Property, Plant and Equipment

3 Months Ended

Mar. 31, 2018

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

Property, Plant and Equipment

Property, plant and equipment consisted of the following:

(in thousands)	March 31, 2018		December 31, 2017
Plant in service	$	1,245,079	$	1,219,185
Plant under construction	57,005		62,202
	1,302,084		1,281,387
Less accumulated amortization and depreciation	630,067		595,060
Net property, plant and equipment	$	672,017	$	686,327