Fair Value And Gross Unrealized Losses (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Mar. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Unrealized Loss Position Less than 12 months	$ 82,822	$ 41,350
Unrealized Loss, Unrealized Loss Position Less than 12 months	(373)	(291)
Fair Value, Unrealized Loss Position 12 months or More	6,674	18,109
Unrealized Loss, Unrealized Loss Position 12 months or More	(351)	(3,638)
Total Fair Value	89,496	59,459
Total Unrealized Loss	(724)	(3,929)
Non-agency CMOs
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Unrealized Loss Position Less than 12 months		77
Fair Value, Unrealized Loss Position 12 months or More	6,674	18,109
Unrealized Loss, Unrealized Loss Position 12 months or More	(351)	(3,638)
Total Fair Value	6,674	18,186
Total Unrealized Loss	(351)	(3,638)
GNMA Mortgage Backed Securities
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Unrealized Loss Position Less than 12 months	82,822	37,631
Unrealized Loss, Unrealized Loss Position Less than 12 months	(373)	(225)
Total Fair Value	82,822	37,631
Total Unrealized Loss	(373)	(225)
US Government Sponsored And Federal Agency Obligations
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Unrealized Loss Position Less than 12 months		3,531
Unrealized Loss, Unrealized Loss Position Less than 12 months		(25)
Total Fair Value		3,531
Total Unrealized Loss		(25)
Corporate Stock And Bonds
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Unrealized Loss Position Less than 12 months		111
Unrealized Loss, Unrealized Loss Position Less than 12 months		(41)
Total Fair Value		111
Total Unrealized Loss		$ (41)