Employees (Notes)	12 Months Ended
Dec. 31, 2015
Employees [Abstract]
Employees [Text Block]	Employees Workforce A portion of our workforce in the refining segment is represented by the United Steel, Paper and Forestry, Rubber Manufacturing, Energy, Allied Industrial and Service Workers International Union and its Local 202. As of December 31, 2015, 180 operations and maintenance hourly employees and 39 truck drivers at the Tyler refinery were represented by the United Steel, Paper and Forestry, Rubber, Manufacturing, Energy, Allied Industrial and Service Workers International Union and its Local 202. The Tyler operations and maintenance hourly employees are currently covered by a collective bargaining agreement that expires on January 31, 2019. The Tyler truck drivers are currently covered by a collective bargaining agreement that expires March 1, 2018. As of December 31, 2015, 154 operations and maintenance hourly employees at the El Dorado refinery were represented by the International Union of Operating Engineers and its Local 381. These employees are covered by a collective bargaining agreement which expires on August 1, 2017. None of our employees in our marketing or retail segments or in our corporate office are represented by a union. We consider our relations with our employees to be satisfactory. 401(k) Plan We sponsor a voluntary 401(k) Employee Retirement Savings Plan for eligible employees administered by Wells Fargo Bank, N.A. Employees must be at least 21 years of age and have 45 days of service to be eligible to participate in the plan. Employee contributions are matched on a fully-vested basis by us up to a maximum of 6% of eligible compensation. Eligibility for the company matching contribution begins on the first of the month following one year of employment. For the years ended December 31, 2015, 2014 and 2013, the 401(k) plan expense recognized was $5.0 million, $4.2 million, and $3.9 million, respectively.

Employees

Workforce

A portion of our workforce in the refining segment is represented by the United Steel, Paper and Forestry, Rubber Manufacturing, Energy, Allied Industrial and Service Workers International Union and its Local 202. As of December 31, 2015, 180 operations and maintenance hourly employees and 39 truck drivers at the Tyler refinery were represented by the United Steel, Paper and Forestry, Rubber, Manufacturing, Energy, Allied Industrial and Service Workers International Union and its Local 202. The Tyler operations and maintenance hourly employees are currently covered by a collective bargaining agreement that expires on January 31, 2019. The Tyler truck drivers are currently covered by a collective bargaining agreement that expires March 1, 2018. As of December 31, 2015, 154 operations and maintenance hourly employees at the El Dorado refinery were represented by the International Union of Operating Engineers and its Local 381. These employees are covered by a collective bargaining agreement which expires on August 1, 2017. None of our employees in our marketing or retail segments or in our corporate office are represented by a union. We consider our relations with our employees to be satisfactory.

401(k) Plan

We sponsor a voluntary 401(k) Employee Retirement Savings Plan for eligible employees administered by Wells Fargo Bank, N.A. Employees must be at least 21 years of age and have 45 days of service to be eligible to participate in the plan. Employee contributions are matched on a fully-vested basis by us up to a maximum of 6% of eligible compensation. Eligibility for the company matching contribution begins on the first of the month following one year of employment. For the years ended December 31, 2015, 2014 and 2013, the 401(k) plan expense recognized was $5.0 million, $4.2 million, and $3.9 million, respectively.