Quarterly Financial Information (Unaudited)

12 Months Ended

Dec. 31, 2012

Quarterly Financial Information (Unaudited) [Abstract]

Quarterly Financial Information [Text Block]

Quarterly Financial Information (Unaudited)

	First		Second		Third		Fourth
	(In Thousands, Except Per Share Data)
Year ended December 31, 2012
Operating revenue	$	134,833	$	139,710	$	135,010	$	136,192
Operating income	23,778		26,748		19,667		24,708
Income before income taxes	23,920		26,915		19,858		24,882
Net income	16,588		18,227		12,434		14,292
Net income per share, basic	0.19		0.21		0.15		0.17
Net income per share, diluted	0.19		0.21		0.14		0.17
Year ended December 31, 2011
Operating revenue	$	127,692	$	137,192	$	132,529	$	131,210
Operating income	21,873		32,687		25,132		26,865
Income before income taxes	22,110		32,895		25,306		27,019
Net income	14,879		22,532		15,399		17,122
Net income per share, basic	0.16		0.25		0.17		0.20
Net income per share, diluted	0.16		0.25		0.17		0.20