Securities (Schedule of Contractual Maturities of Securities) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Available for Sale, Amortized Cost
Available for sale Securities, Amortized Cost	$ 400,665	$ 363,366
Available for Sale, Fair Value
Available for sale Securities, Fair Value, Total	401,837	363,644
Held to Maturity, Amortized Cost
Held to maturity Securities, Amortized Cost	502,123	487,076
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Total	500,917	$ 485,650
Debt Securities
Available for Sale, Amortized Cost
Available for Sale, Amortized Cost, Due in one year or less	1,232
Available for Sale, Amortized Cost, Due after one year to five years	38,912
Available for Sale, Amortized Cost, Due after five to ten years	87,856
Available for Sale, Amortized Cost, Due after ten years	253,499
Available for sale Securities, Amortized Cost	381,499
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	1,239
Available for Sale, Fair Value, Due after one year to five years	39,410
Available for Sale, Fair Value, Due after five to ten years	88,207
Available for Sale, Fair Value, Due after ten years	253,320
Available for sale Securities, Fair Value, Total	382,176
Held to Maturity, Amortized Cost
Held to Maturity, Amortized Cost, Due in one year or less	0
Held to Maturity, Amortized Cost, Due after one year to five years	15,915
Held to Maturity, Amortized Cost, Due after five to ten years	21,090
Held to Maturity, Amortized Cost, Due after ten years	465,118
Held to maturity Securities, Amortized Cost	502,123
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Due in one year or less	0
Held to Maturity, Fair Value, Due after one year to five years	16,092
Held to Maturity, Fair Value, Due after five to ten years	21,643
Held to Maturity, Fair Value, Due after ten years	463,182
Held to Maturity, Fair Value, Total	500,917
Equity securities
Available for Sale, Amortized Cost
Available for Sale, Amortized Cost, Marketable equity securities	19,166
Available for Sale, Fair Value
Available for Sale, Fair Value, Marketable equity securities	19,661
Held to Maturity, Amortized Cost
Held to maturity Securities, Amortized Cost	0
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Total	$ 0