Provision For Credit Losses Reflected On Consolidated Statements Of Operations (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2013		Mar. 31, 2012		Mar. 31, 2011
Provisions for Doubtful Accounts [Line Items]
Provision for loan losses	$ 7,733		$ 33,887		$ 50,325
Provision for unfunded commitment losses	1,392	[1]	(309)	[1]	873	[1]
Provision for credit losses	$ 9,125		$ 33,578		$ 51,198

[1] The provision for unfunded commitments includes provisions for unfunded commitments to lend and commercial letters of credit.