Fair Values of Assets and Liabilities Summary of Fair Value Hierarchy for Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Nov. 30, 2005	May 31, 2005
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
CAR revolving credit facility	$ 29,250	$ 28,500
ACC amortizing debt facility	0	125
Amortizing debt facilities	29,408	42,200
Revolving credit facility	4,000	4,000
U.K. credit card accounts revolving credit facility	2,579	3,924
Notes Payable, Related Parties	20,000	20,000
Convertible Debt, Fair Value Disclosures	64,418	64,302
Liabilities carried at fair value
Economic sharing arrangement liability	82	119
Notes payable associated with structured financings, at fair value	32,294	36,511
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
CAR revolving credit facility	0	0
ACC amortizing debt facility	0	0
Amortizing debt facilities	0	0
Revolving credit facility	0	0
U.K. credit card accounts revolving credit facility	0	0
Notes Payable, Related Parties	0	0
5.875% convertible senior notes	0	0
Liabilities carried at fair value
Economic sharing arrangement liability	0	0
Notes payable associated with structured financings, at fair value	0	0
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
CAR revolving credit facility	0	0
ACC amortizing debt facility	0	0
Amortizing debt facilities	0	0
Revolving credit facility	0	0
U.K. credit card accounts revolving credit facility	0	0
Notes Payable, Related Parties	0	0
Convertible Debt, Fair Value Disclosures	38,828	37,662
Liabilities carried at fair value
Economic sharing arrangement liability	0	0
Notes payable associated with structured financings, at fair value	0	0
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
CAR revolving credit facility	29,250	28,500
ACC amortizing debt facility	0	125
Amortizing debt facilities	29,408	42,200
Revolving credit facility	4,000	4,000
U.K. credit card accounts revolving credit facility	2,579	3,924
Notes Payable, Related Parties	20,000	20,000
5.875% convertible senior notes	0	0
Liabilities carried at fair value
Economic sharing arrangement liability	82	119
Notes payable associated with structured financings, at fair value	$ 32,294	$ 36,511
Five Point Eight Seven Five Percent Convertible Senior Notes Due Two Thousand Thirty Five [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			5.875%	5.875%