Investment Securities, Securities in Continuous Unrealized Loss Position (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($) Security	Dec. 31, 2018 USD ($)	Jun. 30, 2018 USD ($)
Investment Securities, Qualitative Disclosure [Abstract]
Number of investment securities held | Security	572
Less than 12 months, number of positions | Security	20
12 months or more, number of positions | Security	84
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	$ 161,357	$ 180,524	$ 234,950
Less than 12 months, unrealized loss	26	563	5,710
12 months or more, fair value	41,997	255,418	97,047
12 months or more, unrealized loss	229	4,888	2,290
Total, fair value	203,354	435,942	331,997
Total, unrealized loss	255	5,451	8,000
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	0	6,052	8,543
Less than 12 months, unrealized loss	0	23	79
12 months or more, fair value	0	849	0
12 months or more, unrealized loss	0	16	0
Total, fair value	0	6,901	8,543
Total, unrealized loss	$ 0	39	79
Number of HTM investments with gross unrealized losses | Security	0
Obligations of States and Political Subdivisions [Member]
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	$ 0	6,052	8,543
Less than 12 months, unrealized loss	0	23	79
12 months or more, fair value	0	849	0
12 months or more, unrealized loss	0	16	0
Total, fair value	0	6,901	8,543
Total, unrealized loss	$ 0	39	79
Less than 12 months, number of positions | Security	0
12 months or more, number of positions | Security	0
Municipal Bonds [Member]
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Percentage of bank qualified municipal bond portfolio rated	99.00%
Percentage of portfolio not rated	1.00%
Government Agency & Government-Sponsored Entities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Total, unrealized loss	$ 0	0	0
Less than 12 months, number of positions | Security	0
12 months or more, number of positions | Security	0
US Treasury Notes [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	$ 159,966	124,985	14,412
Less than 12 months, unrealized loss	25	7	178
12 months or more, fair value	0	39,529	29,876
12 months or more, unrealized loss	0	151	238
Total, fair value	159,966	164,514	44,288
Total, unrealized loss	$ 25	158	416
Less than 12 months, number of positions | Security	16
12 months or more, number of positions | Security	0
US Govt SBA [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	$ 60	3,250	5,589
Less than 12 months, unrealized loss	0	28	68
12 months or more, fair value	6,750	8,618	9,023
12 months or more, unrealized loss	114	132	120
Total, fair value	6,810	11,868	14,612
Total, unrealized loss	$ 114	160	188
Less than 12 months, number of positions | Security	2
12 months or more, number of positions | Security	55
Mortgage Backed Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	$ 1,331	52,289	214,949
Less than 12 months, unrealized loss	1	528	5,464
12 months or more, fair value	35,247	207,271	58,148
12 months or more, unrealized loss	115	4,605	1,932
Total, fair value	36,578	259,560	273,097
Total, unrealized loss	$ 116	$ 5,133	$ 7,396
Less than 12 months, number of positions | Security	2
12 months or more, number of positions | Security	29