Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Operating revenues:
Electric	$ 131,822	$ 126,282	$ 266,185	$ 268,924	$ 552,347	$ 567,559
Gas	5,641	6,279	20,754	26,096	36,360	46,341
Other	1,857	1,996	3,696	4,081	8,400	8,076
Total operating revenues	139,320	134,557	290,635	299,101	597,107	621,976
Operating revenue deductions:
Fuel and purchased power	37,505	39,153	75,345	88,131	157,075	193,273
Cost of natural gas sold and transported	1,478	2,041	9,039	13,464	15,076	22,767
Regulated operating expenses	27,485	27,669	55,329	56,219	112,661	111,430
Other operating expenses	854	789	1,815	1,594	3,530	3,083
Maintenance and repairs	12,712	15,583	22,931	25,850	45,603	50,975
Merger related expenses	4,192		8,440		8,440
Depreciation and amortization	20,817	20,127	41,221	40,147	81,624	77,234
Provision for income taxes	5,792	4,056	14,467	12,939	36,328	33,469
Other taxes	9,108	9,092	19,428	19,996	38,611	37,975
Total operating revenue deductions	119,943	118,510	248,015	258,340	498,948	530,206
Operating income	19,377	16,047	42,620	40,761	98,159	91,770
Other income and (deductions):
Allowance for equity funds used during construction	1,062	1,234	2,766	2,212	5,405	5,859
Interest income	44	129	53	140	58	147
Benefit for other income taxes	117	14	153	127	1,014	206
Other - non-operating expense, net	(361)	(225)	(769)	(924)	(3,274)	(1,581)
Total other income	862	1,152	2,203	1,555	3,203	4,631
Interest charges:
Long-term debt	11,298	10,752	22,596	21,503	44,895	41,929
Short-term debt	26	95	88	168	186	263
Allowance for borrowed funds used during construction	(616)	(723)	(1,669)	(1,287)	(3,226)	(3,214)
Other	306	305	574	525	1,083	1,012
Total interest charges	11,014	10,429	21,589	20,909	42,938	39,990
Net income	$ 9,225	$ 6,770	$ 23,234	$ 21,407	$ 58,424	$ 56,411
Weighted average number of common shares outstanding - basic (in shares)	43,953	43,627	43,918	43,579	43,839	43,492
Weighted average number of common shares outstanding - diluted (in shares)	44,006	43,712	43,963	43,669	43,866	43,579
Total earnings per weighted average share of common stock - basic and diluted (in dollars per share)			$ 0.53	$ 0.49
Total earnings per weighted average share of common stock - basic (in dollars per share)	$ 0.21	$ 0.16			$ 1.33	$ 1.30
Total earnings per weighted average share of common stock - diluted (in dollars per share	0.21	0.15			1.33	1.29
Dividends declared per share of common stock (in dollars per share)	$ 0.26	$ 0.26	$ 0.52	$ 0.52	$ 1.04	$ 1.035