Condensed Consolidated Statements of Income (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Revenues
Total revenues	$ 591,562	$ 550,960
Expenses
Other	523,700	482,109
Operating income (loss)
Total operating income	67,862	68,851
Interest expense, net—other than on deposit liabilities and other bank borrowings	(19,568)	(20,126)
Allowance for borrowed funds used during construction	889	662
Allowance for equity funds used during construction	2,399	1,739
Income before income taxes	51,582	51,126
Income taxes	16,916	18,301
Net income	34,666	32,825
Preferred stock dividends of subsidiaries	473	473
Net income for common stock	$ 34,193	$ 32,352
Basic earnings per common share (in dollars per share)	$ 0.31	$ 0.30
Diluted earnings per common share (in dollars per share)	0.31	0.30
Dividends per common share (in dollars per share)	$ 0.31	$ 0.31
Weighted-average number of common shares outstanding (in shares)	108,674	107,620
Net effect of potentially dilutive shares (in shares)	184	161
Weighted-average shares assuming dilution (in shares)	108,858	107,781
Electric utility
Revenues
Total revenues	$ 518,611	$ 482,052
Expenses
Other	469,673	426,726
Operating income (loss)
Total operating income	48,938	55,326
Income before income taxes	34,722	40,419
Income taxes	12,758	14,553
Net income	21,964	25,866
Preferred stock dividends of subsidiaries	499	499
Net income for common stock	21,465	25,367
Bank
Revenues
Total revenues	72,856	68,840
Expenses
Other	48,696	49,246
Operating income (loss)
Total operating income	24,160	19,594
Income before income taxes	24,160	19,594
Income taxes	8,347	6,921
Net income	15,813	12,673
Preferred stock dividends of subsidiaries	0	0
Net income for common stock	15,813	12,673
Other
Revenues
Total revenues	95	68
Expenses
Other	5,331	6,137
Operating income (loss)
Total operating income	(5,236)	(6,069)
Income before income taxes	(7,300)	(8,887)
Income taxes	(4,189)	(3,173)
Net income	(3,111)	(5,714)
Preferred stock dividends of subsidiaries	(26)	(26)
Net income for common stock	$ (3,085)	$ (5,688)