Fair Value (Financial Assets and Liabilities at Dates Indicated that were Accounted for or Disclosed at Fair Value) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Residential mortgage loans held for sale (at fair value)	$ 6,656	$ 8,365
Investments available-for-sale (at fair value)	692,107	751,284
Fair Value, Measurements, Recurring | Residential Mortgage Loans Held For Sale
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Residential mortgage loans held for sale (at fair value)	6,656	8,365
Fair Value, Measurements, Recurring | U.S. Government Agencies [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	140,716	139,466
Fair Value, Measurements, Recurring | State and Municipal
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	167,585	165,428
Fair Value, Measurements, Recurring | Mortgage-Backed [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	379,904	442,250
Fair Value, Measurements, Recurring | Corporate Debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	2,002	2,004
Fair Value, Measurements, Recurring | Trust Preferred [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	1,177	1,413
Fair Value, Measurements, Recurring | Marketable Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	723	723
Fair Value, Measurements, Recurring | Interest Rate Swap Agreements
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	1,446	1,608
Other liabilities	(1,446)	(1,608)
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring | Residential Mortgage Loans Held For Sale
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Residential mortgage loans held for sale (at fair value)	6,656	8,365
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring | U.S. Government Agencies [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	140,716	139,466
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring | State and Municipal
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	167,585	165,428
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring | Mortgage-Backed [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	379,904	442,250
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring | Corporate Debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	2,002	2,004
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring | Marketable Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	723	723
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring | Interest Rate Swap Agreements
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	1,446	1,608
Other liabilities	(1,446)	(1,608)
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring | Trust Preferred [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	$ 1,177	$ 1,413