XML 58 R41.htm IDEA: XBRL DOCUMENT v3.10.0.1
Summary of Significant Accounting Policies (Asset Retirement Obligation) (Details) - USD ($)
$ in Thousands
Dec. 31, 2018
Dec. 31, 2017
Accounting Policies [Abstract]    
Retirement obligation $ 4,803 $ 5,231
Discount rate 6.00% 6.00%
Regulatory asset $ 942 $ 1,184