QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||
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Dec. 31, 2017 |
Sep. 30, 2017 |
Jun. 30, 2017 |
Mar. 31, 2017 |
Dec. 31, 2016 |
Sep. 30, 2016 |
Jun. 30, 2016 |
Mar. 31, 2016 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
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Schedule of Quarterly Financial Information [Line Items] | |||||||||||
Revenues | $ 462,394 | $ 247,142 | $ 279,689 | $ 550,408 | $ 440,754 | $ 232,191 | $ 245,923 | $ 508,364 | $ 1,539,633 | $ 1,427,232 | $ 1,547,692 |
Net margin | 925,132 | 885,435 | 841,733 | ||||||||
Operating income | 89,512 | 40,780 | 44,052 | 125,132 | 78,534 | 30,892 | 43,621 | 116,073 | 299,476 | 269,120 | 239,129 |
Net income | $ 47,119 | $ 18,797 | $ 20,623 | $ 76,456 | $ 42,315 | $ 12,737 | $ 20,300 | $ 64,743 | $ 162,995 | $ 140,095 | $ 119,030 |
Basic | $ 0.90 | $ 0.36 | $ 0.39 | $ 1.45 | $ 0.81 | $ 0.24 | $ 0.39 | $ 1.23 | $ 3.10 | $ 2.67 | $ 2.26 |
Diluted | $ 0.89 | $ 0.36 | $ 0.39 | $ 1.44 | $ 0.80 | $ 0.24 | $ 0.38 | $ 1.22 | $ 3.08 | $ 2.65 | $ 2.24 |
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- Definition [Line Items] for Schedule of Quarterly Financial Information [Table] No definition available.
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- Definition The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The net result for the period of deducting operating expenses from operating revenues. No definition available.
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- Definition The amount of regulated gas operating revenues recognized during the period. No definition available.
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