Note 12 - Selected Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2012

Dec. 31, 2011

Schedule of Quarterly Financial Information [Table Text Block]

	Fiscal Quarter
	First		Second		Third		Fourth
	(In thousands, except for per share data)
Year Ended December 31, 2012:
Operating revenue	$	80,674	$	94,691	$	102,879	$	126,587
Operating income		20,821		33,046		41,063		58,511
Net income (loss)		3,371		10,994		15,873		(2,109	)
Net income (loss) available to common stockholders		2,192		9,815		14,640		(2,613	)
Basic net income (loss) available to common stockholders per share	$	0.04	$	0.17	$	0.26	$	(0.05	)
Diluted net income (loss) available to common stockholders per share	$	0.04	$	0.17	$	0.26	$	(0.05	)

Year Ended December 31, 2011:
Operating revenue	$	69,742		$	76,201	$	76,518	$	84,670
Operating income		11,506			19,028		18,222		26,592
Net income (loss)		(3,083	)		2,559		1,984		7,575
Net income (loss) available to common stockholders		(4,872	)		771		27		5,869
Basic net (loss) income available to common stockholders per share	$	(0.09	)	$	0.01	$	-	$	0.10
Diluted net (loss) income available to common stockholders per share	$	(0.09	)	$	0.01	$	-	$	0.10