Employee Benefit Plans (Components Of Net Benefit Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement	$ (1,477)	$ 0
Defined Benefit Plan, Service Cost	2,694	2,993
Interest cost on benefits obligation	10,061	9,164
Expected return on assets	(11,979)	(15,418)
Defined Benefit Plan, Plan Assets, Payment for Settlement		2,400
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	329
Cost of 401(k) plan company contributions	3,428	1,847	$ 1,978
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	2,694	2,993	181
Interest cost on benefits obligation		9,164	2,158
Expected return on assets		(15,418)	(2,994)
Net pension costs and return	776	(3,261)	(655)
Net loss amortization	441	153	735
Total amortization items	456	153	735
Pension and Other Postretirement Benefits Cost (Reversal of Cost)	1,232	(3,108)	80
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement	0	0
Defined Benefit Plan, Service Cost	2	1	0
Interest cost on benefits obligation	359	336	20
Expected return on assets	0		0
Net loss amortization	(32)		0
Total amortization items	(32)		0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ 361	$ 337	$ 20