Reconciliation of Federal Statutory Income Tax Rate to Effective Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule Of Effective Tax Rates Line Items
Federal statutory rate	35.00%	35.00%	35.00%
State income taxes, net of federal benefit	1.80%	1.80%	1.80%
Domestic manufacturing deduction	(1.50%)	(1.90%)	(1.80%)
Research tax credit	0.00%	(0.80%)	(1.20%)
Valuation allowance for foreign subsidiaries net operating losses	0.00%	0.50%	0.40%
Other permanent differences	(0.40%)	(0.30%)	(1.50%)
Effective income tax rate	34.90%	34.30%	32.70%