Securities - Schedule of Contractual Maturity of Securities Available for Sale, Excluding Equity Securities (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014
Schedule of Available-for-sale Securities [Line Items]
1 year or less, Amortized Cost	$ 25,007
1 year - 5 years, Amortized Cost	157,048
5 years - 10 years, Amortized Cost	137,169
After 10 years, Amortized Cost	38,033
Total, Amortized Cost	357,257
1 year or less, Fair Value	24,642
1 year - 5 years, Fair Value	159,881
5 years - 10 years, Fair Value	139,246
After 10 years, Fair Value	38,147
Total, Fair Value	361,916
Total debt securities, Amortized Cost	696,949
Total debt securities, Fair Value	698,369
Residential and Multi-Family Mortgage [Member]
Schedule of Available-for-sale Securities [Line Items]
Mortgage & asset backed securities, Amortized Cost	274,168
Mortgage & asset backed securities, Fair Value	271,650
Pooled SBA [Member]
Schedule of Available-for-sale Securities [Line Items]
Mortgage & asset backed securities, Amortized Cost	65,524
Mortgage & asset backed securities, Fair Value	$ 64,803