Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2016

Fair Value Disclosures [Abstract]

Assets measured at fair value on a recurring basis, categorized by the level of inputs used in the valuation

Assets measured at fair value on a recurring basis, categorized by the level of inputs used in the valuation, include:

(Dollars in thousands)	As of December 31, 2016			Level 1		Level 2			Level 3
Foreign currency contracts	$	(170	)	$	—	$	(170	)	$	—
Copper derivative contracts	$	1,277		$	—	$	1,277		$	—
Interest rate swap	$	—		$	—	$	—		$	—

(Dollars in thousands)	As of December 31, 2015			Level 1		Level 2			Level 3
Foreign currency contracts	$	(78	)	$	—	$	(78	)	$	—
Copper derivative contracts	$	193		$	—	$	193		$	—
Interest rate swap	$	(18	)	$	—	$	(18	)	$	—