Securities - Securities with Unrealized Losses Not Recognized in Income (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
12 Months or less, Fair Value	$ 32,548	$ 92,234
12 Months or less, Unrealized Loss	(172)	(2,905)
More than 12 months, Fair Value	42,238	1,247
More than 12 months, Unrealized Loss	(782)	(125)
Total Fair Value	74,786	93,481
Total Unrealized Loss	(954)	(3,030)
U.S. Treasury Securities and Obligations of U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
12 Months or less, Fair Value	10,540	30,800
12 Months or less, Unrealized Loss	(18)	(764)
More than 12 months, Fair Value	19,198	0
More than 12 months, Unrealized Loss	(204)	0
Total Fair Value	29,738	30,800
Total Unrealized Loss	(222)	(764)
Obligations of States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
12 Months or less, Fair Value	1,467	28,428
12 Months or less, Unrealized Loss	(3)	(1,556)
More than 12 months, Fair Value	8,644	968
More than 12 months, Unrealized Loss	(375)	(121)
Total Fair Value	10,111	29,396
Total Unrealized Loss	(378)	(1,677)
Mortgage-backed Securities in Government Sponsored Entities [Member]
Schedule of Available-for-sale Securities [Line Items]
12 Months or less, Fair Value	20,541	32,557
12 Months or less, Unrealized Loss	(151)	(553)
More than 12 months, Fair Value	14,396	279
More than 12 months, Unrealized Loss	(203)	(4)
Total Fair Value	34,937	32,836
Total Unrealized Loss	(354)	(557)
Equity Securities in Financial Institutions [Member]
Schedule of Available-for-sale Securities [Line Items]
12 Months or less, Fair Value		449
12 Months or less, Unrealized Loss		(32)
More than 12 months, Fair Value		0
More than 12 months, Unrealized Loss		0
Total Fair Value		449
Total Unrealized Loss		$ (32)