Segment financial information (Tables)

9 Months Ended

Sep. 30, 2015

Segment Reporting [Abstract]

Schedule of segment financial information

(in thousands)	Electric utility		Bank		Other			Total
Three months ended September 30, 2015
Revenues from external customers	$	648,121	$	69,091	$	(36	)	$	717,176
Intersegment revenues (eliminations)	6		—		(6		)	—
Revenues	648,127		69,091		(42		)	717,176
Income (loss) before income taxes	68,894		20,802		(9,036		)	80,660
Income taxes (benefit)	25,390		7,351		(3,225		)	29,516
Net income (loss)	43,504		13,451		(5,811		)	51,144
Preferred stock dividends of subsidiaries	498		—		(27		)	471
Net income (loss) for common stock	43,006		13,451		(5,784		)	50,673
Nine months ended September 30, 2015
Revenues from external customers	$	1,779,708	$	199,222	$	20		$	1,978,950
Intersegment revenues (eliminations)	24		—		(24		)	—
Revenues	1,779,732		199,222		(4		)	1,978,950
Income (loss) before income taxes	164,568		61,159		(36,347		)	189,380
Income taxes (benefit)	60,351		21,382		(11,327		)	70,406
Net income (loss)	104,217		39,777		(25,020		)	118,974
Preferred stock dividends of subsidiaries	1,496		—		(79		)	1,417
Net income (loss) for common stock	102,721		39,777		(24,941		)	117,557
Assets (at September 30, 2015)	5,683,992		5,855,497		33,977			11,573,466
Three months ended September 30, 2014
Revenues from external customers	$	803,559	$	63,536	$	1		$	867,096
Intersegment revenues (eliminations)	6		—		(6		)	—
Revenues	803,565		63,536		(5		)	867,096
Income (loss) before income taxes	62,419		20,506		(7,382		)	75,543
Income taxes (benefit)	23,042		7,253		(3,031		)	27,264
Net income (loss)	39,377		13,253		(4,351		)	48,279
Preferred stock dividends of subsidiaries	498		—		(27		)	471
Net income (loss) for common stock	38,879		13,253		(4,324		)	47,808
Nine months ended September 30, 2014
Revenues from external customers	$	2,262,038	$	187,771	$	(307	)	$	2,449,502
Intersegment revenues (eliminations)	18		—		(18		)	—
Revenues	2,262,056		187,771		(325		)	2,449,502
Income (loss) before income taxes	174,711		60,994		(23,110		)	212,595
Income taxes (benefit)	64,686		21,806		(10,190		)	76,302
Net income (loss)	110,025		39,188		(12,920		)	136,293
Preferred stock dividends of subsidiaries	1,496		—		(79		)	1,417
Net income (loss) for common stock	108,529		39,188		(12,841		)	134,876
Assets (at December 31, 2014)	5,590,457		5,566,222		28,463			11,185,142