Leases - Narrative (Details)	3 Months Ended
	Mar. 31, 2020 USD ($) item	Dec. 31, 2019 USD ($)
Leases
Number of leased branch offices | item	7
Weighted average remaining life of the lease terms	13 years 3 months 18 days
Weighted average discount rate	2.62%
Operating lease costs	$ 155,000,000
Deferred Rent Credit	204,000	$ 213,000
Operating lease right-of-use asset	$ 6,600,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Other Assets
Operating lease liability	$ 6,600,000
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Accrued Liabilities and Other Liabilities