Investment Securities - Summary of Amortized Cost and Estimated Fair Values of Securities Held to Maturity (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Schedule of Investments [Line Items]
Amortized Cost	$ 40,965,000	$ 43,467,000
Gross Unrealized Gains	1,735,000	2,618,000
Gross Unrealized Losses	4,407,000	3,390,000
Estimated Fair Value	38,293,000	42,695,000
U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies [Member]
Schedule of Investments [Line Items]
Amortized Cost	10,762,000	10,916,000
Gross Unrealized Gains	1,689,000	2,500,000
Gross Unrealized Losses	0	0
Estimated Fair Value	12,451,000	13,416,000
State and Political Subdivisions [Member]
Schedule of Investments [Line Items]
Amortized Cost	10,367,000	12,515,000
Gross Unrealized Gains	37,000	108,000
Gross Unrealized Losses	299,000	0
Estimated Fair Value	10,105,000	12,623,000
Residential Mortgage-Backed Securities, Agency [Member]
Schedule of Investments [Line Items]
Amortized Cost	50,000	61,000
Gross Unrealized Gains	9,000	10,000
Gross Unrealized Losses	0	0
Estimated Fair Value	59,000	71,000
Single Issue Trust Preferred Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	19,766,000	19,750,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	4,108,000	3,390,000
Estimated Fair Value	15,658,000	16,360,000
Other Corporate Securities [Member]
Schedule of Investments [Line Items]
Amortized Cost	20,000	225,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	$ 20,000	$ 225,000