Segment Information (Tables)

3 Months Ended

Mar. 31, 2019

Segment Reporting [Abstract]

Schedule of Segment Reporting Information

The following tables present revenues from external customers, intersegment revenues, and segment net income for the two reportable segments (thousands of dollars):

	Natural Gas Operations		Utility Infrastructure Services			Other			Total
Three Months Ended March 31, 2019
Revenues from external customers	$	520,677	$	274,189		$	—		$	794,866
Intersegment revenues	—		38,673			—			38,673
Total	$	520,677	$	312,862		$	—		$	833,539
Segment net income (loss)	$	103,389	$	(8,031	)	$	(549	)	$	94,809
Three Months Ended March 31, 2018
Revenues from external customers	$	494,313	$	232,859		$	—		$	727,172
Intersegment revenues	—		27,158			—			27,158
Total	$	494,313	$	260,017		$	—		$	754,330
Segment net income (loss)	$	90,349	$	(11,001	)	$	(257	)	$	79,091
	Natural Gas Operations		Utility Infrastructure Services			Other			Total
Twelve Months Ended March 31, 2019
Revenues from external customers	$	1,384,092	$	1,427,701		$	—		$	2,811,793
Intersegment revenues	—		147,429			—			147,429
Total	$	1,384,092	$	1,575,130		$	—		$	2,959,222
Segment net income (loss)	$	151,882	$	47,947		$	(1,834	)	$	197,995
Twelve Months Ended March 31, 2018
Revenues from external customers	$	1,334,019	$	1,211,345		$	—		$	2,545,364
Intersegment revenues	—		103,021			—			103,021
Total	$	1,334,019	$	1,314,366		$	—		$	2,648,385
Segment net income (loss)	$	170,229	$	34,693		$	(1,298	)	$	203,624