Credit Facilities Line of Credit Facilities (Details) (USD $)	Sep. 30, 2012	Dec. 31, 2011
Line of Credit Facility [Line Items]
Line of Credit Facilty - Canada Lease Warehouse Canadian Dollars New	$ 800,000,000
Amount of Cash Collected on Finance Receivables Pledged Excluded from Restricted Cash Pledged	31,800,000
U.S. Dollar [Member]
Line of Credit Facility [Line Items]
Line of Credit Facilty -Syndicated warehouse facility	2,500,000,000
Line of Credit Facilty - U.S. Lease Warehouse Facility	600,000,000
Line of Credit Facility - Canada Lease Warehouse Facility	813,049,000
Line of Credit Facility - Parent Company Revolving Credit Facility	300,000,000
U.S. Dollar [Member] | Line of Credit Facility Advances Outstanding [Member]
Line of Credit Facility [Line Items]
Line of Credit Facilty -Syndicated warehouse facility		621,257,000
Line of Credit Facilty - U.S. Lease Warehouse Facility
Line of Credit Facility - Canada Lease Warehouse Facility	374,496,000	181,314,000
Line of Credit Facility - Parent Company Revolving Credit Facility
Line of Credit Facility - Medium-term note facility	182,450,000	293,528,000
Credit Facility Totals	556,946,000	1,099,391,000
U.S. Dollar [Member] | Line of Credit Facility Assets Pledged [Member]
Line of Credit Facility [Line Items]
Line of Credit Facilty -Syndicated warehouse facility
Line of Credit Facilty - U.S. Lease Warehouse Facility
Line of Credit Facility - Canada Lease Warehouse Facility	584,185,000
Line of Credit Facility - Parent Company Revolving Credit Facility
Line of Credit Facility - Medium-term note facility	200,584,000
Credit Facility Totals	784,769,000
U.S. Dollar [Member] | Line of Credit Faciltiy Restricted Cash Pledged [Member]
Line of Credit Facility [Line Items]
Line of Credit Facilty -Syndicated warehouse facility	300,000
Line of Credit Facilty - U.S. Lease Warehouse Facility
Line of Credit Facility - Canada Lease Warehouse Facility	2,759,000
Line of Credit Facility - Parent Company Revolving Credit Facility
Line of Credit Facility - Medium-term note facility	83,683,000
Credit Facility Totals	86,742,000
Canada, Dollar [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility - Canada Lease Warehouse Canadian Dollar	600,000,000
Canada, Dollar [Member] | Line of Credit Facility Advances Outstanding [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility - Canada Lease Warehouse Facility	368,500,000
Canada, Dollar [Member] | Line of Credit Facility Assets Pledged [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility - Canada Lease Warehouse Facility	574,800,000
Canada, Dollar [Member] | Line of Credit Faciltiy Restricted Cash Pledged [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility - Canada Lease Warehouse Facility	$ 2,700,000