Investment Securities Available for Sale with Gross Unrealized Losses Aggregated by Investment Category and Length of Time Individual Investment Securities Have Been in Continuous Position (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014 Investment
Investments, Unrealized Loss Position [Line Items]
Number of investment positions in continuous loss position less than twelve months	68
Number of investment positions in continuous loss position more than twelve months	17
Number of investment positions in continuous loss position	85
Fair value of securities in continuous loss position less than twelve months	$ 55,690
Fair value of securities in continuous loss position more than twelve months	10,099
Fair value of securities in continuous loss position	65,789
Gross unrealized losses of securities in continuous loss position less than twelve months	967
Gross unrealized losses of securities in continuous loss position more than twelve months	559
Gross unrealized losses of securities in continuous loss position	1,526
Agency notes and bonds
Investments, Unrealized Loss Position [Line Items]
Number of investment positions in continuous loss position less than twelve months	20
Fair value of securities in continuous loss position less than twelve months	22,047
Gross unrealized losses of securities in continuous loss position less than twelve months	499
Agency CMO
Investments, Unrealized Loss Position [Line Items]
Number of investment positions in continuous loss position less than twelve months	11
Number of investment positions in continuous loss position more than twelve months	2
Fair value of securities in continuous loss position less than twelve months	9,909
Fair value of securities in continuous loss position more than twelve months	1,742
Gross unrealized losses of securities in continuous loss position less than twelve months	185
Gross unrealized losses of securities in continuous loss position more than twelve months	79
Agency mortgage-backed securities
Investments, Unrealized Loss Position [Line Items]
Number of investment positions in continuous loss position less than twelve months	20
Number of investment positions in continuous loss position more than twelve months	2
Fair value of securities in continuous loss position less than twelve months	15,956
Fair value of securities in continuous loss position more than twelve months	1,747
Gross unrealized losses of securities in continuous loss position less than twelve months	113
Gross unrealized losses of securities in continuous loss position more than twelve months	66
Municipal obligations
Investments, Unrealized Loss Position [Line Items]
Number of investment positions in continuous loss position less than twelve months	16
Number of investment positions in continuous loss position more than twelve months	12
Fair value of securities in continuous loss position less than twelve months	6,220
Fair value of securities in continuous loss position more than twelve months	6,208
Gross unrealized losses of securities in continuous loss position less than twelve months	153
Gross unrealized losses of securities in continuous loss position more than twelve months	400
Mutual fund investment
Investments, Unrealized Loss Position [Line Items]
Number of investment positions in continuous loss position less than twelve months	1
Number of investment positions in continuous loss position more than twelve months	1
Fair value of securities in continuous loss position less than twelve months	1,558
Fair value of securities in continuous loss position more than twelve months	402
Gross unrealized losses of securities in continuous loss position less than twelve months	17
Gross unrealized losses of securities in continuous loss position more than twelve months	$ 14