Investment Securities - Allowance for Credit Losses for HTM Securities (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Beginning Balance / Day One Impact of adopting ASC 326	$ 230	$ 0
Provision for Credit Losses	(8)	48
Ending Balance	222	222
Municipal bonds and notes
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Beginning Balance / Day One Impact of adopting ASC 326	230	0
Provision for Credit Losses	(8)	48
Ending Balance	222	222
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	0	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	$ 0	$ 174