Description of Business and Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2016

Accounting Policies [Abstract]

Schedule of Provision for Depreciation of Electric Plant

Provision for depreciation of electric plant is computed using composite straight-line rates as follows:

	Years Ended December 31,
	2016	2015	2014
Transmission plant	1.69% -3.15%	1.69% -3.15%	1.69% - 3.15%
Distribution plant	1.74% - 5.96%	1.74% - 5.96%	1.74% - 5.96%
General plant	0.80% - 5.12%	0.80% - 5.12%	0.80% - 5.12%

Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of unrecognized tax benefits follows:

	Years Ended December 31,
(In thousands)	2016		2015
Balance at January 1	$	2,924	$	2,135
Additions based on tax positions related to the current year		903		789
Balance at December 31	$	3,827	$	2,924