Investment Securities - Allowance for Credit Losses for HTM Securities (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Beginning Balance / Day One Impact of adopting ASC 326	$ 222	$ 0
Provision for Credit Losses	69	117
Ending Balance	291	291
Municipal bonds and notes
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Beginning Balance / Day One Impact of adopting ASC 326	222	0
Provision for Credit Losses	69	117
Ending Balance	$ 291	291
Cumulative adjustment for the adoption of amendment
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Beginning Balance / Day One Impact of adopting ASC 326		174
Cumulative adjustment for the adoption of amendment | Municipal bonds and notes
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Beginning Balance / Day One Impact of adopting ASC 326		$ 174