Fair Value Disclosures of Financial Assets and Liabilities - Balances of Assets and Liabilities Measured at Fair Value (Detail) (USD $) | Mar. 31, 2014 | Dec. 31, 2013 |
In Thousands, unless otherwise specified |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | $859,251 | $817,115 |
Total assets measured at fair value on a recurring basis | 859,251 | 817,115 |
Assets Measured at Fair Value on a Nonrecurring Basis | 3,684 | 4,532 |
Total assets measured at fair value on a nonrecurring basis | 50,323 | ' |
Total assets measured at fair value on a nonrecurring basis | ' | 42,911 |
Collateralized Mortgage Obligation ("CMO") [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | 110,083 | 97,557 |
Federal National Mortgage Association ("FNMA") [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | 370,470 | 367,128 |
Federal Home Loan Mortgage Corporation ("FHLMC") [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | 132,899 | 124,495 |
Government National Mortgage Association ("GNMA") [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | 103,141 | 95,592 |
U.S. Government and Agencies [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | 32,083 | 32,158 |
State and Political Subdivisions [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | 110,575 | 100,185 |
Other Real Estate Owned [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Nonrecurring Basis | 3,684 | 4,532 |
Impaired Loans (Collateral Dependent) [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Nonrecurring Basis | 46,639 | 38,379 |
Quoted Prices in Active Markets for Identical Asset (Level 1) [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Total assets measured at fair value on a recurring basis | ' | ' |
Total assets measured at fair value on a nonrecurring basis | ' | ' |
Total assets measured at fair value on a nonrecurring basis | ' | ' |
Quoted Prices in Active Markets for Identical Asset (Level 1) [Member] | Collateralized Mortgage Obligation ("CMO") [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | ' | ' |
Quoted Prices in Active Markets for Identical Asset (Level 1) [Member] | Federal National Mortgage Association ("FNMA") [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | ' | ' |
Quoted Prices in Active Markets for Identical Asset (Level 1) [Member] | Federal Home Loan Mortgage Corporation ("FHLMC") [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | ' | ' |
Quoted Prices in Active Markets for Identical Asset (Level 1) [Member] | Government National Mortgage Association ("GNMA") [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | ' | ' |
Quoted Prices in Active Markets for Identical Asset (Level 1) [Member] | U.S. Government and Agencies [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | ' | ' |
Quoted Prices in Active Markets for Identical Asset (Level 1) [Member] | State and Political Subdivisions [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | ' | ' |
Quoted Prices in Active Markets for Identical Asset (Level 1) [Member] | Other Real Estate Owned [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Nonrecurring Basis | ' | ' |
Quoted Prices in Active Markets for Identical Asset (Level 1) [Member] | Impaired Loans (Collateral Dependent) [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Nonrecurring Basis | ' | ' |
Significant Other Observable Inputs (Level 2) [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Total assets measured at fair value on a recurring basis | 859,251 | 817,115 |
Total assets measured at fair value on a nonrecurring basis | ' | ' |
Total assets measured at fair value on a nonrecurring basis | ' | ' |
Significant Other Observable Inputs (Level 2) [Member] | Collateralized Mortgage Obligation ("CMO") [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | 110,083 | 97,557 |
Significant Other Observable Inputs (Level 2) [Member] | Federal National Mortgage Association ("FNMA") [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | 370,470 | 367,128 |
Significant Other Observable Inputs (Level 2) [Member] | Federal Home Loan Mortgage Corporation ("FHLMC") [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | 132,899 | 124,495 |
Significant Other Observable Inputs (Level 2) [Member] | Government National Mortgage Association ("GNMA") [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | 103,141 | 95,592 |
Significant Other Observable Inputs (Level 2) [Member] | U.S. Government and Agencies [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | 32,083 | 32,158 |
Significant Other Observable Inputs (Level 2) [Member] | State and Political Subdivisions [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | 110,575 | 100,185 |
Significant Other Observable Inputs (Level 2) [Member] | Other Real Estate Owned [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Nonrecurring Basis | ' | ' |
Significant Other Observable Inputs (Level 2) [Member] | Impaired Loans (Collateral Dependent) [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Nonrecurring Basis | ' | ' |
Significant Unobservable Inputs (Level 3) [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Total assets measured at fair value on a recurring basis | ' | ' |
Total assets measured at fair value on a nonrecurring basis | 50,323 | ' |
Total assets measured at fair value on a nonrecurring basis | ' | 42,911 |
Significant Unobservable Inputs (Level 3) [Member] | Collateralized Mortgage Obligation ("CMO") [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | ' | ' |
Significant Unobservable Inputs (Level 3) [Member] | Federal National Mortgage Association ("FNMA") [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | ' | ' |
Significant Unobservable Inputs (Level 3) [Member] | Federal Home Loan Mortgage Corporation ("FHLMC") [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | ' | ' |
Significant Unobservable Inputs (Level 3) [Member] | Government National Mortgage Association ("GNMA") [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | ' | ' |
Significant Unobservable Inputs (Level 3) [Member] | U.S. Government and Agencies [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | ' | ' |
Significant Unobservable Inputs (Level 3) [Member] | State and Political Subdivisions [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Recurring Basis | ' | ' |
Significant Unobservable Inputs (Level 3) [Member] | Other Real Estate Owned [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Nonrecurring Basis | 3,684 | 4,532 |
Significant Unobservable Inputs (Level 3) [Member] | Impaired Loans (Collateral Dependent) [Member] | ' | ' |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ' | ' |
Assets Measured at Fair Value on a Nonrecurring Basis | $46,639 | $38,379 |