Investment Securities, Analysis of Gross Unrealized Losses (Details) $ in Thousands	Dec. 31, 2018 USD ($) Security	Dec. 31, 2017 USD ($)
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	$ 74,186	$ 117,729
Less than 12 months, unrealized losses	(237)	(1,312)
12 months or more, fair value	187,203	141,518
12 Months or more, unrealized losses	(5,653)	(3,205)
Total fair value	261,389	259,247
Total unrealized losses	$ (5,890)	(4,517)
Investment securities in unrealized loss position less than 12 months | Security	64
Investment securities in unrealized loss position more than 12 months | Security	186
Investment securities pledged as collateral	$ 36,781	32,399
U.S. Treasury Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	37,805	10,004
Less than 12 months, unrealized losses	(67)	(2)
12 months or more, fair value	5,951	8,460
12 Months or more, unrealized losses	(90)	(123)
Total fair value	43,756	18,464
Total unrealized losses	(157)	(125)
Securities of U.S. Government Agencies and Corporations [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	16,959	6,049
Less than 12 months, unrealized losses	(39)	(50)
12 months or more, fair value	13,540	15,060
12 Months or more, unrealized losses	(189)	(194)
Total fair value	30,499	21,109
Total unrealized losses	(228)	(244)
Obligations of States and Political Subdivisions [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	847	7,677
Less than 12 months, unrealized losses	(2)	(34)
12 months or more, fair value	9,134	7,116
12 Months or more, unrealized losses	(121)	(112)
Total fair value	9,981	14,793
Total unrealized losses	(123)	(146)
Collateralized Mortgage Obligations [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	2,217	31,679
Less than 12 months, unrealized losses	(6)	(576)
12 months or more, fair value	53,217	34,404
12 Months or more, unrealized losses	(1,844)	(1,065)
Total fair value	55,434	66,083
Total unrealized losses	(1,850)	(1,641)
Mortgage-backed Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	16,358	62,320
Less than 12 months, unrealized losses	(123)	(650)
12 months or more, fair value	105,361	76,478
12 Months or more, unrealized losses	(3,409)	(1,711)
Total fair value	121,719	138,798
Total unrealized losses	$ (3,532)	$ (2,361)