Fair Value of Financial Instruments Recurring basis (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Investments
Total held-to-maturity securities	$ 45,853	$ 48,442
Total available-for-sale securities	784,701	636,880
Recurring Basis
Investments
Total available-for-sale securities	784,701	636,880
U.S. Treasury and government agencies
Investments
Total available-for-sale securities	0	1
U.S. Treasury and government agencies | Recurring Basis
Investments
Total available-for-sale securities	0	1
U.S. government sponsored agencies
Investments
Total available-for-sale securities	2,966	5,950
U.S. government sponsored agencies | Recurring Basis
Investments
Total available-for-sale securities	2,966	5,950
States and political subdivisions
Investments
Total held-to-maturity securities	4,221	4,282
Total available-for-sale securities	114,726	64,743
States and political subdivisions | Recurring Basis
Investments
Total available-for-sale securities	114,726	64,743
Residential mortgage-backed securities
Investments
Total held-to-maturity securities	35,196	36,740
Total available-for-sale securities	632,293	527,291
Residential mortgage-backed securities | Recurring Basis
Investments
Total available-for-sale securities	632,293	527,291
Commercial mortgage-backed securities
Investments
Total held-to-maturity securities	6,436	7,420
Total available-for-sale securities	23,845	27,847
Commercial mortgage-backed securities | Recurring Basis
Investments
Total available-for-sale securities	23,845	27,847
Bank-issued trust preferred securities
Investments
Total available-for-sale securities	4,635	5,645
Bank-issued trust preferred securities | Recurring Basis
Investments
Total available-for-sale securities	4,635	5,645
Equity securities
Investments
Total available-for-sale securities	6,236	5,403
Equity securities | Recurring Basis
Investments
Total available-for-sale securities	6,236	5,403
Quoted Prices in Active Markets for Identical Assets (Level 1)
Investments
Total held-to-maturity securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring Basis
Investments
Total available-for-sale securities	6,024	5,204
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Treasury and government agencies | Recurring Basis
Investments
Total available-for-sale securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. government sponsored agencies | Recurring Basis
Investments
Total available-for-sale securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | States and political subdivisions
Investments
Total held-to-maturity securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | States and political subdivisions | Recurring Basis
Investments
Total available-for-sale securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Residential mortgage-backed securities
Investments
Total held-to-maturity securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Residential mortgage-backed securities | Recurring Basis
Investments
Total available-for-sale securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial mortgage-backed securities
Investments
Total held-to-maturity securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial mortgage-backed securities | Recurring Basis
Investments
Total available-for-sale securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Bank-issued trust preferred securities | Recurring Basis
Investments
Total available-for-sale securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity securities | Recurring Basis
Investments
Total available-for-sale securities	6,024	5,204
Significant Other Observable Inputs (Level 2)
Investments
Total held-to-maturity securities	45,853	48,442
Significant Other Observable Inputs (Level 2) | Recurring Basis
Investments
Total available-for-sale securities	778,677	631,676
Significant Other Observable Inputs (Level 2) | U.S. Treasury and government agencies | Recurring Basis
Investments
Total available-for-sale securities	0	1
Significant Other Observable Inputs (Level 2) | U.S. government sponsored agencies | Recurring Basis
Investments
Total available-for-sale securities	2,966	5,950
Significant Other Observable Inputs (Level 2) | States and political subdivisions
Investments
Total held-to-maturity securities	4,221	4,282
Significant Other Observable Inputs (Level 2) | States and political subdivisions | Recurring Basis
Investments
Total available-for-sale securities	114,726	64,743
Significant Other Observable Inputs (Level 2) | Residential mortgage-backed securities
Investments
Total held-to-maturity securities	35,196	36,740
Significant Other Observable Inputs (Level 2) | Residential mortgage-backed securities | Recurring Basis
Investments
Total available-for-sale securities	632,293	527,291
Significant Other Observable Inputs (Level 2) | Commercial mortgage-backed securities
Investments
Total held-to-maturity securities	6,436	7,420
Significant Other Observable Inputs (Level 2) | Commercial mortgage-backed securities | Recurring Basis
Investments
Total available-for-sale securities	23,845	27,847
Significant Other Observable Inputs (Level 2) | Bank-issued trust preferred securities | Recurring Basis
Investments
Total available-for-sale securities	4,635	5,645
Significant Other Observable Inputs (Level 2) | Equity securities | Recurring Basis
Investments
Total available-for-sale securities	212	199
Significant Unobservable Inputs (Level 3)
Investments
Total held-to-maturity securities	0	0
Significant Unobservable Inputs (Level 3) | Recurring Basis
Investments
Total available-for-sale securities	0	0
Significant Unobservable Inputs (Level 3) | U.S. Treasury and government agencies | Recurring Basis
Investments
Total available-for-sale securities	0	0
Significant Unobservable Inputs (Level 3) | U.S. government sponsored agencies | Recurring Basis
Investments
Total available-for-sale securities	0	0
Significant Unobservable Inputs (Level 3) | States and political subdivisions
Investments
Total held-to-maturity securities	0	0
Significant Unobservable Inputs (Level 3) | States and political subdivisions | Recurring Basis
Investments
Total available-for-sale securities	0	0
Significant Unobservable Inputs (Level 3) | Residential mortgage-backed securities
Investments
Total held-to-maturity securities	0	0
Significant Unobservable Inputs (Level 3) | Residential mortgage-backed securities | Recurring Basis
Investments
Total available-for-sale securities	0	0
Significant Unobservable Inputs (Level 3) | Commercial mortgage-backed securities
Investments
Total held-to-maturity securities	0	0
Significant Unobservable Inputs (Level 3) | Commercial mortgage-backed securities | Recurring Basis
Investments
Total available-for-sale securities	0	0
Significant Unobservable Inputs (Level 3) | Bank-issued trust preferred securities | Recurring Basis
Investments
Total available-for-sale securities	0	0
Significant Unobservable Inputs (Level 3) | Equity securities | Recurring Basis
Investments
Total available-for-sale securities	$ 0	$ 0