Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2011

Quarterly Financial Data (Unaudited)

Schedule of Quarterly Financial Data (Unaudited)

	Year Ended December 31, 2011
	First Quarter			Second Quarter		Third Quarter		Fourth Quarter			Year
Operating revenues (000)	$	865,951		$	933,697	$	955,425	$	899,850		$	3,654,923
Operating income (loss) (000)		227			19,040		26,827		(4,988	)		41,106
Net income (loss) (000)		(11,063	)		1,579		116		(17,967	)		(27,335	)
Net income (loss) per common share:
Basic		(0.21	)		0.03		0.00		(0.35	)		(0.52	)
Diluted		(0.21	)		0.03		0.00		(0.35	)		(0.52	)
Weighted average common shares:
Basic:		53,844			52,698		51,570		50,691			52,201
Diluted:		53,844			53,371		52,315		50,691			52,201

	Year Ended December 31, 2010
	First Quarter		Second Quarter		Third Quarter		Fourth Quarter		Year
Operating revenues (000)	$	632,243	$	649,759	$	686,858	$	796,285	$	2,765,145
Operating income (000)		42,421		49,288		58,282		51,835		201,826
Net income (000)		15,014		18,655		25,474		37,207		96,350
Net income per common share:
Basic	$	0.27		0.33		0.46		0.68		1.73
Diluted		0.26		0.33		0.45		0.67		1.70
Weighted average common shares:
Basic:		55,855		55,936		55,901		54,747		55,610
Diluted:		56,864		56,718		56,804		55,719		56,526