS FROM (USED IN) FINANCING ACTIVITIES:
Proceeds from debt offering	350,000	0	0
Proceeds from issuance of common units, net of issuance costs	170,725	288,132	0
Distributions to Sponsor related to acquisitions	(375,881)	(283,280)	0
Distributions to general partner related to acquisitions	(42,619)	(50,000)	0
Quarterly distributions to unitholders	(51,386)	(18,146)	0
Quarterly distributions to general partner	(1,665)	(371)	0
Repayments under revolving credit agreement	(118,000)	0	0
Borrowings under revolving credit agreement	68,000	50,000	0
Payments on capital lease	(10)	0	0
Sponsor contributions of equity to the Predecessors	52,457	19,690	26,828
Financing costs	(8,828)	(1,852)	0
Capital contributions by affiliate	5,613	2,669	0
Net cash from financing activities	48,406	6,842	26,828
INCREASE IN CASH AND CASH EQUIVALENTS	964	18,326	0
CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR	18,326	0	0
CASH AND CASH EQUIVALENTS, END OF YEAR	19,290	18,326	0
SUPPLEMENTAL CASH FLOW DISCLOSURE:
Interest paid, net of capitalized interest	$ 1,720	$ 1,165	$ 0