Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2021

Fair Value Disclosures [Abstract]

Schedule of Available-for-sale Residual Pension Surplus Investment Balance

Available-for-sale investments measured at fair value on a recurring basis, categorized by the level of inputs used in the valuation, were as follows:

	Available-for-Sale Investment at Fair Value as of March 31, 2021
(Dollars in thousands)	Level 1		Level 2		Level 3		Total
Pension surplus investment(1)	$	6,417	$	2,389	$	—	$	8,806

	Available-for-Sale Investment at Fair Value as of December 31, 2020
(Dollars in thousands)	Level 1		Level 2		Level 3		Total
Pension surplus investment(1)	$	6,706	$	2,400	$	—	$	9,106

(1) This balance was invested in funds comprised of short-term cash and fixed income securities, and was recorded in the “Other long-term assets” line item in the condensed consolidated statements of financial position. As of March 31, 2021, the fair value of these investments approximated its carrying value.

Assets Measured at Fair Value on a Recurring Basis, Categorized by the Level of Inputs Used in the Valuation

Derivative instruments measured at fair value on a recurring basis, categorized by the level of inputs used in the valuation, were as follows:

	Derivative Instruments at Fair Value as of March 31, 2021
(Dollars in thousands)	Level 1		Level 2		Level 3		Total(1)
Foreign currency contracts	$	—	$	(58)	$	—	$	(58)
Copper derivative contracts	$	—	$	6,076	$	—	$	6,076

	Derivative Instruments at Fair Value as of December 31, 2020
(Dollars in thousands)	Level 1		Level 2		Level 3		Total(1)
Foreign currency contracts	$	—	$	(130)	$	—	$	(130)
Copper derivative contracts	$	—	$	4,785	$	—	$	4,785

(1) All balances were recorded in the “Other current assets” or “Other accrued liabilities” line items in the condensed consolidated statements of financial position.