v3.20.4
EMPLOYEE BENEFIT PLANS Table 1 - Changes in Benefit Obligation/Fair Value of Plan Assets/Funded Status/Amounts Recognized in Consolidated Balance Sheets (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2020
Dec. 31, 2019
Pension Plan [Member]          
Change in benefit obligation:          
Benefit obligation, January 1 $ 167,257 $ 141,833      
Service cost 9,174 9,549 $ 9,621    
Interest cost 4,693 5,480 4,824    
Benefits paid (9,520) (7,109)      
Participant contributions 0 0      
Actuarial loss (gain) 15,081 17,504      
Benefit obligation, December 31 186,685 167,257 141,833    
Change in plan assets:          
Plan assets at fair value, January 1 159,036 126,949      
Actual return on plan assets 21,758 28,064      
Employer contributions 11,453 11,132      
Benefits paid (9,520) (7,109)      
Participant contributions 0 0      
Plan assets at fair value, December 31 182,727 159,036 126,949    
Reconciliation of funded status:          
Fair value of plan assets at December 31 159,036 159,036 126,949 $ 182,727 $ 159,036
Less: Benefit obligation at December 31 167,257 167,257 141,833 186,685 167,257
Funded status at December 31       (3,958) (8,221)
Amounts recognized in the consolidated balance sheets:          
Accrued liabilities       (382) (303)
Other long-term liabilities       (3,576) (7,918)
Net pension liability       (3,958) (8,221)
Accumulated benefit obligation for the Pension Plans       181,263 164,183
Pension Plan [Member] | Excess Pension Plan [Member]          
Change in plan assets:          
Plan assets at fair value, January 1 0        
Plan assets at fair value, December 31 0 0      
Reconciliation of funded status:          
Fair value of plan assets at December 31 0 0   0 0
Amounts recognized in the consolidated balance sheets:          
Accumulated benefit obligation for the Pension Plans       3,800 3,700
Pension Plan [Member] | Excess Pension Plan and Other Postretirement Benefit Plans          
Change in plan assets:          
Plan assets at fair value, January 1 0        
Plan assets at fair value, December 31 0 0      
Reconciliation of funded status:          
Fair value of plan assets at December 31 0 0   0 0
Other Postretirement Benefit Plans [Member]          
Change in benefit obligation:          
Benefit obligation, January 1 13,196 10,908      
Service cost 529 431 504    
Interest cost 399 453 429    
Benefits paid (281) (217)      
Participant contributions 44 62      
Actuarial loss (gain) 793 1,559      
Benefit obligation, December 31 14,680 13,196 10,908    
Change in plan assets:          
Plan assets at fair value, January 1 0 0      
Actual return on plan assets 0 0      
Employer contributions 237 155      
Benefits paid (281) (217)      
Participant contributions 44 62      
Plan assets at fair value, December 31 0 0 0    
Reconciliation of funded status:          
Fair value of plan assets at December 31 0 0 0 0 0
Less: Benefit obligation at December 31 $ 13,196 $ 13,196 $ 10,908 14,680 13,196
Funded status at December 31       (14,680) (13,196)
Amounts recognized in the consolidated balance sheets:          
Accrued liabilities       (352) (368)
Other long-term liabilities       (14,328) (12,828)
Net pension liability       (14,680) (13,196)
Accumulated benefit obligation for the Pension Plans       $ 14,680 $ 13,196