XML 100 R85.htm IDEA: XBRL DOCUMENT v3.6.0.2
Postretirement benefits (cash flows) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Postretirement benefit plan [Member]      
Postretirement benefits [Line Items]      
Company contributions $ 0 $ 0 $ 0
Expected benefit payments      
2017 9,037    
2018 9,379    
2019 9,166    
2020 8,696    
2021 8,210    
2022 - 2026 33,410    
Pension plan [Member]      
Postretirement benefits [Line Items]      
Cash surrender value of insurance polices which fund pension plan 6,362 $ 7,573  
Expected benefit payments      
2017 320    
2018 320    
2019 310    
2020 310    
2021 300    
2022 - 2026 $ 1,390