Retirement Benefit Plans (Components of Net Periodic (Benefits) Cost) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Total recognized in other comprehensive income	$ 24,139	$ 6,735	$ (37,451)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	11,438	11,616	12,898
Interest cost	$ 14,639	$ 13,476	$ 16,207
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Interest Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Payroll Taxes Healthcare Costs Pension And Other Postretirement Benefit Expense	Payroll Taxes Healthcare Costs Pension And Other Postretirement Benefit Expense	Payroll Taxes Healthcare Costs Pension And Other Postretirement Benefit Expense
Expected return on plan assets	$ (46,615)	$ (46,654)	$ (48,191)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Expected Return (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Payroll Taxes Healthcare Costs Pension And Other Postretirement Benefit Expense	Payroll Taxes Healthcare Costs Pension And Other Postretirement Benefit Expense	Payroll Taxes Healthcare Costs Pension And Other Postretirement Benefit Expense
Special termination benefits		$ 16,052
Amortization of net (gain) loss/ prior service cost	$ 2,830	$ 5,284	$ 7,021
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Payroll Taxes Healthcare Costs Pension And Other Postretirement Benefit Expense	Payroll Taxes Healthcare Costs Pension And Other Postretirement Benefit Expense	Payroll Taxes Healthcare Costs Pension And Other Postretirement Benefit Expense
Net periodic (benefit) cost	$ (17,708)	$ (226)	$ (12,065)
Net (loss) gain recognized during the year	(2,830)	(5,284)	(7,021)
Net actuarial loss (gain)	29,952	(51,365)	35,539
Total recognized in other comprehensive income	27,122	(56,649)	28,518
Total recognized in net periodic benefit cost and other comprehensive income	$ 9,414	$ (56,875)	$ 16,453
Discount rate for benefit obligations	5.00%	2.77%	2.40%
Discount rate for net periodic benefit cost	2.77%	2.40%	3.14%
Expected long-term return on plan assets	5.50%	5.75%	6.50%
Pension Benefits [Member] | Graded Scale, 7.25% At Age 20 [Member]
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase	7.25%	7.25%	7.25%
Pension Benefits [Member] | Graded Scale, 2.25% At Age 60 [Member]
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase	2.25%	2.25%	2.25%
Pension Benefits [Member] | Graded Scale, 2.25% At Age 65 [Member]
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase	2.25%	2.25%	2.25%
Other Post-Retirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 59	$ 93	$ 105
Interest cost	$ 375	$ 348	$ 484
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Interest Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Payroll Taxes Healthcare Costs Pension And Other Postretirement Benefit Expense	Payroll Taxes Healthcare Costs Pension And Other Postretirement Benefit Expense	Payroll Taxes Healthcare Costs Pension And Other Postretirement Benefit Expense
Special termination benefits		$ 4,173
Amortization of net (gain) loss/ prior service cost	$ (650)	$ (729)	$ (653)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Payroll Taxes Healthcare Costs Pension And Other Postretirement Benefit Expense	Payroll Taxes Healthcare Costs Pension And Other Postretirement Benefit Expense	Payroll Taxes Healthcare Costs Pension And Other Postretirement Benefit Expense
Net periodic (benefit) cost	$ (216)	$ 3,885	$ (64)
Net (loss) gain recognized during the year	650	729	653
Net actuarial loss (gain)	(5,906)	(1,506)	1,912
Total recognized in other comprehensive income	(5,256)	(777)	2,565
Total recognized in net periodic benefit cost and other comprehensive income	$ (5,472)	$ 3,108	$ 2,501
Discount rate for benefit obligations	4.98%	2.32%	2.31%
Discount rate for net periodic benefit cost	2.32%	2.31%	3.11%