Segment financial information (Tables)

3 Months Ended

Mar. 31, 2018

Segment Reporting [Abstract]

Schedule of segment financial information

(in thousands)	Electric utility		Bank		Other			Total
Three months ended March 31, 2018
Revenues from external customers	$	570,414	$	75,419	$	41		$	645,874
Intersegment revenues (eliminations)	13		—		(13		)	—
Revenues	$	570,427	$	75,419	$	28		$	645,874
Income (loss) before income taxes	$	37,149	$	24,500	$	(8,373	)	$	53,276
Income taxes (benefit)	9,175		5,540		(2,159		)	12,556
Net income (loss)	27,974		18,960		(6,214		)	40,720
Preferred stock dividends of subsidiaries	499		—		(26		)	473
Net income (loss) for common stock	$	27,475	$	18,960	$	(6,188	)	$	40,247
Total assets (at March 31, 2018)	$	5,710,569	$	6,889,445	$	102,704		$	12,702,718
Three months ended March 31, 2017
Revenues from external customers	$	518,566	$	72,856	$	140		$	591,562
Intersegment revenues (eliminations)	45		—		(45		)	—
Revenues	$	518,611	$	72,856	$	95		$	591,562
Income before income taxes	$	34,722	$	24,160	$	(7,300	)	$	51,582
Income taxes	12,758		8,347		(4,189		)	16,916
Net income	21,964		15,813		(3,111		)	34,666
Preferred stock dividends of subsidiaries	499		—		(26		)	473
Net income for common stock	$	21,465	$	15,813	$	(3,085	)	$	34,193
Total assets (at December 31, 2017)	$	5,630,613	$	6,798,659	$	104,888		$	12,534,160