Derivative Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2020

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Summary of Fair Value of Derivatives by Balance Sheet Line Item

The following tables display the fair value of derivatives by balance sheet line item at December 31, 2020 and December 31, 2019:

	December 31, 2020
	Other Current Assets		Other Non-current Assets		Accrued Liabilities		Other Non-current Liabilities
(Dollars in thousands)
Foreign exchange forward contracts designated as    hedging instruments	$	1,218	$	6,531	$	3,435	$	2,645
Foreign exchange forward contracts not    designated as hedging instruments		1,167		—		122		—
Aluminum forward contracts designated as    hedging instruments		262		—		—		—
Natural gas forward contracts designated as    hedging instruments		816		224		22		70
Interest rate swap contracts designated as hedging    instruments		—		—		4,771		4,194
Total derivative financial instruments	$	3,463	$	6,755	$	8,350	$	6,909

	December 31, 2019
	Other Current Assets		Other Non-current Assets		Accrued Liabilities		Other Non-current Liabilities
(Dollars in thousands)
Foreign exchange forward contracts designated as    hedging instruments	$	7,808	$	12,821	$	60	$	100
Foreign exchange forward contracts not    designated as hedging instruments		1,196		—		554		—
Aluminum forward contracts designated as    hedging instruments		60		—		127		—
Natural gas forward contracts designated as    hedging instruments		81		7		1,312		727
Interest rate swap contracts designated as hedging    instruments		—		—		2,304		3,525
Total derivative financial instruments	$	9,145	$	12,828	$	4,357	$	4,352

Summary of Notional Amount and Estimated Fair Value of Derivative Financial Instruments

The following table summarizes the notional amount and estimated fair value of our derivative financial instruments:

	December 31, 2020					December 31, 2019
	Notional U.S. Dollar Amount		Fair Value			Notional U.S. Dollar Amount		Fair Value
(Dollars in thousands)
Foreign exchange forward contracts designated as    hedging instruments	$	421,253	$	1,669		$	449,181	$	20,469
Foreign exchange forward contracts not designated    as hedging instruments		71,217		1,045			73,491		642
Aluminum forward contracts designated as    hedging instruments		4,068		262			9,405		(67	)
Natural gas forward contracts designated as hedging    instruments		5,523		948			5,816		(1,951	)
Interest rate swap contracts designated as hedging    instruments		200,000		(8,965	)		260,000		(5,829	)
Total derivative financial instruments	$	702,061	$	(5,041	)	$	797,893	$	13,264

Summary of Gain or Loss Recognized in Accumulated Other Comprehensive Income or Loss

The following tables summarize the gain or loss recognized in accumulated other comprehensive income or loss (“AOCI”) for the years ended December 31, 2020 and 2019, the amounts reclassified from AOCI into earnings and the amounts recognized directly into earnings for the years ended December 31, 2020 and 2019:

Year Ended December 31, 2020	Amount of Gain or (Loss) Recognized in AOCI on Derivatives			Amount of Pre-tax Gain or (Loss) Reclassified from AOCI into Income			Amount of Pre-tax Gain or (Loss) Recognized in Income on Derivatives
(Dollars in thousands)
Derivative Contracts	$	(11,689	)	$	(8,365	)	$	2,098
Total	$	(11,689	)	$	(8,365	)	$	2,098

Year Ended December 31, 2019	Amount of Gain or (Loss) Recognized in AOCI on Derivatives		Amount of Pre-tax Gain or (Loss) Reclassified from AOCI into Income		Amount of Pre-tax Gain or (Loss) Recognized in Income on Derivatives
(Dollars in thousands)
Derivative Contracts	$	13,156	$	3,746	$	4,320
Total	$	13,156	$	3,746	$	4,320