SEGMENTS OF BUSINESS (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Operating revenues	$ 122,592	$ 121,913	$ 378,222	$ 396,745
Operating income (loss)	(10,593)	10,257	41,386	83,765
Depreciation and amortization	17,256	14,188	31,664	27,463
Interest charges	3,420	5,195	8,128	10,688
Income taxes	(11,632)	(1,072)	(3,860)	14,812
Property additions	60,899	47,239	101,267	93,654
Indentifiable assets	2,654,497		2,654,497		2,631,440
Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	132,301	129,936	398,340	413,290
Interest charges	4,408	5,908	10,408	11,961
Operating Segments [Member] | Gas Utility Operations [Member]
Segment Reporting Information [Line Items]
Operating revenues	66,536	59,177	240,634	238,613
Operating income (loss)	8,069	7,465	65,864	66,320
Depreciation and amortization	12,929	11,130	23,953	22,092
Interest charges	2,789	3,771	5,750	7,960
Income taxes	2,269	1,887	23,040	22,864
Property additions	44,764	40,220	81,806	80,876
Indentifiable assets	1,834,645		1,834,645		1,786,459
Operating Segments [Member] | Wholesale Energy Operations [Member]
Segment Reporting Information [Line Items]
Operating revenues	(10,699)	(471)	(4,482)	17,171
Operating income (loss)	(19,200)	(2,843)	(24,357)	7,829
Depreciation and amortization	55	64	106	117
Interest charges	33	72	85	158
Income taxes	(7,710)	(1,028)	(9,691)	2,953
Property additions	25	8	34	12
Indentifiable assets	250,792		250,792		204,358
Operating Segments [Member] | Retail Energy Operations [Member]
Segment Reporting Information [Line Items]
Operating revenues	69,102	64,899	146,346	144,461
Operating income (loss)	570	5,621	(125)	9,634
Depreciation and amortization	4,051	2,823	7,159	4,919
Interest charges	374	1,228	1,853	2,285
Income taxes	(6,319)	(1,950)	(17,417)	(11,083)
Property additions	14,984	5,757	17,563	11,107
Indentifiable assets	536,031		536,031		608,060
Operating Segments [Member] | Retail Energy Operations [Member] | Retail Gas and Other Operations [Member]
Segment Reporting Information [Line Items]
Operating revenues	24,585	13,600	58,698	31,792
Operating income (loss)	(160)	(395)	(132)	(547)
Depreciation and amortization	21	23	43	31
Interest charges	67	13	143	51
Income taxes	(52)	(90)	220	94
Property additions	35	50	37	103
Indentifiable assets	32,152		32,152		39,481
Operating Segments [Member] | Retail Energy Operations [Member] | Retail Electric Operations [Member]
Segment Reporting Information [Line Items]
Operating revenues	31,419	38,365	62,148	88,552
Operating income (loss)	(337)	5,110	127	10,054
Income taxes	(139)	2,087	51	4,107
Indentifiable assets	28,528		28,528		21,919
Operating Segments [Member] | Retail Energy Operations [Member] | On-site Energy Production [Member]
Segment Reporting Information [Line Items]
Operating revenues	9,965	9,356	19,059	17,257
Operating income (loss)	268	684	(905)	346
Depreciation and amortization	3,958	2,722	6,970	4,726
Interest charges	307	1,215	1,710	2,234
Income taxes	(6,466)	(4,056)	(18,030)	(15,230)
Property additions	14,949	5,705	17,526	11,002
Indentifiable assets	472,603		472,603		543,416
Operating Segments [Member] | Retail Energy Operations [Member] | Appliance Service Operations [Member]
Segment Reporting Information [Line Items]
Operating revenues	3,133	3,578	6,441	6,860
Operating income (loss)	799	222	785	(219)
Depreciation and amortization	72	78	146	162
Income taxes	338	109	342	(54)
Property additions	0	2	0	2
Indentifiable assets	2,748		2,748		3,244
Operating Segments [Member] | Corporate and Services [Member]
Segment Reporting Information [Line Items]
Operating revenues	7,362	6,331	15,842	13,045
Operating income (loss)	(32)	14	4	(18)
Depreciation and amortization	221	171	446	335
Interest charges	1,212	837	2,720	1,558
Income taxes	128	19	208	78
Property additions	1,126	1,254	1,864	1,659
Indentifiable assets	295,085		295,085		337,010
Discontinued Operations [Member]
Segment Reporting Information [Line Items]
Indentifiable assets	1,886		1,886		78
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Operating revenues	(9,709)	(8,023)	(20,118)	(16,545)
Interest charges	(988)	(713)	(2,280)	(1,273)
Indentifiable assets	$ (263,942)		$ (263,942)		$ (304,525)