Fair Value (Financial Assets and Liabilities at Dates Indicated that Were Accounted for or Disclosed at Fair Value) (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Residential mortgage loans held for sale (at fair value)	$ 19,445	$ 10,512
Investments available-for-sale (at fair value)	625,819	672,209
Marketable Equity Securities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	723	723
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)	19,445	10,512
Fair Value, Measurements, Recurring | U.S. Government Agencies
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	137,980	141,679
Fair Value, Measurements, Recurring | State and municipal
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	161,953	167,052
Fair Value, Measurements, Recurring | Mortgage-Backed
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	324,145	361,519
Fair Value, Measurements, Recurring | Trust Preferred
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	1,018	1,236
Fair Value, Measurements, Recurring | Marketable Equity Securities
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	1,390	1,501
Other liabilities	(1,390)	(1,501)
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | 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)	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Government Agencies
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | State and municipal
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Mortgage-Backed
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Trust Preferred
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Marketable Equity Securities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Interest Rate Swap Agreements
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Other assets	0	0
Other liabilities	0	0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | 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)	19,445	10,512
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | U.S. Government Agencies
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	137,980	141,679
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | State and municipal
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	161,953	167,052
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Mortgage-Backed
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	324,145	361,519
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Trust Preferred
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	0	0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Marketable Equity Securities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	723	723
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Interest Rate Swap Agreements
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Other assets	1,390	1,501
Other liabilities	(1,390)	(1,501)
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | 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)	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | U.S. Government Agencies
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | State and municipal
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Mortgage-Backed
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Trust Preferred
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	1,018	1,236
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Marketable Equity Securities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments available-for-sale (at fair value)	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Interest Rate Swap Agreements
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Other assets	0	0
Other liabilities	$ 0	$ 0