Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Revenues
Regulated Energy	$ 345,281	$ 326,310	$ 305,689
Unregulated Energy	420,617	324,595	203,778
Other	(48,409)	(33,322)	(10,607)
Total operating revenues	717,489	617,583	498,860
Operating Expenses
Regulated Energy cost of sales	121,828	118,769	109,609
Unregulated Energy and other cost of sales	288,913	219,145	128,434
Operations	138,441	125,994	115,684
Cost, Maintenance	14,387	12,701	12,391
Gain from a settlement	(130)	(130)	(130)
Depreciation and amortization	40,802	36,599	32,159
Other taxes	18,628	17,085	14,730
Total operating expenses	622,869	530,163	412,877
Operating Income	94,620	87,420	85,983
Other expense, net	(615)	(2,342)	(2,328)
Interest charges	16,431	12,645	10,639
Income Before Income Taxes	77,574	72,433	73,016
Income taxes	20,994	14,309	28,341
Net Income	$ 56,580	$ 58,124	$ 44,675
Weighted Average Common Shares Outstanding:
Basic (in shares)	16,369,616	16,336,789	15,570,539
Diluted (in shares)	16,419,870	16,383,352	15,613,091
Earnings Per Share of Common Stock:
Basic (in usd per share)	$ 3.46	$ 3.56	$ 2.87
Diluted (in usd per share)	3.45	3.55	2.86
Cash Dividends Declared Per Share of Common Stock (in usd per share)	$ 1.4350	$ 1.2800	$ 1.2025