Defined Benefit Pension Plans (Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Qualified Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	[1]	$ 593	$ 541	$ 1,185	$ 1,082
Interest cost	[2]	357	627	1,002	1,253
Expected return on plan assets	[2]	(1,204)	(1,134)	(2,408)	(2,269)
Recognized net actuarial loss	[2]	673	395	1,060	791
Net periodic benefit cost		419	429	839	857
Non-Qualified Retirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	[1]	52	42	104	85
Interest cost	[2]	85	117	169	233
Expected return on plan assets	[2]	0	0	0	0
Recognized net actuarial loss	[2]	204	140	362	280
Net periodic benefit cost		$ 341	$ 299	$ 635	$ 598

[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.