Annual report pursuant to Section 13 and 15(d)

Employee Retirement Plans - Assumptions (Details)

v3.3.1.900
Employee Retirement Plans - Assumptions (Details)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Dec. 31, 2013
Summary of healthcare cost trend rates        
Assumed health care cost trend rate for the next fiscal year (as a percent)   7.00%    
Ultimate rate in 2024 (as a percent)   4.50%    
Pension plan        
Assumptions used in determining net periodic pension cost for the plans        
Discount rates (as a percent)       4.10%
Expected long-term rate of return on assets (as a percent)   7.25% 7.25% 7.25%
Expected long-term rate of return on plan assets for the next fiscal year 7.25      
Expected benefit payments        
2016   $ 1,380    
2017   1,400    
2018   1,420    
2019   1,410    
2020   1,480    
2021-2025   8,950    
Pension funding contributions made   1,775 $ 1,408  
Required pension funding contributions expected to be made in next fiscal year   967    
Amounts included in other comprehensive loss, net of tax        
Net actuarial gain (loss)   (6,294)    
Amounts that will be amortized from accumulated other comprehensive income loss into net periodic pension or OPEB cost in the next fiscal year        
Estimated actuarial gain (loss)   $ (724)    
Pension plan | Minimum        
Expected benefit payments        
Pension funding contributions made     $ 775  
Salaried Pension Plan [Member]        
Assumptions used in determining net periodic pension cost for the plans        
Rates of increase in compensation levels: Salaried (as a percent)   3.50% 3.50% 3.50%
Assumptions used to determine the benefit obligation        
Discount rate (as a percent)     3.90%  
Hourly Pension Plan [Member]        
Assumptions used to determine the benefit obligation        
Discount rate (as a percent)   4.50% 4.00%  
Other postretirement benefit cost        
Assumptions used in determining net periodic pension cost for the plans        
Discount rates (as a percent)   3.70% 4.50% 3.70%
Summary of healthcare cost trend rates        
Immediate healthcare cost trend rate (as a percent)       7.00%
Ultimate healthcare cost trend rate (as a percent)   4.50% 4.50% 4.50%
Participation (as a percent)   60.00% 60.00% 80.00%
Assumed health care cost trend rate for the next fiscal year (as a percent)       7.00%
Ultimate rate in 2023 (as a percent)     4.50%  
Ultimate rate in 2020 (as a percent)       4.50%
Assumptions used to determine the benefit obligation        
Discount rate (as a percent)   4.50% 3.70%  
Effect of one percentage point change in the healthcare cost trend rate        
Effect on total service and interest cost, 1% increase   $ 63    
Effect on total service and interest cost, 1% decrease   (55)    
Effect on postretirement benefit obligation, 1% increase   773    
Effect on postretirement benefit obligation, 1% decrease   (676)    
Amounts included in other comprehensive loss, net of tax        
Net actuarial gain (loss)   1,048    
Amounts that will be amortized from accumulated other comprehensive income loss into net periodic pension or OPEB cost in the next fiscal year        
Estimated actuarial gain (loss)   $ 127    
Other postretirement benefit cost | Under 65        
Summary of healthcare cost trend rates        
Assumed health care cost trend rate for the next fiscal year (as a percent)     7.00% 7.00%
Other postretirement benefit cost | Over 65        
Summary of healthcare cost trend rates        
Assumed health care cost trend rate for the next fiscal year (as a percent)     6.00% 5.00%