Fair Value of Financial Instruments (Assets Measured at Fair Value Recurring) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Recurring Basis
Available-for-sale securities	$ 762,143	$ 784,701
Held-to-maturity securities	45,145	45,853
Quoted Prices in Active Markets for Identical Assets (Level 1)
Recurring Basis
Held-to-maturity securities	0	0
Significant Other Observable Inputs (Level 2)
Recurring Basis
Held-to-maturity securities	45,145	45,853
Significant Unobservable Inputs (Level 3)
Recurring Basis
Held-to-maturity securities	0	0
U.S. government sponsored agencies
Recurring Basis
Available-for-sale securities	1,001	2,966
States and political subdivisions
Recurring Basis
Available-for-sale securities	117,839	114,726
Held-to-maturity securities	4,285	4,221
States and political subdivisions | Quoted Prices in Active Markets for Identical Assets (Level 1)
Recurring Basis
Held-to-maturity securities	0	0
States and political subdivisions | Significant Other Observable Inputs (Level 2)
Recurring Basis
Held-to-maturity securities	4,285	4,221
States and political subdivisions | Significant Unobservable Inputs (Level 3)
Recurring Basis
Held-to-maturity securities	0	0
Residential mortgage-backed securities
Recurring Basis
Available-for-sale securities	607,452	632,293
Held-to-maturity securities	35,205	35,196
Residential mortgage-backed securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Recurring Basis
Held-to-maturity securities	0	0
Residential mortgage-backed securities | Significant Other Observable Inputs (Level 2)
Recurring Basis
Held-to-maturity securities	35,205	35,196
Residential mortgage-backed securities | Significant Unobservable Inputs (Level 3)
Recurring Basis
Held-to-maturity securities	0	0
Commercial mortgage-backed securities
Recurring Basis
Available-for-sale securities	23,283	23,845
Held-to-maturity securities	5,655	6,436
Commercial mortgage-backed securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Recurring Basis
Held-to-maturity securities	0	0
Commercial mortgage-backed securities | Significant Other Observable Inputs (Level 2)
Recurring Basis
Held-to-maturity securities	5,655	6,436
Commercial mortgage-backed securities | Significant Unobservable Inputs (Level 3)
Recurring Basis
Held-to-maturity securities	0	0
Bank-issued trust preferred securities
Recurring Basis
Available-for-sale securities	4,783	4,635
Equity securities
Recurring Basis
Available-for-sale securities	7,785	6,236
Recurring Basis [Member]
Recurring Basis
Available-for-sale securities	762,143	784,701
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Recurring Basis
Available-for-sale securities	7,569	6,024
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2)
Recurring Basis
Available-for-sale securities	754,574	778,677
Recurring Basis [Member] | Significant Unobservable Inputs (Level 3)
Recurring Basis
Available-for-sale securities	0	0
Recurring Basis [Member] | U.S. government sponsored agencies
Recurring Basis
Available-for-sale securities	1,001	2,966
Recurring Basis [Member] | U.S. government sponsored agencies | Quoted Prices in Active Markets for Identical Assets (Level 1)
Recurring Basis
Available-for-sale securities	0	0
Recurring Basis [Member] | U.S. government sponsored agencies | Significant Other Observable Inputs (Level 2)
Recurring Basis
Available-for-sale securities	1,001	2,966
Recurring Basis [Member] | U.S. government sponsored agencies | Significant Unobservable Inputs (Level 3)
Recurring Basis
Available-for-sale securities	0	0
Recurring Basis [Member] | States and political subdivisions
Recurring Basis
Available-for-sale securities	117,839	114,726
Recurring Basis [Member] | States and political subdivisions | Quoted Prices in Active Markets for Identical Assets (Level 1)
Recurring Basis
Available-for-sale securities	0	0
Recurring Basis [Member] | States and political subdivisions | Significant Other Observable Inputs (Level 2)
Recurring Basis
Available-for-sale securities	117,839	114,726
Recurring Basis [Member] | States and political subdivisions | Significant Unobservable Inputs (Level 3)
Recurring Basis
Available-for-sale securities	0	0
Recurring Basis [Member] | Residential mortgage-backed securities
Recurring Basis
Available-for-sale securities	607,452	632,293
Recurring Basis [Member] | Residential mortgage-backed securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Recurring Basis
Available-for-sale securities	0	0
Recurring Basis [Member] | Residential mortgage-backed securities | Significant Other Observable Inputs (Level 2)
Recurring Basis
Available-for-sale securities	607,452	632,293
Recurring Basis [Member] | Residential mortgage-backed securities | Significant Unobservable Inputs (Level 3)
Recurring Basis
Available-for-sale securities	0	0
Recurring Basis [Member] | Commercial mortgage-backed securities
Recurring Basis
Available-for-sale securities	23,283	23,845
Recurring Basis [Member] | Commercial mortgage-backed securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Recurring Basis
Available-for-sale securities	0	0
Recurring Basis [Member] | Commercial mortgage-backed securities | Significant Other Observable Inputs (Level 2)
Recurring Basis
Available-for-sale securities	23,283	23,845
Recurring Basis [Member] | Commercial mortgage-backed securities | Significant Unobservable Inputs (Level 3)
Recurring Basis
Available-for-sale securities	0	0
Recurring Basis [Member] | Bank-issued trust preferred securities
Recurring Basis
Available-for-sale securities	4,783	4,635
Recurring Basis [Member] | Bank-issued trust preferred securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Recurring Basis
Available-for-sale securities	0	0
Recurring Basis [Member] | Bank-issued trust preferred securities | Significant Other Observable Inputs (Level 2)
Recurring Basis
Available-for-sale securities	4,783	4,635
Recurring Basis [Member] | Bank-issued trust preferred securities | Significant Unobservable Inputs (Level 3)
Recurring Basis
Available-for-sale securities	0	0
Recurring Basis [Member] | Equity securities
Recurring Basis
Available-for-sale securities	7,785	6,236
Recurring Basis [Member] | Equity securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Recurring Basis
Available-for-sale securities	7,569	6,024
Recurring Basis [Member] | Equity securities | Significant Other Observable Inputs (Level 2)
Recurring Basis
Available-for-sale securities	216	212
Recurring Basis [Member] | Equity securities | Significant Unobservable Inputs (Level 3)
Recurring Basis
Available-for-sale securities	$ 0	$ 0