Securities (Schedule of Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Securities Available-for-Sale: Amortized cost
Due in one year or less	$ 2,814
Due after one year through five years	20,970
Due after five years through ten years	80,105
Due after ten years	167,246
Amortized Cost	752,327	$ 743,642
Securities Available-for-Sale: Fair Value
Due in one year or less	2,835
Due after one year through five years	21,520
Due after five years through ten years	81,462
Due after ten years	166,936
Total Fair Value	737,604	740,641
MBS/CMO - Residential
Securities Available-for-Sale: Amortized cost
Amortized cost, MBS/CMO-Residential	481,192
Amortized Cost	481,192	476,205
Securities Available-for-Sale: Fair Value
Fair value, MBS/CMO Residential	464,851
Total Fair Value	$ 464,851	$ 467,332