XML 18 R6.htm IDEA: XBRL DOCUMENT v3.8.0.1
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Parenthetical) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Statement of Comprehensive Income [Abstract]      
Change in employees plan assets and benefit obligations, tax $ 171 $ 184 $ 96