Guarantees (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Maximum determinable exposure of each type of guarantee and the corresponding liability
Maximum Exposure of Guarantee	$ 30,792	$ 8,325
Carrying Amount of Liability	6,245	7,764
Vehicle Residual Value Guarnatees Operating Lease Programs [Member]
Maximum determinable exposure of each type of guarantee and the corresponding liability
Maximum Exposure of Guarantee	24,544	0
Carrying Amount of Liability	0	0
Vehicle Residual Value Guarantees Finance Lease Programs [Member]
Maximum determinable exposure of each type of guarantee and the corresponding liability
Maximum Exposure of Guarantee	14	805
Carrying Amount of Liability	11	244
Standby letters of credit [Member]
Maximum determinable exposure of each type of guarantee and the corresponding liability
Maximum Exposure of Guarantee	6,234	7,520
Carrying Amount of Liability	$ 6,234	$ 7,520