Investment Securities - Available-for-Sale Securities, Continuous Unrealized Loss Position, Fair Value (Details) $ in Thousands	Dec. 31, 2019 USD ($) security	Dec. 31, 2018 USD ($) security
Less than 12 months
Number of securities | security	77	119
Fair Value	$ 45,813	$ 45,666
Unrealized Loss	$ (255)	$ (211)
Percent of Unrealized Loss	0.56%	0.46%
12 months or more
Number of securities | security	27	358
Fair Value	$ 21,549	$ 159,235
Unrealized Loss	$ (75)	$ (2,925)
Percent of Unrealized Loss	0.35%	1.84%
Total
Number of securities | security	104	477
Fair Value	$ 67,362	$ 204,901
Unrealized Loss	$ (330)	$ (3,136)
Percent of Unrealized Loss	0.49%	1.53%
US Treasury Securities [Member]
Less than 12 months
Number of securities | security	11	6
Fair Value	$ 27,932	$ 14,644
Unrealized Loss	$ (136)	$ (49)
Percent of Unrealized Loss	0.49%	0.33%
12 months or more
Number of securities | security	1	19
Fair Value	$ 2,495	$ 46,443
Unrealized Loss	$ (1)	$ (759)
Percent of Unrealized Loss	0.04%	1.63%
Total
Number of securities | security	12	25
Fair Value	$ 30,427	$ 61,087
Unrealized Loss	$ (137)	$ (808)
Percent of Unrealized Loss	0.45%	1.32%
Other securities (FHLB, FHLMC and FNMA) [Member]
Less than 12 months
Number of securities | security	0	0
Fair Value	$ 0	$ 0
Unrealized Loss	$ 0	$ 0
Percent of Unrealized Loss	0.00%	0.00%
12 months or more
Number of securities | security	6	14
Fair Value	$ 15,229	$ 34,871
Unrealized Loss	$ (58)	$ (500)
Percent of Unrealized Loss	0.38%	1.43%
Total
Number of securities | security	6	14
Fair Value	$ 15,229	$ 34,871
Unrealized Loss	$ (58)	$ (500)
Percent of Unrealized Loss	0.38%	1.43%
State and political subdivisions [Member]
Less than 12 months
Number of securities | security	66	113
Fair Value	$ 17,881	$ 31,022
Unrealized Loss	$ (119)	$ (162)
Percent of Unrealized Loss	0.67%	0.52%
12 months or more
Number of securities | security	20	325
Fair Value	$ 3,825	$ 77,921
Unrealized Loss	$ (16)	$ (1,666)
Percent of Unrealized Loss	0.42%	2.14%
Total
Number of securities | security	86	438
Fair Value	$ 21,706	$ 108,943
Unrealized Loss	$ (135)	$ (1,828)
Percent of Unrealized Loss	0.62%	1.68%