Fair Value (Tables)

12 Months Ended

Dec. 31, 2014

Fair Value Disclosures [Abstract]

Fair Value of Derivatives

	Fair Value at										Fair Value at
Asset / (Liability (dollars in thousands)	December 31, 2014										December 31, 2013
	Level 1		Level 2			Level 3		Total			Level 1		Level 2			Level 3		Total
Commodity futures natural gas contracts	$	—	$	(2,868	)	$	—	$	(2,868	)	$	—	$	413		$	—	$	413
Currency contracts	—		403			—		403			—		—			—		—
Interest rate agreements	—		—			—		—			—		(2,073		)	—		(2,073		)
Net derivative asset (liability)	$	—	$	(2,465	)	$	—	$	(2,465	)	$	—	$	(1,660	)	$	—	$	(1,660	)

Total Derivative Position Recorded on Balance Sheet

The total derivative position is recorded on the Consolidated Balance Sheets as follows:

Asset / (Liability (dollars in thousands)	December 31, 2014			December 31, 2013
Prepaid and other current assets	$	403		$	394
Other assets	—			19
Derivative liability	(2,653		)	—
Other long-term liabilities	(215		)	(2,073		)
Net derivative asset (liability)	$	(2,465	)	$	(1,660	)