Securities - Gross Unrealized Losses and Fair Value of Company's Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Schedule of Available-for-sale Securities [Line Items]
Fair Value less than 12 months	$ 69,886	$ 224,138
Unrealized losses less than 12 months	(657)	(2,788)
Fair value more than 12 months	4,885	67,402
Unrealized losses more than 12 months	(108)	(574)
Total fair value	74,771	291,540
Total unrealized losses	765	3,362
U.S. Treasury and federal agencies
Schedule of Available-for-sale Securities [Line Items]
Fair Value less than 12 months		1,413
Unrealized losses less than 12 months		(2)
Fair value more than 12 months		0
Unrealized losses more than 12 months		0
Total fair value		1,413
Total unrealized losses		2
State and municipal
Schedule of Available-for-sale Securities [Line Items]
Fair Value less than 12 months	66,448	129,942
Unrealized losses less than 12 months	(651)	(2,374)
Fair value more than 12 months	4,885	6,279
Unrealized losses more than 12 months	(108)	(131)
Total fair value	71,333	136,221
Total unrealized losses	759	2,505
Federal agency collateralized mortgage obligations
Schedule of Available-for-sale Securities [Line Items]
Fair Value less than 12 months	3,438	68,043
Unrealized losses less than 12 months	(6)	(308)
Fair value more than 12 months	0	23,301
Unrealized losses more than 12 months	0	(260)
Total fair value	3,438	91,344
Total unrealized losses	$ 6	568
Federal agency mortgage-backed pools
Schedule of Available-for-sale Securities [Line Items]
Fair Value less than 12 months		24,740
Unrealized losses less than 12 months		(104)
Fair value more than 12 months		37,822
Unrealized losses more than 12 months		(183)
Total fair value		62,562
Total unrealized losses		287
Corporate notes
Schedule of Available-for-sale Securities [Line Items]
Fair Value less than 12 months		0
Unrealized losses less than 12 months		0
Fair value more than 12 months		0
Unrealized losses more than 12 months		0
Total fair value		0
Total unrealized losses		$ 0