Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Taxes [Line Items]
Bonus depreciation percentage for qualified investments	50.00%	100.00%
Refundable income taxes	$ 4,800,000
Deferred tax asset related to federal NOL carry forwards	4,640,000	4,498,000
Deferred tax credit benefits recognized	12,635,000	10,072,000	730,000
Federal Deferred provision (benefit)	13,143,000	9,897,000	568,000
Refundable income taxes	1,594,000	4,844,000
Federal NOL carryforwards	38,000,000
Research And Development Tax Credit
Income Taxes [Line Items]
Federal Deferred provision (benefit)	(1,300,000)
Refundable income taxes	615,000
Tax credits carried forward	726,000
Tax credits carried forward, expiration year	2032
Dunkirk Specialty Steel
Income Taxes [Line Items]
Deferred tax credit benefits recognized	65,000	125,000	43,000
Deferred tax credit benefits recognition period	15 years
Internal Revenue Service (IRS)
Income Taxes [Line Items]
Deferred tax asset related to federal NOL carry forwards		15,100,000
Federal income tax paid			$ 5,200,000