CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
Operating revenues:
Electric	$ 153,089	$ 128,762	$ 560,740	$ 519,690
Gas	24,609	20,493	54,157	44,659
Other	1,975	1,885	7,966	6,745
Total operating revenues	179,673	151,140	622,863	571,094
Operating revenue deductions:
Fuel and purchased power	55,586	45,303	185,690	178,971
Cost of natural gas sold and transported	15,045	11,925	28,914	21,977
Regulated operating expenses	27,957	27,137	106,153	98,160
Other operating expenses	716	794	3,064	2,926
Maintenance and repairs	10,257	9,157	41,973	40,476
Loss on plant disallowance		2,409		2,409
Depreciation and amortization	17,940	16,100	71,146	61,612
Provision for income taxes	12,174	7,454	42,185	35,466
Other taxes	10,510	9,003	36,445	31,828
Total operating revenue deductions	150,185	129,282	515,570	473,825
Operating income	29,488	21,858	107,293	97,269
Other income and (deductions):
Allowance for equity funds used during construction	1,252	526	4,579	1,623
Interest income	41	508	100	1,300
Benefit/(provision) for other income taxes	53	(28)	54	25
Other - non-operating expense, net	(345)	(289)	(1,273)	(1,973)
Total other income and (deductions)	1,001	717	3,460	975
Interest charges:
Long-term debt	10,105	9,951	40,509	39,488
Short-term debt	5	47	17	205
Allowance for borrowed funds used during construction	(741)	(305)	(2,522)	(1,038)
Other	215	252	1,028	1,083
Total interest charges	9,584	9,945	39,032	39,738
Net income	$ 20,905	$ 12,630	$ 71,721	$ 58,506
Weighted average number of common shares outstanding - basic (in shares)	43,111	42,564	42,916	42,385
Weighted average number of common shares outstanding - diluted (in shares)	43,144	42,587	42,936	42,401
Total earnings per weighted average share of common stock - basic and diluted (in dollars per share)	$ 0.48	$ 0.30	$ 1.67	$ 1.38
Dividends declared per share of common stock (in dollars per share)	$ 0.255	$ 0.250	$ 1.01	$ 1.00