Fair Value - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Securities Available For Sale:
Securities available for sale	$ 687,862	$ 685,991
Trading Securities:
Trading securities	4,073	4,127
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Securities Available For Sale:
Securities available for sale	990	985
Trading Securities:
Trading securities	3,867	3,923
Liabilities,
Interest rate swaps	0	0
Significant Other Observable Inputs (Level 2) [Member]
Securities Available For Sale:
Securities available for sale	686,074	684,345
Trading Securities:
Trading securities	206	204
Liabilities,
Interest rate swaps	(1,079)	(1,116)
Significant Unobservable Inputs (Level 3) [Member]
Securities Available For Sale:
Securities available for sale	798	661
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	687,862	685,991
Trading Securities:
Trading securities	4,073	4,127
Fair Value Measurement on Recurring Basis [Member] \| U.S. Treasury [Member]
Securities Available For Sale:
Securities available for sale	0	0
Fair Value Measurement on Recurring Basis [Member] \| U.S. Government Sponsored Entities [Member]
Securities Available For Sale:
Securities available for sale	182,727	181,625
Trading Securities:
Trading securities	54	52
Fair Value Measurement on Recurring Basis [Member] \| States and Political Subdivisions [Member]
Securities Available For Sale:
Securities available for sale	176,268	177,943
Fair Value Measurement on Recurring Basis [Member] \| Residential and Multi-Family Mortgage [Member]
Securities Available For Sale:
Securities available for sale	245,828	242,607
Fair Value Measurement on Recurring Basis [Member] \| Commercial Mortgage [Member]
Securities Available For Sale:
Securities available for sale	225	374
Fair Value Measurement on Recurring Basis [Member] \| Corporate Notes and Bonds [Member]
Securities Available For Sale:
Securities available for sale	14,202	14,075
Trading Securities:
Trading securities	152	152
Fair Value Measurement on Recurring Basis [Member] \| Pooled Trust Preferred [Member]
Securities Available For Sale:
Securities available for sale	798	661
Fair Value Measurement on Recurring Basis [Member] \| Pooled SBA [Member]
Securities Available For Sale:
Securities available for sale	66,824	67,721
Fair Value Measurement on Recurring Basis [Member] \| Other Securities [Member]
Securities Available For Sale:
Securities available for sale	990	985
Fair Value Measurement on Recurring Basis [Member] \| Corporate Equity Securities [Member]
Trading Securities:
Trading securities	2,680	2,705
Fair Value Measurement on Recurring Basis [Member] \| Mutual Funds [Member]
Trading Securities:
Trading securities	933	965
Fair Value Measurement on Recurring Basis [Member] \| Certificates of Deposit [Member]
Trading Securities:
Trading securities	254	253
Fair Value Measurement on Recurring Basis [Member] \| Interest Rate Swaps [Member]
Liabilities,
Interest rate swaps	(1,079)	(1,116)
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	990	985
Trading Securities:
Trading securities	3,867	3,923
Fair Value Measurement on Recurring Basis [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| U.S. Treasury [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] \| 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] \| Commercial 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	0	0
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 Securities [Member]
Securities Available For Sale:
Securities available for sale	990	985
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	2,680	2,705
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	933	965
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	254	253
Fair Value Measurement on Recurring Basis [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Interest Rate Swaps [Member]
Liabilities,
Interest rate swaps	0	0
Fair Value Measurement on Recurring Basis [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Securities Available For Sale:
Securities available for sale	686,074	684,345
Trading Securities:
Trading securities	206	204
Fair Value Measurement on Recurring Basis [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| U.S. Treasury [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] \| U.S. Government Sponsored Entities [Member]
Securities Available For Sale:
Securities available for sale	182,727	181,625
Trading Securities:
Trading securities	54	52
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	176,268	177,943
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	245,828	242,607
Fair Value Measurement on Recurring Basis [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Commercial Mortgage [Member]
Securities Available For Sale:
Securities available for sale	225	374
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	14,202	14,075
Trading Securities:
Trading securities	152	152
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	66,824	67,721
Fair Value Measurement on Recurring Basis [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Other 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 Other Observable Inputs (Level 2) [Member] \| Interest Rate Swaps [Member]
Liabilities,
Interest rate swaps	(1,079)	(1,116)
Fair Value Measurement on Recurring Basis [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Securities Available For Sale:
Securities available for sale	798	661
Trading Securities:
Trading securities	0	0
Fair Value Measurement on Recurring Basis [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| U.S. Treasury [Member]
Securities Available For Sale:
Securities available for sale	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] \| Commercial 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	798	661
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 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
Fair Value Measurement on Recurring Basis [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Interest Rate Swaps [Member]
Liabilities,
Interest rate swaps	$ 0	$ 0