Segment financial information (Tables)

3 Months Ended

Mar. 31, 2015

Segment Reporting [Abstract]

Schedule of segment financial information

(in thousands)	Electric utility		Bank		Other			Total
Three months ended March 31, 2015
Revenues from external customers	$	573,431	$	64,348	$	83		$	637,862
Intersegment revenues (eliminations)	11		—		(11		)	—
Revenues	573,442		64,348		72			637,862
Income (loss) before income taxes	43,223		20,631		(11,536		)	52,318
Income taxes (benefit)	15,850		7,156		(3,027		)	19,979
Net income (loss)	27,373		13,475		(8,509		)	32,339
Preferred stock dividends of subsidiaries	499		—		(26		)	473
Net income (loss) for common stock	26,874		13,475		(8,483		)	31,866
Assets (at March 31, 2015)	5,535,500		5,724,877		13,070			11,273,447
Three months ended March 31, 2014
Revenues from external customers	$	720,056	$	63,619	$	74		$	783,749
Intersegment revenues (eliminations)	6		—		(6		)	—
Revenues	720,062		63,619		68			783,749
Income (loss) before income taxes	57,166		22,532		(7,717		)	71,981
Income taxes (benefit)	21,247		8,133		(3,659		)	25,721
Net income (loss)	35,919		14,399		(4,058		)	46,260
Preferred stock dividends of subsidiaries	499		—		(26		)	473
Net income (loss) for common stock	35,420		14,399		(4,032		)	45,787
Assets (at December 31, 2014)	5,590,457		5,566,222		28,463			11,185,142