Finance Receivables Delinquency (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Mar. 31, 2012
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 31 to 60 Days Past Due	$ 476,887	$ 318,412
Financing Receivable, Recorded Investment, Greater than 60 Days Past Due	169,140	124,561
Financing Receivable, Recorded Investment, Greater than 30 Days Past Due	646,027	442,973
Financing Receivable in Repossesion	32,165	24,896
Financing Receivable, Recorded Investment, Past Due	$ 678,192	$ 467,869
Percent of Contractual Amount Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Percent of Contractual Amount Due 31 Days to 60 days	0.00%	3.20%
Percent of Contractual Amount Due Greater Than 60 Days	0.00%	1.20%
Percent of Contractual Amount Due Greater than 31 days	0.00%	4.40%
Percent of Contractual Amount Due in Repossession	0.00%	0.30%
Percent of Contracutal Amount Due Greater Than 31 Days and in Repossession	0.00%	4.70%