Income Taxes - Schedule of Tax Effect of Temporary Differences Giving Rise to Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Allowance for loan losses	$ 10,763	$ 10,953
Supplemental executive retirement benefit	5,229	4,764
Other-than-temporary impairment of investments	4,655	4,123
Other	2,700	2,816
Unfunded SERP liability	695	981
Deferred compensation	235	240
Share based compensation costs	287	194
State net operating loss carryforward	189
Intangible assets	2,820
Property and equipment	1,198
Unrealized gains/losses on available for sale securities	3,259
Deferred tax assets, Total	32,030	24,071
Net deferred tax asset	31,433	19,263
Other	597
Intangible assets		3,825
Property and equipment		780
Unrealized gains/losses on available for sale securities		203
Deferred tax liabilities, Total	$ 597	$ 4,808