Derivative Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2019

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, 2019 and December 31, 2018:

	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
Embedded derivative liability		—		—		—		3,916
Total derivative financial instruments	$	9,145	$	12,828	$	4,357	$	8,268

	December 31, 2018
	Other Current Assets		Other Non-current Assets		Accrued Liabilities		Other Non-current Liabilities
(Dollars in thousands)
Foreign exchange forward contracts designated as    hedging instruments	$	2,599	$	1,011	$	659	$	6,202
Foreign exchange forward contracts not    designated as hedging instruments		333		—		207		—
Aluminum forward contracts designated as    hedging instruments		—		—		927		—
Cross currency swap not designated as hedging    instrument		—		—		227		—
Natural gas forward contracts designated as    hedging instruments		275		—		355		—
Interest rate swap contracts designated as hedging    instruments		—		—		131		128
Embedded derivative liability		—		—		—		3,134
Total derivative financial instruments	$	3,207	$	1,011	$	2,506	$	9,464

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, 2019					December 31, 2018
	Notional U.S. Dollar Amount		Fair Value			Notional U.S. Dollar Amount		Fair Value
(Dollars in thousands)
Foreign currency forward contracts and collars    designated as hedging instruments	$	449,181	$	20,469		$	467,253	$	(3,251	)
Foreign exchange forward contracts not designated    as hedging instruments		73,491		642			45,905		126
Aluminum forward contracts designated as    hedging instruments		9,405		(67	)		10,810		(927	)
Cross currency swap not designated as hedging    instrument		—		—			12,151		(227	)
Natural gas forward contracts designated as hedging    instruments		5,816		(1,951	)		2,165		(80	)
Interest rate swap contracts designated as hedging    instruments		260,000		(5,829	)		90,000		(259	)
Total derivative financial instruments	$	797,893	$	13,264		$	628,284	$	(4,618	)

Summary of Gain or Loss Recognized in AOCI (Loss)

The following tables summarize the gain or loss recognized in AOCI as of December 31, 2019, 2018 and 2017, the amounts reclassified from AOCI into earnings and the amounts recognized directly into earnings for the years ended December 31, 2019, 2018 and 2017:

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

Year ended December 31, 2018	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	$	5,293	$	728	$	(406	)
Total	$	5,293	$	728	$	(406	)

Year ended December 31, 2017	Amount of Gain or (Loss) Recognized in AOCI on Derivatives (Effective Portion)		Amount of Pre-tax Gain or (Loss) Reclassified from AOCI into Income (Effective Portion)			Amount of Pre-tax Gain or (Loss) Recognized in Income on Derivatives (Ineffective Portion and Amount Excluded from Effectiveness Testing)
(Dollars in thousands)
Derivative Contracts	$	7,603	$	(4,539	)	$	(538	)
Total	$	7,603	$	(4,539	)	$	(538	)