Investment Securities (Maturities) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Held-to-Maturity Securities:
Held-to-maturity securities, Amortized Cost, Within one year	$ 3,702
Held-to-maturity securities, Fair Value, Within one year	3,719
Held-to-maturity securities, Amortized Cost, After 1 through 5 years	4,126
Held-to-maturity securities, Fair Value, After 1 through 5 years	4,224
Held-to-maturity securities, Amortized Cost, After 5 through 10 years	534
Held-to-maturity securities, Fair Value, After 5 through 10 years	536
Held-to-maturity securities, Amortized Cost, Mortgage-backed securities	839
Held-to-maturity securities, Fair Value, Mortgage-backed securities	893
Held-to-maturity securities, Amortized Cost	9,201	$ 11,387
Held-to-maturity securities, Fair Value	9,372	11,637
Available-for-Sale Securities:
Available-for-sale securities, Amortized Cost, Within one year	16,912
Available-for-sale securities, Fair Value, Within one year	17,172
Available-for-sale securities, Amortized Cost, After 1 through 5 years	79,797
Available-for-sale securities, Fair Value, After 1 through 5 years	82,739
Available-for-sale securities, Amortized Cost, After 5 through 10 years	172,873
Available-for-sale securities, Fair Value, After 5 through 10 years	177,968
Available-for-sale securities, Amortized Cost, After 10 years	174,004
Available-for-sale securities, Fair Value, After 10 years	176,965
Available-for-sale securities, Amortized Cost, Mortgage-backed securities	288,011
Available-for-sale securities, Fair Value, Mortgage-backed securities	284,729
Available-for-sale securities, Amortized Cost	731,597
Available-for-sale securities, Fair Value	$ 739,573	$ 815,299