Variation of Provision for Income Taxes from Statutory U.S. Federal Income Tax Rate (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Statutory Tax Rate	35.00%
Income taxes computed at the statutory U.S. federal income tax rate	$ 99,597	$ 89,151	$ 78,325
State income taxes, net of federal tax benefit	8,165	7,775	5,978
Tax liabilities required (no longer required)	815	(17,043)	(182)
Valuation allowance	(3,747)	(5,087)	239
Manufacturing exemption	(5,798)	(7,452)	(6,865)
Tax credit refunds, net	(2,163)	(1,797)	(1,066)
Foreign earnings taxed at other than 35%	5,957	(600)	(566)
Deferred tax rate changes	(1,327)	2,235	(3,422)
Other	662	2,123	0
Provision for income taxes	$ 102,161	$ 69,305	$ 72,441
Effective tax rate	35.90%	27.20%	32.40%