Investment Securities - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($) Investments	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) Investments	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($) Investments
Schedule of Held-to-maturity Securities [Line Items]
Investment securities classified as held to maturity	$ 55,000,000.0		$ 55,000,000.0		$ 92,300,000
Investment securities in an unrealized loss position (securities) | Investments	127		127		331
Impairment loss	$ 0	$ 0	$ 0	$ 0
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0		0
Municipal Debt Securities, at Carrying Value	$ 41,900,000		$ 41,900,000
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Percent Debt Securities	66.30%		66.30%
State, county and municipal securities
Schedule of Held-to-maturity Securities [Line Items]
Investment securities classified as held to maturity	$ 49,900,000		$ 49,900,000		$ 57,300,000
813940 Political Organizations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Municipal Debt Securities, at Carrying Value	27,800,000		27,800,000
Callable Within One Year
Schedule of Held-to-maturity Securities [Line Items]
Amortized cost of investment securities callable after one year but within five years	252,500,000		252,500,000
Fair value of investment securities callable after one year but within five years	252,500,000		252,500,000
Callable structured notes amortized costs	$ 0		$ 0