Premises and Equipment - Narrative (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)
Leases [Abstract]
Lease liability	$ 19.6	$ 19.6
Right-of-use asset	$ 18.3	$ 18.3
Finance lease, weighted average remaining lease term (in years)		2 years 2 months 12 days
Finance lease, weighted average discount rate, (as a percentage)		2.80%
Operating lease, weighted average remaining lease term (in years)	10 years 9 months 18 days	10 years 9 months 18 days
Operating lease, weighted average discount rate, (as a percentage)	3.33%	3.33%