Segment Information (Tables)

3 Months Ended

Mar. 31, 2019

Segment Reporting Information [Line Items]

Schedule of Segment Reporting Information, by Segment [Table Text Block]

Financial data for the business segments are as follows (in thousands):

Three Months Ended
March 31, 2019	Electric			Gas			Other			Eliminations		Total
Operating revenues	$	273,037		$	111,183		$	—		$	—	$	384,220
Cost of sales	76,994			38,741			—			—		115,735
Gross margin	196,043			72,442			—			—		268,485
Operating, general and administrative	57,783			21,008			2,301			—		81,092
Property and other taxes	35,047			9,740			2			—		44,789
Depreciation and depletion	38,051			7,533			—			—		45,584
Operating income (loss)	65,162			34,161			(2,303		)	—		97,020
Interest expense	(19,535		)	(1,510		)	(2,745		)	—		(23,790		)
Other (expense) income	(561		)	(477		)	2,187			—		1,149
Income tax (expense) benefit	(1,809		)	1,079			(843		)	—		(1,573		)
Net income (loss)	$	43,257		$	33,253		$	(3,704	)	$	—	$	72,806
Total assets	$	4,544,043		$	1,151,929		$	4,683		$	—	$	5,700,655
Capital expenditures	$	52,307		$	13,270		$	—		$	—	$	65,577

Three Months Ended
March 31, 2018	Electric			Gas			Other			Eliminations		Total
Operating revenues	$	238,342		$	103,160		$	—		$	—	$	341,502
Cost of sales	57,273			38,804			—			—		96,077
Gross margin	181,069			64,356			—			—		245,425
Operating, general and administrative	54,648			21,219			(1,522		)	—		74,345
Property and other taxes	33,493			9,318			2			—		42,813
Depreciation and depletion	36,153			7,594			8			—		43,755
Operating income	56,775			26,225			1,512			—		84,512
Interest expense	(19,520		)	(1,854		)	(1,596		)	—		(22,970		)
Other income (expense)	490			108			(1,727		)	—		(1,129		)
Income tax (expense) benefit	(498		)	(2,226		)	810			—		(1,914		)
Net income (loss)	$	37,247		$	22,253		$	(1,001	)	$	—	$	58,499
Total assets	$	4,319,798		$	1,065,103		$	15,517		$	—	$	5,400,418
Capital expenditures	$	42,898		$	9,107		$	—		$	—	$	52,005