Securities (Amortized Cost and Fair Value by Contractual Maturities) (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Available-for-sale Securities, Amortized Cost
Available-for-sale, amortized cost	$ 410,275
Available-for-sale Securities, Estimated Fair Value
Available-for-sale securities, estimated fair value	407,446
Held-to-maturity Securities, Amortized Cost
Held-to-maturity, amortized cost	15,721
Held-to-maturity Securities, Estimated Fair Value
Held-to-maturity, estimated fair value	16,379
US Government Agencies Short-term Debt Securities [Member]
Available-for-sale Securities, Amortized Cost
Due in one year or less	50
Due after one through five years	5,086
Available-for-sale Securities, Estimated Fair Value
Due in one year or less	50
Due after one through five years	5,066
Held-to-maturity Securities, Amortized Cost
Due in one year or less	5,000
Held-to-maturity Securities, Estimated Fair Value
Due in one year or less	5,009
Nontaxable Municipal Notes [Member]
Available-for-sale Securities, Amortized Cost
Due in one year or less	723
Due after one through five years	7,587
Due after five through ten years	8,784
Due after ten through fifteen years	29,641
Due after fifteen years	53,346
Available-for-sale Securities, Estimated Fair Value
Due in one year or less	729
Due after one through five years	7,482
Due after five through ten years	8,758
Due after ten through fifteen years	30,146
Due after fifteen years	53,318
Asset-backed Securities [Member]
Available-for-sale Securities, Amortized Cost
Due after five through ten years	3,064
Due after ten through fifteen years	11,557
Due after fifteen years	19,471
Available-for-sale Securities, Estimated Fair Value
Due after five through ten years	3,079
Due after ten through fifteen years	11,410
Due after fifteen years	19,111
Certificates of Deposit [Member]
Available-for-sale Securities, Amortized Cost
Due after one through five years	1,976
Available-for-sale Securities, Estimated Fair Value
Due after one through five years	1,981
Corporate Bond Securities [Member]
Available-for-sale Securities, Amortized Cost
Due after one through five years	4,486
Available-for-sale Securities, Estimated Fair Value
Due after one through five years	4,482
Commercial Mortgage Backed Securities [Member]
Available-for-sale Securities, Amortized Cost
Due after one through five years	60,082
Due after five through ten years	90,107
Due after ten through fifteen years	4,424
Due after fifteen years	108,391
Available-for-sale Securities, Estimated Fair Value
Due after one through five years	59,911
Due after five through ten years	89,165
Due after ten through fifteen years	4,314
Due after fifteen years	107,065
CRA Mutual Fund [Member]
Available-for-sale Securities, Amortized Cost
CRA Mutual fund	1,500
Available-for-sale Securities, Estimated Fair Value
Available-for-sale, estimated fair value	1,379
Municipals [Member]
Held-to-maturity Securities, Amortized Cost
Due after one through five years	1,985
Due after five through ten years	1,606
Due after ten through fifteen years	552
Due after fifteen years	6,578
Held-to-maturity Securities, Estimated Fair Value
Due after one through five years	2,004
Due after five through ten years	1,639
Due after ten through fifteen years	529
Due after fifteen years	$ 7,198