Securities - Current Fair Value and Associated Unrealized Losses on Investments with Unrealized Losses (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	$ 133,081	$ 51,419
Less than 12 months, Unrealized Losses	(4,454)	(748)
12 months or more, Fair Value	12,937	10,009
12 months or more, Unrealized Losses	(947)	(417)
Total, Fair Value	146,018	61,428
Total, Unrealized Losses	(5,401)	(1,165)
Obligations of states and political subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	29,943	8,443
Less than 12 months, Unrealized Losses	(1,578)	(109)
12 months or more, Fair Value	2,727	166
12 months or more, Unrealized Losses	(255)	(6)
Total, Fair Value	32,670	8,609
Total, Unrealized Losses	(1,833)	(115)
Less than 12 months, Fair Value	23,800	11,154
Less than 12 months, Unrealized Losses	(1,524)	(50)
12 months or more, Fair Value	7,533	0
12 months or more, Unrealized Losses	(1,183)	0
Total, Fair Value	31,333	11,154
Total, Unrealized Losses	(2,707)	(50)
U.S. government and agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	5,446	2,947
Less than 12 months, Unrealized Losses	(147)	(24)
12 months or more, Fair Value	819	0
12 months or more, Unrealized Losses	(168)	0
Total, Fair Value	6,265	2,947
Total, Unrealized Losses	(315)	(24)
Residential mortgage backed securities and collateralized mortgage obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	44,197	14,367
Less than 12 months, Unrealized Losses	(1,214)	(288)
12 months or more, Fair Value	3,271	1,662
12 months or more, Unrealized Losses	(139)	(29)
Total, Fair Value	47,468	16,029
Total, Unrealized Losses	(1,353)	(317)
Corporate securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	32,649	16,036
Less than 12 months, Unrealized Losses	(792)	(85)
12 months or more, Fair Value	2,960	6,762
12 months or more, Unrealized Losses	(96)	(233)
Total, Fair Value	35,609	22,798
Total, Unrealized Losses	(888)	(318)
Commercial mortgage backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	5,543	1,535
Less than 12 months, Unrealized Losses	(205)	(89)
12 months or more, Fair Value	1,437	0
12 months or more, Unrealized Losses	(176)	0
Total, Fair Value	6,980	1,535
Total, Unrealized Losses	(381)	(89)
Other asset backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	15,303	8,091
Less than 12 months, Unrealized Losses	(518)	(153)
12 months or more, Fair Value	1,723	1,419
12 months or more, Unrealized Losses	(113)	(149)
Total, Fair Value	17,026	9,510
Total, Unrealized Losses	$ (631)	$ (302)