Segment Information (Tables)

9 Months Ended

Sep. 30, 2011

Segment Information [Abstract]

Company's Segment Information, Revenues

	Three Months Ended			Three Months Ended
	September 30, 2011			September 30, 2010
	Regulated	Other	Consolidated	Regulated	Other	Consolidated
Operating revenues	$ 194,068	$     3,260	$   197,328	$      190,656	$     2,821	$      193,477
Operations and
maintenance expense	69,016	1,023	70,039	66,014	2,894	68,908
Depreciation	27,461	(329)	27,132	26,706	(212)	26,494
Operating income (loss)	85,573	2,186	87,759	83,436	(113)	83,323
Interest expense,
net of AFUDC	16,668	1,088	17,756	16,210	1,346	17,556
Income tax	24,396	307	24,703	26,798	(1,070)	25,728
Income (loss) from continuing operations	44,589	927	45,516	40,692	(362)	40,330
	Nine Months Ended			Nine Months Ended
	September 30, 2011			September 30, 2010
	Regulated	Other	Consolidated	Regulated	Other	Consolidated
Operating revenues	$529,764	$     9,492	$   539,256	$      506,820	$     8,183	$      515,003
Operations and
maintenance expense	196,033	4,502	200,535	191,224	7,224	198,448
Depreciation	81,069	(1,185)	79,884	78,629	(994)	77,635
Operating income	216,584	4,792	221,376	196,758	757	197,515
Interest expense,
net of AFUDC	49,489	3,258	52,747	47,810	2,713	50,523
Gain on sale of other assets	178	297	475	221	2,073	2,294
Income tax	55,985	318	56,303	59,996	(1,423)	58,573
Income from continuing operations	111,288	1,513	112,801	89,173	1,540	90,713
Capital expenditures	225,007	1,068	226,075	231,216	326	231,542

Company's Segment Information, Assets

	September 30,	December 31,
	2011	2010
Total assets:
Regulated	$    4,142,219	$  3,991,493
Other and eliminations	85,850	80,973
Consolidated	$    4,228,069	$  4,072,466