Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Operating revenues:
Electric, natural gas distribution and pipeline and energy services	$ 254,689	$ 227,442	$ 746,231	$ 651,565
Exploration and production, construction materials and contracting, construction services and other	839,357	833,153	1,390,668	1,340,633
Total operating revenues	1,094,046	1,060,595	2,136,899	1,992,198
Operating expenses:
Fuel and purchased power	21,046	18,169	47,590	39,777
Purchased natural gas sold	84,415	70,255	329,307	269,442
Operation and maintenance:
Electric, natural gas distribution and pipeline and energy services	61,764	76,627	129,047	142,730
Exploration and production, construction materials and contracting, construction services and other	675,330	661,495	1,121,282	1,055,511
Depreciation, depletion and amortization	103,126	95,289	202,683	188,850
Taxes, other than income	49,431	47,382	105,152	99,979
Total operating expenses	995,112	969,217	1,935,061	1,796,289
Operating income	98,934	91,378	201,838	195,909
Loss from equity method investments	(297)	(7)	(245)	(319)
Other income	2,777	1,436	4,908	2,677
Interest expense	21,516	21,427	42,487	42,300
Income before income taxes	79,898	71,380	164,014	155,967
Income taxes	27,118	24,988	55,050	52,983
Income from continuing operations	52,780	46,392	108,964	102,984
Income (loss) from discontinued operations, net of tax (Note 11)	547	(59)	502	(136)
Net income	53,327	46,333	109,466	102,848
Net loss attributable to noncontrolling interest	(779)	(179)	(1,302)	(179)
Dividends declared on preferred stocks	171	171	342	342
Earnings on common stock	$ 53,935	$ 46,341	$ 110,426	$ 102,685
Earnings per common share - basic:
Earnings before discontinued operations	$ 0.28	$ 0.25	$ 0.58	$ 0.54
Discontinued operations, net of tax	$ 0.00	$ 0.00	$ 0.00	$ 0.00
Earnings per common share - basic	$ 0.28	$ 0.25	$ 0.58	$ 0.54
Earnings per common share - diluted:
Earnings before discontinued operations	$ 0.28	$ 0.24	$ 0.58	$ 0.54
Discontinued operations, net of tax	$ 0.00	$ 0.00	$ 0.00	$ 0.00
Earnings per common share - diluted	$ 0.28	$ 0.24	$ 0.58	$ 0.54
Dividends declared per common share	$ 0.1775	$ 0.1725	$ 0.3550	$ 0.3450
Weighted average common shares outstanding - basic	192,060	188,831	190,946	188,831
Weighted average common shares outstanding - diluted	192,659	189,463	191,543	189,460