Amortized Cost And Fair Value Of Investment Securities (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Mar. 31, 2012
Investment Securities Available-for-sale
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 263,208		$ 242,167
Gross Unrealized Gains	4,303		4,061
Gross Unrealized (Losses)	(724)		(3,929)
Fair Value	266,787		242,299
Investment Securities Available-for-sale | US Government Sponsored And Federal Agency Obligations
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,444		3,556
Gross Unrealized Gains	60
Gross Unrealized (Losses)			(25)
Fair Value	3,504		3,531
Investment Securities Available-for-sale | Corporate Stock And Bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	152		652
Gross Unrealized Gains	112		50
Gross Unrealized (Losses)			(41)
Fair Value	264		661
Investment Securities Available-for-sale | Non-agency CMOs
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	7,885	[1]	25,067	[1]
Gross Unrealized Gains	15	[1]	163	[1]
Gross Unrealized (Losses)	(351)	[1]	(3,638)	[1]
Fair Value	7,549	[1]	21,592	[1]
Investment Securities Available-for-sale | Government Sponsored Agency Mortgage-Backed Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,975	[1]	3,944	[1]
Gross Unrealized Gains	209	[1]	251	[1]
Fair Value	3,184	[1]	4,195	[1]
Investment Securities Available-for-sale | GNMA Mortgage Backed Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	248,752	[1]	208,948	[1]
Gross Unrealized Gains	3,907	[1]	3,597	[1]
Gross Unrealized (Losses)	(373)	[1]	(225)	[1]
Fair Value	252,286	[1]	212,320	[1]
Held-to-maturity Securities | Government Sponsored Agency Mortgage-Backed Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost			20	[1],[2]
Fair Value			$ 20	[1],[2]

[1] Primarily collateralized by residential mortgages.

[2] Full principal payoff was received on this security in May, 2012.