Fair Value (Tables)

6 Months Ended

Jun. 30, 2013

Fair Value Disclosures [Abstract]

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

	Fair Value at										Fair Value at
Asset / (Liability) (dollars in thousands)	June 30, 2013										December 31, 2012
	Level 1		Level 2			Level 3		Total			Level 1		Level 2			Level 3		Total
Commodity futures natural gas contracts	$	—	$	(112	)	$	—	$	(112	)	$	—	$	(420	)	$	—	$	(420	)
Currency contracts	—		458			—		458			—		41			—		41
Interest rate agreement	—		(1,781		)	—		(1,781		)	—		298			—		298
Net derivative asset (liability)	$	—	$	(1,435	)	$	—	$	(1,435	)	$	—	$	(81	)	$	—	$	(81	)

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)	June 30, 2013			December 31, 2012
Prepaid and other current assets	$	458		$	41
Derivative asset	—			298
Derivative liability	(69		)	(420		)
Other long-term liabilities	(1,824		)	—
Net derivative asset (liability)	$	(1,435	)	$	(81	)