Derivative Contracts (Tables)

6 Months Ended

Jun. 30, 2013

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Effects of Derivative Contracts in Condensed Consolidated Financial Statements

The following tables summarize the gross amounts of recognized derivative assets and liabilities, the net amounts presented in the consolidated balance sheet, and the net amounts after deducting collateral that has been deposited with counterparties:

	As of June 30, 2013
								Amounts Not Offset in the Consolidated Balance Sheet
	Gross Amounts of Recognized Assets		Gross Amounts Offset in Consolidated Balance Sheet			Net Amounts of Assets Presented in Consolidated Balance Sheet		Financial Instruments		Cash Collateral Received		Net Amount
Open metal contracts	$	1,953	$	(1,574	)	$	379	$	—	$	—	$	379
(334 contracts)
Open electricity contracts		79		—			79		—		—		79
(6 contracts)
Interest rate cap agreements		—		—			—		—		—		—
(2 contracts)
Total	$	2,032	$	(1,574	)	$	458	$	—	$	—	$	458
Consolidated balance sheet location:
Prepaid expenses and other current assets			$	458
Total			$	458
								Amounts Not Offset in the Consolidated Balance Sheet
	Gross Amounts of Recognized Liabilities		Gross Amounts Offset in Consolidated Balance Sheet			Net Amounts of Liabilities Presented in Consolidated Balance Sheet		Financial Instruments		Cash Collateral Deposited		Net Amount
Open metal contracts	$	1,574	$	(1,574	)	$	—	$	—	$	—	$	—
(218 contracts)
Total	$	1,574	$	(1,574	)	$	—	$	—	$	—	$	—

	As of December 31, 2012
								Amounts Not Offset in the Consolidated Balance Sheet
	Gross Amounts of Recognized Assets		Gross Amounts Offset in Consolidated Balance Sheet			Net Amounts of Assets Presented in Consolidated Balance Sheet		Financial Instruments		Cash Collateral Received		Net Amount
Open metals contracts	$	603	$	(224	)	$	379	$	—	$	—	$	379
(208 contracts)
Open natural gas contracts		2		—			2		—		—		2
(6 contracts)
Open electricity contracts		169		(2	)		167		—		—		167
(17 contracts)
Interest rate cap agreements		1		—			1		—		—		1
(2 contracts)
Total	$	775	$	(226	)	$	549	$	—	$	—	$	549
Consolidated balance sheet location:
Prepaid expenses and other current assets			$	548
Other noncurrent assets				1
Total			$	549
								Amounts Not Offset in the Consolidated Balance Sheet
	Gross Amounts of Recognized Liabilities		Gross Amounts Offset in Consolidated Balance Sheet			Net Amounts of Liabilities Presented in Consolidated Balance Sheet		Financial Instruments		Cash Collateral Deposited		Net Amount
Open metals contracts	$	224	$	(224	)	$	—	$	—	$	—	$	—
(85 contracts)
Open electricity contracts		2		(2	)		—		—		—		—
(1 contract)
Total	$	226	$	(226	)	$	—	$	—	$	—	$	—

The following table summarizes the effects of derivative contracts in the consolidated statements of operations:

	Three Months Ended June 30,						Six Months Ended June 30,
	2013			2012			2013			2012
Cost of sales
Realized and unrealized gain (loss)—metal contracts	$	634		$	(606	)	$	651		$	504
Realized and unrealized gain (loss)—natural gas contracts		—			34			(2	)		69
Realized and unrealized (loss) gain—electricity contracts		(165	)		147			(85	)		(35	)
Total	$	469		$	(425	)	$	564		$	538
Interest expense
Unrealized loss—interest rate cap agreements	$	—		$	(12	)	$	(1	)	$	(146	)