Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Revenues
Regulated Energy	$ 305,689	$ 301,902	$ 300,442
Unregulated Energy	203,778	162,108	184,961
Other businesses and eliminations	(10,607)	(4,766)	13,431
Total operating revenues	498,860	459,244	498,834
Operating Expenses
Regulated energy cost of sales	109,609	122,814	134,560
Unregulated energy and other cost of sales	128,434	97,228	143,556
Operations	117,571	107,562	102,197
Maintenance	12,391	11,803	9,706
(Gain from a settlement)/asset impairment charges	(130)	(1,500)	6,881
Depreciation and amortization	32,159	29,972	26,316
Other taxes	14,730	13,607	13,339
Total operating expenses	414,764	381,486	436,555
Operating Income	84,096	77,758	62,279
Gains from sales of businesses	0	0	7,139
Other (expense) income	(441)	293	101
Interest charges	10,639	10,006	9,482
Income Before Income Taxes	73,016	68,045	60,037
Income taxes	28,341	26,905	23,945
Net Income	$ 44,675	$ 41,140	$ 36,092
Weighted Average Common Shares Outstanding:
Basic (in shares)	15,570,539	15,094,423	14,551,308
Diluted (in shares)	15,613,091	15,143,373	14,604,944
Earnings Per Share of Common Stock:
Basic (in usd per share)	$ 2.87	$ 2.73	$ 2.48
Diluted (in usd per share)	2.86	2.72	2.47
Cash Dividends Declared Per Share of Common Stock (in usd per share)	$ 1.2025	$ 1.1325	$ 1.0667