Securities - Summary of Gross Unrealized Losses and Fair Value of Available for Sale Securities (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity, Gross unrealized losses, Total	$ 1,118
Gross unrealized losses, less than 12 months		99
Fair value, less than 12 months		20,237
Gross unrealized losses, 12 months or more		33
Fair value, 12 months or more		1,020
Gross unrealized losses, Total		132
Fair value, Total		21,257
Gross unrealized losses, less than 12 months	2,028
Fair value, less than 12 months	82,361
Gross unrealized losses, 12 months or more	4
Fair value, 12 months or more	801
Gross unrealized losses, Total	2,032
Fair value, Total	83,162
U.S. Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized losses, less than 12 months	9
Fair value, less than 12 months	996
Gross unrealized losses, 12 months or more
Fair value, 12 months or more
Gross unrealized losses, Total	9
Fair value, Total	996
U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity, Gross unrealized losses, less than 12 months	583
Held-to-maturity, Fair value, less than 12 months	14,586
Held-to-maturity, Gross unrealized losses, 12 months or more
Held-to-maturity, Fair value, 12 months or more
Held-to-maturity, Gross unrealized losses, Total	583
Held-to-maturity, Fair value, Total	14,586
Gross unrealized losses, less than 12 months	590	43
Fair value, less than 12 months	19,408	15,957
Gross unrealized losses, 12 months or more
Fair value, 12 months or more
Gross unrealized losses, Total	590	43
Fair value, Total	19,408	15,957
Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity, Gross unrealized losses, less than 12 months	535
Held-to-maturity, Fair value, less than 12 months	21,103
Held-to-maturity, Gross unrealized losses, 12 months or more
Held-to-maturity, Fair value, 12 months or more
Held-to-maturity, Gross unrealized losses, Total	535
Held-to-maturity, Fair value, Total	21,103
Gross unrealized losses, less than 12 months	175	1
Fair value, less than 12 months	22,096	344
Gross unrealized losses, 12 months or more
Fair value, 12 months or more
Gross unrealized losses, Total	175	1
Fair value, Total	22,096	344
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized losses, less than 12 months		39
Fair value, less than 12 months		1,833
Gross unrealized losses, 12 months or more
Fair value, 12 months or more
Gross unrealized losses, Total		39
Fair value, Total		1,833
States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized losses, less than 12 months	134	12
Fair value, less than 12 months	3,599	1,737
Gross unrealized losses, 12 months or more	2
Fair value, 12 months or more	301
Gross unrealized losses, Total	136	12
Fair value, Total	3,900	1,737
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized losses, less than 12 months	2	4
Fair value, less than 12 months	573	366
Gross unrealized losses, 12 months or more	1	24
Fair value, 12 months or more	499	975
Gross unrealized losses, Total	3	28
Fair value, Total	1,072	1,341
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized losses, less than 12 months
Fair value, less than 12 months
Gross unrealized losses, 12 months or more	1	9
Fair value, 12 months or more	1	45
Gross unrealized losses, Total	1	9
Fair value, Total	$ 1	$ 45