Quarterly Financial Information (Tables)

12 Months Ended

Dec. 31, 2013

Summary of Unaudited Quarterly Financial Information

	1st  Quarter		2nd  Quarter		3rd Quarter		4th Quarter
2012
Operating revenues	$	745,921	$	681,112	$	643,631	$	652,750
Operating income		157,664		150,894		88,594		100,209
Net income		97,274		92,538		50,806		58,859
Net income per common share:
Basic	$	0.62	$	0.60	$	0.34	$	0.40
Diluted	$	0.62	$	0.60	$	0.33	$	0.40
2013
Operating revenues	$	667,039	$	659,316	$	730,907	$	658,772
Operating income		94,932		70,606		124,551		32,102
Net income		56,230		40,768		74,420		16,591
Net income per common share:
Basic	$	0.38	$	0.28	$	0.51	$	0.12
Diluted	$	0.38	$	0.28	$	0.51	$	0.11