Quarterly Operations (Unaudited)

12 Months Ended

Dec. 31, 2011

Notes to Financial Statements [Abstract]

Quarterly Financial Information [Text Block]

16. Quarterly Operations (Unaudited)

The following table provides certain quarterly financial information for the periods presented.

		Quarters Ended
2011	March 31		June 30		September 30		December 31
	(In thousands)
Operating revenues	$	202,294	$	189,760	$	192,699	$	218,897
Operating income		91,016		87,705		82,024		101,680
Net earnings		45,612		40,219		35,425		47,399
		Quarters Ended
2010	March 31		June 30		September 30		December 31
	(In thousands)
Operating revenues	$	186,675	$	187,090	$	186,563	$	209,122
Operating income		80,509		80,811		76,642		101,159
Net earnings		33,592		33,753		31,512		48,798