Investment Securities, Securities in Continuous Unrealized Loss Position (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018 USD ($) Security	Dec. 31, 2017 USD ($) Security	Jun. 30, 2017 USD ($) Security
Investment Securities [Abstract]
Number of investment securities held | Security	404
Less than 12 months, number of positions | Security	112
12 months or more, number of positions | Security	85
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	$ 234,950	$ 229,523	$ 238,466
Less than 12 months, unrealized loss	5,710	1,127	1,310
12 months or more, fair value	97,047	105,991	0
12 months or more, unrealized loss	2,290	1,050	0
Total, fair value	331,997	335,514	238,466
Total, unrealized loss	8,000	2,177	1,310
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	8,543
Less than 12 months, unrealized loss	79
12 months or more, fair value	0
12 months or more, unrealized loss	0
Total, fair value	8,543
Total, unrealized loss	79	0	0
Obligations of States and Political Subdivisions [Member]
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	8,543
Less than 12 months, unrealized loss	79
12 months or more, fair value	0
12 months or more, unrealized loss	0
Total, fair value	8,543
Total, unrealized loss	$ 79	$ 0	$ 0
Less than 12 months, number of positions | Security	22
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]
Less than 12 months, number of positions | Security	0	0	0
12 months or more, number of positions | Security	0	0	0
US Treasury Notes [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	$ 14,412	$ 94,281	$ 74,423
Less than 12 months, unrealized loss	178	144	272
12 months or more, fair value	29,876	49,883	0
12 months or more, unrealized loss	238	298	0
Total, fair value	44,288	144,164	74,423
Total, unrealized loss	$ 416	442	272
Less than 12 months, number of positions | Security	3
12 months or more, number of positions | Security	2
US Govt SBA [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	$ 5,589	8,379	22,775
Less than 12 months, unrealized loss	68	51	119
12 months or more, fair value	9,023	12,900	0
12 months or more, unrealized loss	120	157	0
Total, fair value	14,612	21,279	22,775
Total, unrealized loss	$ 188	208	119
Less than 12 months, number of positions | Security	29
12 months or more, number of positions | Security	43
Mortgage Backed Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	$ 214,949	126,863	141,268
Less than 12 months, unrealized loss	5,464	932	919
12 months or more, fair value	58,148	43,208	0
12 months or more, unrealized loss	1,932	595	0
Total, fair value	273,097	170,071	141,268
Total, unrealized loss	$ 7,396	$ 1,527	$ 919
Less than 12 months, number of positions | Security	58
12 months or more, number of positions | Security	40