Defined Benefit Pension Plans (Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Qualified Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	[1]	$ 541	$ 509	$ 1,082	$ 1,018
Interest cost	[2]	627	742	1,253	1,484
Expected return on plan assets	[2]	(1,134)	(1,123)	(2,269)	(2,247)
Amortization of prior service (credit) cost	[2]	0	(4)	0	(8)
Recognized net actuarial loss	[2]	395	198	791	396
Net periodic benefit cost		429	322	857	643
Non-Qualified Retirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	[1]	42	32	85	63
Interest cost	[2]	117	141	233	282
Expected return on plan assets	[2]	0	0	0	0
Amortization of prior service (credit) cost	[2]	0	0	0	0
Recognized net actuarial loss	[2]	140	101	280	203
Net periodic benefit cost		$ 299	$ 274	$ 598	$ 548

[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.