Debt (Details) (USD $)	3 Months Ended
	Mar. 31, 2015 quarter	Mar. 31, 2014		Dec. 31, 2014
Credit Facilities (Textual)
Borrowings under the Revolver	$ 200,000,000	$ 0	[1]
Proceeds from the subordinated credit agreement with Valero	160,000,000	0	[1]
Capitalized Interest [Abstract]
Capitalized interest	5,000	0
Line of Credit [Member] | Revolving Credit Facility [Member]
Credit Facilities (Textual)
Line of credit facility, maximum borrowing capacity	300,000,000
Line of credit facility, expiration date	Dec. 31, 2018
Number of prior quarterly reporting periods used for subordinated credit agreements' total debt to EBITDA ratio	4
Borrowings under the Revolver	200,000,000	0
Line of credit facility, interest rate, at period end	1.4375%
Line of credit facility, amount outstanding	200,000,000			0
Repayments under the Revolver	0	0
Line of Credit [Member] | Revolving Credit Facility [Member] | Maximum [Member]
Credit Facilities (Textual)
Covenant ratio of total debt to EBITDA per terms of agreement	5.0
Covenant ratio of total debt to EBITDA following certain acquisitions per terms of agreement	5.5
Line of Credit [Member] | Letter of Credit [Member]
Credit Facilities (Textual)
Line of credit facility, amount outstanding	0			0
Subordinated Debt [Member] | Majority Shareholder [Member]
Credit Facilities (Textual)
Number of prior quarterly reporting periods used for subordinated credit agreements' total debt to EBITDA ratio	4
Covenant ratio of total debt to EBITDA per terms of agreement	5.0
Covenant ratio of total debt to EBITDA following certain acquisitions per terms of agreement	5.5
Proceeds from the subordinated credit agreement with Valero	160,000,000
Subordinated credit agreement, expiration date	Mar. 01, 2020
Subordinated credit agreement, rate at period end	1.4219%
Subordinated credit agreement, amount outstanding	$ 160,000,000

[1] Prior period financial information has been retrospectively adjusted for the acquisitions of the Texas Crude Systems Business and the Houston and St. Charles Terminal Services Business from Valero Energy Corporation. See Notes 1 and 3.