Securities - Securities with Unrealized Losses Aggregated by Investment Category and Length of Time that Individual Securities have been in Continuous Unrealized Loss Position (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	$ 8,178	$ 152,344
Less than 12 Months, Unrealized Loss	(275)	(2,466)
12 Months or More, Fair Value	99,258	121,004
12 Months or More, Unrealized Loss	(2,305)	(4,516)
Total, Fair Value	107,436	273,348
Total, Unrealized Loss	(2,580)	(6,982)
U.S. Government Sponsored Entities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	65,675
Less than 12 Months, Unrealized Loss	0	(640)
12 Months or More, Fair Value	6,398	31,923
12 Months or More, Unrealized Loss	(4)	(488)
Total, Fair Value	6,398	97,598
Total, Unrealized Loss	(4)	(1,128)
States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	271	9,103
Less than 12 Months, Unrealized Loss	(194)	(234)
12 Months or More, Fair Value	0	2,478
12 Months or More, Unrealized Loss	0	(9)
Total, Fair Value	271	11,581
Total, Unrealized Loss	(194)	(243)
Residential and Multi-Family Mortgage [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	7,907	69,631
Less than 12 Months, Unrealized Loss	(81)	(1,562)
12 Months or More, Fair Value	58,084	50,351
12 Months or More, Unrealized Loss	(635)	(1,832)
Total, Fair Value	65,991	119,982
Total, Unrealized Loss	(716)	(3,394)
Corporate Notes and Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	5,027
Less than 12 Months, Unrealized Loss	0	(2)
12 Months or More, Fair Value	7,940	8,144
12 Months or More, Unrealized Loss	(1,463)	(1,269)
Total, Fair Value	7,940	13,171
Total, Unrealized Loss	(1,463)	(1,271)
Pooled SBA [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	2,908
Less than 12 Months, Unrealized Loss	0	(28)
12 Months or More, Fair Value	25,840	27,127
12 Months or More, Unrealized Loss	(179)	(879)
Total, Fair Value	25,840	30,035
Total, Unrealized Loss	(179)	(907)
Other Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Loss	0	0
12 Months or More, Fair Value	996	981
12 Months or More, Unrealized Loss	(24)	(39)
Total, Fair Value	996	981
Total, Unrealized Loss	$ (24)	$ (39)