Fair Value Measurements (Tables)
 3 Months Ended
Mar. 31, 2015
Fair Value Disclosures [Abstract]  
Assets Measured at Fair Value on a Recurring Basis, Categorized by the Level of Inputs Used in the Valuation
From time to time we enter into various instruments that require fair value measurement, including foreign currency option contracts, interest rate swaps and copper derivative contracts. Assets and liabilities measured on a recurring basis, categorized by the level of inputs used in the valuation, include:

(Dollars in thousands)
 
Carrying amount as of March 31, 2015
 
Level 1
 
Level 2
 
Level 3
Foreign currency contracts
 
473

 
—

 
473

 
—

Copper derivative contracts
 
290

 
—

 
290

 
—

Interest rate swap
 
(128
)
 
—

 
(128
)
 
—

(Dollars in thousands)
 
Carrying amount as of December 31, 2014
 
Level 1
 
Level 2
 
Level 3
Foreign currency contracts
 
(18
)
 
—

 
(18
)
 
—

Copper derivative contracts
 
355

 
—

 
355

 
—

Interest rate swap
 
(144
)
 
—

 
(144
)
 
—