Defined Benefit Pension Plans (Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Qualified Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	[1]	$ 541	$ 510	$ 1,623	$ 1,528
Interest cost	[2]	626	741	1,879	2,225
Expected return on plan assets	[2]	(1,135)	(1,124)	(3,404)	(3,371)
Amortization of prior service (credit) cost	[2]	0	(4)	0	(12)
Recognized net actuarial loss	[2]	396	198	1,187	594
Net periodic benefit cost		428	321	1,285	964
Non-Qualified Retirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	[1]	43	31	128	94
Interest cost	[2]	116	140	349	422
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]	139	104	419	307
Net periodic benefit cost		$ 298	$ 275	$ 896	$ 823

[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.