Defined Benefit Pension Plans (Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Qualified Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	[1]	$ 592	$ 541
Interest cost	[2]	645	626
Expected return on plan assets	[2]	(1,204)	(1,135)
Recognized net actuarial loss	[2]	387	396
Net periodic benefit cost		420	428
Non-Qualified Retirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	[1]	52	43
Interest cost	[2]	84	116
Expected return on plan assets	[2]	0	0
Recognized net actuarial loss	[2]	158	140
Net periodic benefit cost		$ 294	$ 299

[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.