Segment Information (Tables)

9 Months Ended

Sep. 30, 2013

Segment Information [Abstract]

Company's Segment Information, Continuing Operations

	Three Months Ended						Three Months Ended
	September 30, 2013						September 30, 2012
	Regulated		Other		Consolidated		Regulated		Other		Consolidated
Operating revenues	$	199,882	$	4,463	$	204,345	$	209,674	$	4,891	$	214,565
Operations and maintenance expense		68,470		3,595		72,065		68,351		2,917		71,268
Depreciation		30,081		107		30,188		28,764		(513)		28,251
Operating income		87,117		263		87,380		98,503		2,032		100,535
Interest expense, net of AFUDC		17,450		1,474		18,924		16,915		1,763		18,678
Income tax expense (benefit)		5,740		(552)		5,188		32,682		(107)		32,575
Income (loss) from continuing operations		64,010		(526)		63,484		48,971		1,313		50,284
	Nine Months Ended						Nine Months Ended
	September 30, 2013						September 30, 2012
	Regulated		Other		Consolidated		Regulated		Other		Consolidated
Operating revenues	$	567,255	$	12,780	$	580,035	$	556,847	$	13,432	$	570,279
Operations and maintenance expense		202,909		8,325		211,234		190,276		9,388		199,664
Depreciation		89,200		(229)		88,971		83,772		(1,036)		82,736
Operating income		232,771		2,835		235,606		245,871		3,535		249,406
Interest expense, net of AFUDC		51,746		4,620		56,366		50,401		4,499		54,900
Income tax expense (benefit)		21,023		(1,657)		19,366		78,652		(1,342)		77,310
Income (loss) from continuing operations		160,167		(1,904)		158,263		117,133		1,820		118,953
Capital expenditures		215,230		832		216,062		262,104		728		262,832

Company's Segment Information, Assets

	September 30,		December 31,
	2013		2012
Total assets:
Regulated	$	4,858,111	$	4,566,327
Other and eliminations		215,987		292,190
Consolidated	$	5,074,098	$	4,858,517