XML 128 R113.htm IDEA: XBRL DOCUMENT v3.20.4
Retirement Benefit Plans (Changes in Benefit Obligations and Plan Assets) (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Pension Benefits [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Benefit obligation, beginning of year $ 581,866 $ 492,017  
Service cost 12,898 10,981 $ 12,414
Interest cost 16,207 18,843 16,762
Net actuarial loss 70,777 81,166  
Benefits paid (21,439) (21,141)  
Benefit obligation, end of year 660,309 581,866 492,017
Fair value of plan assets, beginning of year 752,138 542,618  
Actual return on plan assets 84,810 130,745  
Employer contributions 1,178 101,165  
Benefit payments (21,439) (21,141)  
Expenses (1,383) (1,249)  
Fair value of plan assets, end of year 815,304 752,138 542,618
Funded status at end of year - net asset (liability) 154,995 170,272  
Unrecognized loss at beginning of year 136,252 149,470  
Net actuarial loss (gain) 28,518 (13,218)  
Unrecognized gain (loss) at end of year 164,770 136,252 149,470
Accumulated benefit obligation 624,999 550,005  
Other Post-Retirement Benefits [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Benefit obligation, beginning of year 16,713 16,283  
Service cost 105 95 120
Interest cost 484 621 621
Plan participants' contributions 538 547  
Net actuarial loss 1,910 733  
Benefits paid (1,420) (1,566)  
Benefit obligation, end of year 18,330 16,713 16,283
Employer contributions 882 1,019  
Plan participants' contributions 538 547  
Benefit payments (1,420) (1,566)  
Funded status at end of year - net asset (liability) (18,330) (16,713)  
Unrecognized loss at beginning of year (5,369) (7,015)  
Net actuarial loss (gain) 2,565 1,646  
Unrecognized gain (loss) at end of year $ (2,804) $ (5,369) $ (7,015)