Fair Value (Tables)

3 Months Ended

Mar. 31, 2014

Fair Value Disclosures [Abstract]

Fair Value Measurements, Recurring and Nonrecurring [Table Text Block]

	Fair Value at										Fair Value at
Asset / (Liability) (dollars in thousands)	March 31, 2014										December 31, 2013
	Level 1		Level 2			Level 3		Total			Level 1		Level 2			Level 3		Total
Commodity futures natural gas contracts	$	—	$	578		$	—	$	578		$	—	$	413		$	—	$	413
Currency contracts	—		—			—		—			—		—			—		—
Interest rate agreement	—		(1,644		)	—		(1,644		)	—		(2,073		)	—		(2,073		)
Net derivative asset (liability)	$	—	$	(1,066	)	$	—	$	(1,066	)	$	—	$	(1,660	)	$	—	$	(1,660	)

Fair Value, by Balance Sheet Grouping [Table Text Block]

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

Asset / (Liability) (dollars in thousands)	March 31, 2014			December 31, 2013
Prepaid and other current assets	$	573		$	394
Other assets	5			19
Derivative liability	(1,644		)	—
Other long-term liabilities	—			(2,073		)
Net derivative asset (liability)	$	(1,066	)	$	(1,660	)