Disclosures about Fair Value of Assets and Liabilities - Fair Value Measurements of Assets and Liabilities Recognized on a Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value	$ 508,591	$ 482,801
Corporate notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value	733	51
Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value	508,591	482,801
Recurring Basis [Member] | U.S. Treasury and federal agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value	43,134	51,779
Recurring Basis [Member] | State and municipal [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value	177,898	172,905
Recurring Basis [Member] | Federal agency collateralized mortgage obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value	114,706	96,831
Recurring Basis [Member] | Federal agency mortgage-backed pools [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value	170,894	159,204
Recurring Basis [Member] | Private labeled mortgage-backed pools [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value	1,226	2,031
Recurring Basis [Member] | Hedged Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	95,372	81,018
Recurring Basis [Member] | Forward Sale Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	212	858
Recurring Basis [Member] | Interest Rate Swap Agreements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	(2,773)	(7,707)
Recurring Basis [Member] | Commitments to Originate Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	(22)
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | U.S. Treasury and federal agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | State and municipal [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Federal agency collateralized mortgage obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Federal agency mortgage-backed pools [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Private labeled mortgage-backed pools [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Hedged Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Forward Sale Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Interest Rate Swap Agreements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Commitments to Originate Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value	508,591	482,801
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. Treasury and federal agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value	43,134	51,779
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | State and municipal [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value	177,898	172,905
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Federal agency collateralized mortgage obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value	114,706	96,831
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Federal agency mortgage-backed pools [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value	170,894	159,204
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Private labeled mortgage-backed pools [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value	1,226	2,031
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Hedged Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	95,372	81,018
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Forward Sale Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	212	858
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Interest Rate Swap Agreements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	(2,773)	(7,707)
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Commitments to Originate Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	(22)
Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value
Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. Treasury and federal agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value
Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | State and municipal [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value
Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Federal agency collateralized mortgage obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value
Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Federal agency mortgage-backed pools [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value
Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Private labeled mortgage-backed pools [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value
Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Hedged Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities
Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Forward Sale Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities
Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Interest Rate Swap Agreements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities
Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Commitments to Originate Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities
Recurring Basis [Member] | Corporate notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value	733	51
Recurring Basis [Member] | Corporate notes [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value
Recurring Basis [Member] | Corporate notes [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value	733	51
Recurring Basis [Member] | Corporate notes [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total available for sale securities, Fair Value