Related Party Transactions (Details) (ESL Investments, Inc. [Member])	Feb. 13, 2013	Dec. 31, 2012 Letter Agreements, Automotive Manufacturers [Member]	Dec. 31, 2012 Honda [Member]	Dec. 31, 2012 Toyota [Member]	Dec. 31, 2012 Other Automotive Manufacturers [Member]
Related Party Transaction [Line Items]
Related Party, Ownership Percentage by Related Party, Maximum Threshold not Subject to Voting Restrictions		50.00%	50.00%	50.00%	50.00%
Beneficial Ownership, Percentage of Common Stock Outsanding	44.00%
Related Party, Voting Shares, Minimum Threshold Percentage, Treatment of Voting Shares in Excess of Threshold Percentage			50.00%	50.00%
Related Party, Ownership Percentage by Related Party, Agreement Termination, Minimum Threshold				40.00%