Leases (Narrative) (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2020 numberOfOption lease	Dec. 31, 2019 lease
Lessee, Lease, Description [Line Items]
Number of operating leases		37
Number of option to extend | numberOfOption	1
Weighted average remaining lease term	14 years 9 months 18 days
Weighted average discount rate	3.34%
Building
Lessee, Lease, Description [Line Items]
Number of operating leases		23
Building, Branch Offices
Lessee, Lease, Description [Line Items]
Number of operating leases		19
Building, General Office Space
Lessee, Lease, Description [Line Items]
Number of operating leases		4
Land
Lessee, Lease, Description [Line Items]
Number of operating leases	4
Office Equipment
Lessee, Lease, Description [Line Items]
Number of operating leases		12
Office Equipment | Minimum
Lessee, Lease, Description [Line Items]
Operating lease, term of contract	3 years
Office Equipment | Maximum
Lessee, Lease, Description [Line Items]
Operating lease, term of contract	5 years
Automobiles
Lessee, Lease, Description [Line Items]
Number of operating leases	2
Automobiles | Minimum
Lessee, Lease, Description [Line Items]
Operating lease, term of contract	3 years
Automobiles | Maximum
Lessee, Lease, Description [Line Items]
Operating lease, term of contract	5 years