Consolidated Statements Of Operations (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2011		Sep. 30, 2011		Jun. 30, 2011		Mar. 31, 2011		Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Income Statement [Abstract]
Net sales	$ 801,041		$ 821,175		$ 913,958		$ 1,034,867		$ 859,175		$ 968,372		$ 925,049		$ 867,252		$ 3,571,041	[1]	$ 3,619,848	[1]	$ 3,171,787	[1]
Cost of sales																	2,834,081		3,060,842		2,689,104
Gross profit	190,248		172,179		201,896		172,637		77,260		147,067		167,095		167,584		736,960		559,006		482,683
Selling, general and administrative expenses																	121,609		112,210		104,319
Income from operations	156,231		142,517		170,978		145,625		50,459		117,331		138,369		140,637		615,351		446,796		378,364
Other income (expense)
Interest expense																	(43,049)		(50,992)		(39,875)
Debt retirement costs																	(7,082)		0		0
Gain from sales of equity securities																	16,429		0		0
Other income, net																	3,520		5,628		4,471
Income before income taxes																	585,169		401,432		342,960
Provision for income taxes																	199,614		142,466		121,567
Net income	$ 95,277		$ 86,964		$ 115,501		$ 87,813		$ 26,443		$ 67,930		$ 81,049		$ 83,544		$ 385,555		$ 258,966		$ 221,393
Earnings per common share:
Basic	$ 1.43	[2]	$ 1.30	[2]	$ 1.73	[2]	$ 1.32	[2]	$ 0.40	[2]	$ 1.02	[2]	$ 1.22	[2]	$ 1.26	[2]	$ 5.78		$ 3.89		$ 3.35
Diluted	$ 1.42	[2]	$ 1.30	[2]	$ 1.72	[2]	$ 1.31	[2]	$ 0.40	[2]	$ 1.01	[2]	$ 1.21	[2]	$ 1.25	[2]	$ 5.75		$ 3.87		$ 3.34
Weighted average shares outstanding:
Basic																	66,289,429		65,927,421		65,472,875
Diluted																	66,641,495		66,300,158		65,676,664
Dividends per common share	$ 0.1875																$ 4.2725		$ 0.2746		$ 0.2420

[1] Revenues are attributed to countries based on location of customer.

[2] Basic and diluted earnings per common share ("EPS") for each quarter is computed using the weighted average shares outstanding during that quarter, while EPS for the year is computed using the weighted average shares outstanding for the year. As a result, the sum of the EPS for each of the four quarters may not equal the EPS for the year.