SUMMARIZED QUARTERLY FINANCIAL INFORMATION - UNAUDITED (Tables)

12 Months Ended

Dec. 31, 2012

Results of Operations By Quarter

The results of operations by quarter are as follows:

	2012 Quarter Ended
	March 31		June 30		September 30		December 31
Operating revenue	$	244,957	$	226,561	$	227,397	$	254,871
Income from operations		84,927		56,156		44,485		78,397
Net income		50,974		30,547		23,659		44,246
Basic earnings per share	$	1.03	$	0.62	$	0.48	$	0.89
Diluted earnings per share	$	1.03	$	0.62	$	0.48	$	0.89

	2011 Quarter Ended
	March 31		June 30		September 30		December 31
Operating revenue	$	200,039	$	235,734	$	214,594	$	223,616
Income from operations		64,752		92,155		80,694		73,399
Net income		39,792		57,196		51,821		45,523
Basic earnings per share	$	0.81	$	1.17	$	1.06	$	0.93
Diluted earnings per share	$	0.81	$	1.17	$	1.06	$	0.93