Summary of OREO Valuation Allowance Activity (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2013		Mar. 31, 2012		Mar. 31, 2011
Real Estate [Line Items]
Balance at beginning of period	$ 22,521		$ 19,975		$ 16,630
Provision	26,733	[1]	15,338	[1]	15,125
Sales	(13,245)		(12,792)		(11,780)
Balance at end of period	$ 36,009		$ 22,521		$ 19,975

[1] Includes adjustments to the OREO reserve for probable losses.