XML 72 R56.htm IDEA: XBRL DOCUMENT v3.10.0.1
Inventories (Narrative) (Details) - USD ($)
$ in Thousands
Dec. 31, 2018
Dec. 31, 2017
Inventory Disclosure [Abstract]    
Percentage of LIFO inventory 60.00% 62.00%
Excess of current costs over stated LIFO value $ 10,646 $ 7,919