Derivatives (Tables)

3 Months Ended

Mar. 31, 2017

Derivative Instruments, Gain (Loss) [Line Items]

Schedule of Derivative Assets and Liabilities at Fair Value

The following table provides the fair values of our derivative financial instruments for the periods presented:

	Asset Derivatives:
(dollars in thousands)	March 31, 2017			December 31, 2016
Derivatives designated as hedging instruments under FASB ASC 815:	Balance Sheet Location	Fair Value		Balance Sheet Location	Fair Value
Natural gas contracts	Prepaid and other current assets	$	239	Prepaid and other current assets	$	702
Natural gas contracts	Other assets	—		Other assets	45
Interest rate contract	Other assets	131		Other assets	—
Total designated		370			747
Derivatives not designated as hedging instruments under FASB ASC 815:
Natural gas contracts	Prepaid and other current assets	230		Prepaid and other current assets	732
Natural gas contracts	Other assets	—		Other assets	29
Total undesignated		230			761
Total		$	600		$	1,508
	Liability Derivatives:
(dollars in thousands)	March 31, 2017			December 31, 2016
Derivatives designated as hedging instruments under FASB ASC 815:	Balance Sheet Location	Fair Value		Balance Sheet Location	Fair Value
Natural gas contracts	Other long-term liabilities	$	29	Other long-term liabilities	$	—
Interest rate contract	Derivative liability - current	1,377		Derivative liability - current	1,928
Interest rate contract	Other long-term liabilities	—		Other long-term liabilities	107
Total designated		1,406			2,035
Derivatives not designated as hedging instruments under FASB ASC 815:
Natural gas contracts	Other long-term liabilities	52		Other long-term liabilities	—
Total undesignated		52			—
Total		$	1,458		$	2,035

Summary of the Effective Portion of Derivative Gain (Loss) Recognized in Other Comprehensive Income (Loss)

The following table provides a summary of the effective portion of derivative gain (loss) recognized in other comprehensive income (loss) from our interest rate swap:

	Three months ended March 31,
(dollars in thousands)	2017		2016
Derivatives in Cash Flow Hedging relationships:
Interest rate swap	$	204	$	(3,219	)
Total	$	204	$	(3,219	)

The following table provides a summary of the effective portion of derivative gain (loss) recognized in other comprehensive income (loss) from our natural gas contracts:

	Three months ended March 31,
(dollars in thousands)	2017			2016
Derivatives in Cash Flow Hedging relationships:
Natural gas contracts	$	(470	)	$	(616	)
Total	$	(470	)	$	(616	)

Reclassification out of Accumulated Other Comprehensive Income

The following table provides a summary of the effective portion of derivative reclassified from accumulated other comprehensive income to the Condensed Consolidated Statements of Operations from our interest rate swap:

		Three months ended March 31,
(dollars in thousands)		2017			2016
Derivative:	Location:
Interest rate swap	Interest expense	$	(585	)	$	(391	)
Total impact on net income (loss)		$	(585	)	$	(391	)

The following table provides a summary of the effective portion of derivative reclassified from accumulated other comprehensive loss to the Condensed Consolidated Statements of Operations from our natural gas contracts:

		Three months ended March 31,
(dollars in thousands)		2017		2016
Derivative:	Location:
Natural gas contracts	Cost of sales	$	67	$	(540	)
Total impact on net income (loss)		$	67	$	(540	)

Summary of Derivatives Not Designated as Hedging Instruments Recognized in the Statement of Operations

Gains (losses) on currency derivatives that were not designated as hedging instruments are recorded in other income (expense) as follows:

		Three months ended March 31,
(dollars in thousands)		2017		2016
Derivative:	Location:
Currency contracts	Other income (expense)	$	—	$	(418	)
Total		$	—	$	(418	)

Natural Gas Contracts

Derivative Instruments, Gain (Loss) [Line Items]

Summary of the Gain (Loss) Recognized in the Statement of Operations

The following table provides a summary of the gain (loss) recognized in other income (expense) in the Condensed Consolidated Statements of Operations from our natural gas contracts in Mexico:

	Three months ended March 31,
(dollars in thousands)	2017			2016
Contracts where hedge accounting was not elected	$	(583	)	$	370
Total	$	(583	)	$	370