Defined Benefit Pension Plans (Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Qualified Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	[1]	$ 541	$ 509
Interest cost	[2]	626	742
Expected return on plan assets	[2]	(1,135)	(1,124)
Amortization of prior service (credit) cost	[2]	0	(4)
Recognized net actuarial loss	[2]	396	198
Net periodic benefit cost		428	321
Non-Qualified Retirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	[1]	43	31
Interest cost	[2]	116	141
Expected return on plan assets	[2]	0	0
Amortization of prior service (credit) cost	[2]	0	0
Recognized net actuarial loss	[2]	140	102
Net periodic benefit cost		$ 299	$ 274

[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.