Securities, Scheduled Maturities of Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Available-for-sale, amortized cost [Abstract]
Due in one year or less	$ 22,269
Due after one year through five years	67,002
Due after five years through 10 years	202,914
Over 10 years	16,981
Subtotal	309,166
Amortized cost	360,780	$ 383,893
Available-for-sale, fair value [Abstract]
Due in one year or less	22,223
Due after one year through five years	65,330
Due after five years through 10 years	194,006
Over 10 years	16,611
Subtotal	298,170
Fair value	348,476	381,535
Held-to-maturity, amortized cost [Abstract]
Due in one year or less	0
Due after one year through five years	5,249
Due after five years through 10 years	18,337
Over 10 years	9,847
Subtotal	33,433
Mortgage-backed securities	80,611
Amortized cost	114,044	120,121
Held-to-maturity, fair value [Abstract]
Due in one year or less	0
Due after one year through five years	5,141
Due after five years through 10 years	17,268
Over 10 years	9,530
Subtotal	31,939
Mortgage-backed securities	77,721
Fair value	109,660	118,557
Collateralized Mortgage Obligations [Member]
Available-for-sale, amortized cost [Abstract]
Without single maturity date	1,059
Amortized cost	1,059	1,191
Available-for-sale, fair value [Abstract]
Without single maturity date	1,036
Fair value	1,036	1,185
Mortgage-backed Securities [Member]
Available-for-sale, amortized cost [Abstract]
Without single maturity date	50,555
Amortized cost	50,555	33,680
Available-for-sale, fair value [Abstract]
Without single maturity date	49,270
Fair value	49,270	33,334
Held-to-maturity, amortized cost [Abstract]
Amortized cost	80,611	86,630
Held-to-maturity, fair value [Abstract]
Fair value	$ 77,721	$ 85,733