Income Tax (Tables)

9 Months Ended

Sep. 30, 2015

Income Tax Disclosure [Abstract]

Schedule of Components of Income Tax Expenses (Benefit)

	Three Months Ended September 30,						Nine Months Ended September 30,
Dollars in thousands	2015			2014			2015			2014
Income tax at statutory rates (federal and state)	$	(4,473	)	$	(6,161	)	$	15,848		$	20,288
Increase (decrease):
Differences required to be flowed-through by regulatory commissions	(378		)	(310		)	1,036			1,184
Other, net	298			(271		)	(940		)	(449		)
Income tax expense (benefit)	$	(4,553	)	$	(6,742	)	$	15,944		$	21,023
Effective income tax rate	40.5		%	43.6		%	39.9		%	41.0		%