Quarterly report pursuant to Section 13 or 15(d)

Postretirement Benefits Textuals (Details)

v3.7.0.1
Postretirement Benefits Textuals (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Compensation and Retirement Disclosure [Abstract]    
Defined Benefit Plan, Contributions by Employer $ 0 $ 1,181