Property, Plant and Equipment (Tables)

9 Months Ended

Sep. 30, 2017

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

Property, plant and equipment consisted of the following (in thousands):

	September 30, 2017		December 31, 2016
Plant in service	$	1,187,799	$	1,085,318
Plant under construction	67,099		73,759
	1,254,898		1,159,077
Less accumulated amortization and depreciation	571,543		460,955
Net property, plant and equipment	$	683,355	$	698,122