Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2011

QUARTERLY FINANCIAL DATA (unaudited): [Abstract]

Schedule of Quarterly Financial Information [Table Text Block]

Quarterly Results

(dollars in thousands, except per share data)

	First Quarter			Second Quarter			Third Quarter			Fourth Quarter
2011
Operating revenues	$	191,911		$	209,589		$	217,210		$	210,386
Income from operations	39,203			51,165			56,023			45,388
Income from continuing operations, net of tax	22,122			31,145			32,952			33,274
(Loss)/income from discontinued operations, net of tax	—			—			(10		)	1
Net income	22,122			31,145			32,942			33,275
Diluted earnings per common share from continuing operations	$	0.52		$	0.73		$	0.77		$	0.77
Diluted earnings per common share from discontinued operations	—			—			—			—
Diluted earnings per common share	$	0.52		$	0.73		$	0.77		$	0.77
2010
Operating revenues	$	145,579		$	158,453		$	156,492		$	169,671
Income from operations	30,106			37,873			38,512			23,919
Income from continuing operations, net of tax	15,976			20,691			22,050			19,952
(Loss)/income from discontinued operations, net of tax	(16		)	(56		)	2,745			(82		)
Net income	15,960			20,635			24,795			19,870
Diluted earnings per common share from continuing operations	$	0.39		$	0.50		$	0.53		$	0.47
Diluted earnings per common share from discontinued operations	—			—			0.07			—
Diluted earnings per common share	$	0.39		$	0.49		$	0.59		$	0.47