Fair Value - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Securities Available For Sale:
Securities available for sale	$ 546,043	$ 685,720
Trading Securities:
Trading securities	4,576	4,505
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Securities Available For Sale:
Securities available for sale	981	1,002
Interest Rate swaps:	0
Trading Securities:
Trading securities	4,522	4,296
Liabilities
Interest rate swaps	0	0
Significant Other Observable Inputs (Level 2) [Member]
Securities Available For Sale:
Securities available for sale	541,649	683,813
Interest Rate swaps:	131
Trading Securities:
Trading securities	54	209
Liabilities
Interest rate swaps	(867)	(946)
Significant Unobservable Inputs (Level 3) [Member]
Securities Available For Sale:
Securities available for sale	3,413	905
Interest Rate swaps:	0
Trading Securities:
Trading securities	0	0
Liabilities
Interest rate swaps	0	0
Fair Value Measurement on Recurring Basis [Member]
Securities Available For Sale:
Securities available for sale	546,043	685,720
Interest Rate swaps:	131
Trading Securities:
Trading securities	4,576	4,505
Liabilities
Interest rate swaps	(867)	(946)
Fair Value Measurement on Recurring Basis [Member] | U.S. Government Sponsored Entities [Member]
Securities Available For Sale:
Securities available for sale	141,751	155,564
Trading Securities:
Trading securities	54	54
Fair Value Measurement on Recurring Basis [Member] | States and Political Subdivisions [Member]
Securities Available For Sale:
Securities available for sale	171,819	181,002
Fair Value Measurement on Recurring Basis [Member] | Residential and Multi-Family Mortgage [Member]
Securities Available For Sale:
Securities available for sale	157,982	265,164
Fair Value Measurement on Recurring Basis [Member] | Corporate Notes and Bonds [Member]
Securities Available For Sale:
Securities available for sale	18,688	19,430
Trading Securities:
Trading securities	130	155
Fair Value Measurement on Recurring Basis [Member] | Pooled Trust Preferred [Member]
Securities Available For Sale:
Securities available for sale	3,413	905
Fair Value Measurement on Recurring Basis [Member] | Pooled SBA [Member]
Securities Available For Sale:
Securities available for sale	51,409	62,653
Fair Value Measurement on Recurring Basis [Member] | Other Equity Securities [Member]
Securities Available For Sale:
Securities available for sale	981	1,002
Fair Value Measurement on Recurring Basis [Member] | Corporate Equity Securities [Member]
Trading Securities:
Trading securities	3,389	3,044
Fair Value Measurement on Recurring Basis [Member] | Mutual Funds [Member]
Trading Securities:
Trading securities	750	999
Fair Value Measurement on Recurring Basis [Member] | Certificates of Deposit [Member]
Trading Securities:
Trading securities	253	253
Fair Value Measurement on Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Securities Available For Sale:
Securities available for sale	981	1,002
Interest Rate swaps:	0
Trading Securities:
Trading securities	4,522	4,451
Liabilities
Interest rate swaps	0	0
Fair Value Measurement on Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | U.S. Government Sponsored Entities [Member]
Securities Available For Sale:
Securities available for sale	0	0
Trading Securities:
Trading securities	0	0
Fair Value Measurement on Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | States and Political Subdivisions [Member]
Securities Available For Sale:
Securities available for sale	0	0
Fair Value Measurement on Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Residential and Multi-Family Mortgage [Member]
Securities Available For Sale:
Securities available for sale	0	0
Fair Value Measurement on Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Corporate Notes and Bonds [Member]
Securities Available For Sale:
Securities available for sale	0	0
Trading Securities:
Trading securities	130	155
Fair Value Measurement on Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pooled Trust Preferred [Member]
Securities Available For Sale:
Securities available for sale	0	0
Fair Value Measurement on Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Pooled SBA [Member]
Securities Available For Sale:
Securities available for sale	0	0
Fair Value Measurement on Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other Equity Securities [Member]
Securities Available For Sale:
Securities available for sale	981	1,002
Fair Value Measurement on Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Corporate Equity Securities [Member]
Trading Securities:
Trading securities	3,389	3,044
Fair Value Measurement on Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Mutual Funds [Member]
Trading Securities:
Trading securities	750	999
Fair Value Measurement on Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Certificates of Deposit [Member]
Trading Securities:
Trading securities	253	253
Fair Value Measurement on Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member]
Securities Available For Sale:
Securities available for sale	541,649	683,813
Interest Rate swaps:	131
Trading Securities:
Trading securities	54	54
Liabilities
Interest rate swaps	(867)	(946)
Fair Value Measurement on Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. Government Sponsored Entities [Member]
Securities Available For Sale:
Securities available for sale	141,751	155,564
Trading Securities:
Trading securities	54	54
Fair Value Measurement on Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | States and Political Subdivisions [Member]
Securities Available For Sale:
Securities available for sale	171,819	181,002
Fair Value Measurement on Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Residential and Multi-Family Mortgage [Member]
Securities Available For Sale:
Securities available for sale	157,982	265,164
Fair Value Measurement on Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Corporate Notes and Bonds [Member]
Securities Available For Sale:
Securities available for sale	18,688	19,430
Trading Securities:
Trading securities	0	0
Fair Value Measurement on Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Pooled Trust Preferred [Member]
Securities Available For Sale:
Securities available for sale	0	0
Fair Value Measurement on Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Pooled SBA [Member]
Securities Available For Sale:
Securities available for sale	51,409	62,653
Fair Value Measurement on Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Other Equity Securities [Member]
Securities Available For Sale:
Securities available for sale	0	0
Fair Value Measurement on Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Corporate Equity Securities [Member]
Trading Securities:
Trading securities	0	0
Fair Value Measurement on Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Mutual Funds [Member]
Trading Securities:
Trading securities	0	0
Fair Value Measurement on Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Certificates of Deposit [Member]
Trading Securities:
Trading securities	0	0
Fair Value Measurement on Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member]
Securities Available For Sale:
Securities available for sale	3,413	905
Interest Rate swaps:	0
Trading Securities:
Trading securities	0	0
Liabilities
Interest rate swaps	0	0
Fair Value Measurement on Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. Government Sponsored Entities [Member]
Securities Available For Sale:
Securities available for sale	0	0
Trading Securities:
Trading securities	0	0
Fair Value Measurement on Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | States and Political Subdivisions [Member]
Securities Available For Sale:
Securities available for sale	0	0
Fair Value Measurement on Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Residential and Multi-Family Mortgage [Member]
Securities Available For Sale:
Securities available for sale	0	0
Fair Value Measurement on Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Corporate Notes and Bonds [Member]
Securities Available For Sale:
Securities available for sale	0	0
Trading Securities:
Trading securities	0	0
Fair Value Measurement on Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Pooled Trust Preferred [Member]
Securities Available For Sale:
Securities available for sale	3,413	905
Fair Value Measurement on Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Pooled SBA [Member]
Securities Available For Sale:
Securities available for sale	0	0
Fair Value Measurement on Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other Equity Securities [Member]
Securities Available For Sale:
Securities available for sale	0	0
Fair Value Measurement on Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Corporate Equity Securities [Member]
Trading Securities:
Trading securities	0	0
Fair Value Measurement on Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Mutual Funds [Member]
Trading Securities:
Trading securities	0	0
Fair Value Measurement on Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Certificates of Deposit [Member]
Trading Securities:
Trading securities	$ 0	$ 0