Electric Plant and Depreciation (Tables)

12 Months Ended

Dec. 31, 2016

Public Utilities Property Plant And Equipment [Abstract]

Schedule of Major Classes of Electric Plant

The major classes of electric plant are as follows:

	For the Years Ended December 31,
(In thousands)	2016			2015
Electric plant:
Transmission plant	$	1,203,164		$	1,080,050
Distribution plant		575,648			457,988
General plant		15,959			15,655
Total plant in service		1,794,771			1,553,693
CWIP		107,189			121,602
Total electric plant		1,901,960			1,675,295
Accumulated depreciation		(261,140	)		(240,764	)
Electric plant, net	$	1,640,820		$	1,434,531