Defined Benefit Pension Plans (Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Qualified Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	[1]	$ 592	$ 541	$ 1,777	$ 1,623
Interest cost	[2]	500	626	1,502	1,879
Expected return on plan assets	[2]	(1,203)	(1,135)	(3,611)	(3,404)
Recognized net actuarial loss	[2]	531	396	1,591	1,187
Net periodic benefit cost		420	428	1,259	1,285
Non-Qualified Retirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	[1]	52	43	156	128
Interest cost	[2]	84	116	253	349
Expected return on plan assets	[2]	0	0	0	0
Recognized net actuarial loss	[2]	180	139	542	419
Net periodic benefit cost		$ 316	$ 298	$ 951	$ 896

[1] Included in salaries and employee benefits expense in the Unaudited Consolidated Statements of Income.

[2] Included in other expenses in the Unaudited Consolidated Statements of Income.