Supplemental Cash Flow Information (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Decrease (increase) in current assets:
Receivables from related party	$ (6,318)	$ 0	$ 0
Prepaid expenses and other	(9)	250	70
Increase (decrease) in current liabilities:
Accounts payable	2,403	0	0
Accrued liabilities	158	0	0
Taxes other than income taxes	734	0	0
Deferred revenue from related party	85	0	0
Changes in current assets and current liabilities	(2,947)	250	70
Other Noncash Activities
Increase in property and equipment and asset retirement obligation	0	0	67
Cash Flows Related to Interest and Income Taxes Paid
Interest paid	602	743	865
Income taxes paid	373	403	311
Majority Shareholder [Member]
Receivables from related party:
Debt issuance costs owed to related party	1,071	0	0
Offering costs owed to related party	3,223	0	0
Amounts due from related party	(5,126)	0	0
Transfer (from) to Valero for:
Noncash transfers (from) to Valero	599	1,023	1,551
Other Noncash Activities
Capital expenditures included in accounts payable	(761)	0	0
Increase in property and equipment and asset retirement obligation	0	0	67
Reduction to property and equipment, net due to capital lease obligation modification	913	0	0
Majority Shareholder [Member] | Indemnification Receivable [Member]
Transfer (from) to Valero for:
Noncash transfers (from) to Valero	(85)	0	0
Majority Shareholder [Member] | Property and Equipment [Member]
Transfer (from) to Valero for:
Noncash transfers (from) to Valero	684	0	(1,165)
Majority Shareholder [Member] | Construction-in-progress [Member]
Transfer (from) to Valero for:
Noncash transfers (from) to Valero	$ 0	$ 1,023	$ 2,716