Segment financial information (Tables)

12 Months Ended

Dec. 31, 2016

Segment Reporting [Abstract]

Schedule of segment financial information

Segment financial information was as follows:

(in thousands)	Electric utility		Bank		Other			Total
2016
Revenues from external customers	$	2,094,224	$	285,924	$	506		$	2,380,654
Intersegment revenues (eliminations)	144		—		(144		)	—
Revenues	2,094,368		285,924		362			2,380,654
Depreciation and amortization	193,996		9,813		937			204,746
Interest expense, net	66,824		12,755		8,979			88,558
Income before income taxes	229,113		87,352		57,376			373,841
Income taxes	84,801		30,073		8,821			123,695
Net income	144,312		57,279		48,555			250,146
Preferred stock dividends of subsidiaries	1,995		—		(105		)	1,890
Net income for common stock	142,317		57,279		48,660			248,256
Capital expenditures	320,437		9,394		212			330,043
Assets (at December 31, 2016)	5,975,428		6,421,357		28,721			12,425,506
2015
Revenues from external customers	$	2,335,135	$	267,733	$	114		$	2,602,982
Intersegment revenues (eliminations)	31		—		(31		)	—
Revenues	2,335,166		267,733		83			2,602,982
Depreciation and amortization	186,319		7,928		1,338			195,585
Interest expense, net	66,370		11,326		10,780			88,476
Income (loss) before income taxes	217,131		83,812		(46,155		)	254,788
Income taxes (benefit)	79,422		29,082		(15,483		)	93,021
Net income (loss)	137,709		54,730		(30,672		)	161,767
Preferred stock dividends of subsidiaries	1,995		—		(105		)	1,890
Net income (loss) for common stock	135,714		54,730		(30,567		)	159,877
Capital expenditures	350,161		13,470		173			363,804
Assets (at December 31, 2015)	5,672,210		6,014,755		95,053			11,782,018
2014
Revenues from external customers	$	2,987,299	$	252,497	$	(254	)	$	3,239,542
Intersegment revenues (eliminations)	24		—		(24		)	—
Revenues	2,987,323		252,497		(278		)	3,239,542
Depreciation and amortization	176,284		5,399		1,361			183,044
Interest expense, net	64,757		10,808		11,595			87,160
Income (loss) before income taxes	220,361		79,295		(34,058		)	265,598
Income taxes (benefit)	80,725		27,994		(13,140		)	95,579
Net income (loss)	139,636		51,301		(20,918		)	170,019
Preferred stock dividends of subsidiaries	1,995		—		(105		)	1,890
Net income (loss) for common stock	137,641		51,301		(20,813		)	168,129
Capital expenditures	336,679		28,073		74			364,826
Assets (at December 31, 2014)	5,550,021		5,566,222		60,900			11,177,143