Quarterly Results of Operations (Tables)

12 Months Ended

Dec. 31, 2012

Quarterly Financial Information Disclosure [Abstract]

Schedule Of Quarterly Results Of Operations

(In thousands, except per share amounts)	First Quarter		Second Quarter		Third Quarter		Fourth Quarter
2012:
Operating revenues	$	498,376	$	521,812	$	506,504	$	509,694
Operating income	35,402		51,113		41,805		43,124
Net income	21,245		30,680		25,128		25,981
Basic earnings per share	0.29		0.42		0.34		0.36
Diluted earnings per share	0.29		0.42		0.34		0.35

(In thousands, except per share amounts)	First Quarter		Second Quarter		Third Quarter		Fourth Quarter
2011:
Operating revenues	$	469,429	$	515,897	$	509,587	$	507,937
Operating income	27,442		46,767		50,066		49,399
Net income	16,293		27,518		29,578		29,368
Basic earnings per share	0.22		0.38		0.41		0.40
Diluted earnings per share	0.22		0.38		0.40		0.40