CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands		3 Months Ended							6 Months Ended				12 Months Ended
		Jun. 30, 2018		Dec. 31, 2017	Sep. 30, 2017	Jul. 01, 2017		Apr. 01, 2017	Jun. 30, 2018		Jul. 01, 2017		Dec. 31, 2017
Income Statement [Abstract]
Sales		$ 7,392,528	[1]	$ 7,539,449	$ 6,856,108	$ 6,422,226	[1]	$ 5,736,780	$ 14,268,141	[1]	$ 12,159,006	[1]	$ 26,554,563
Cost of sales		6,459,708		6,610,269	6,013,541	5,598,202		4,975,583	12,466,377		10,573,785		23,197,595
Gross Profit		932,820				824,024			1,801,764		1,585,221
Operating expenses:
Selling, general, and administrative expenses		580,388				531,781			1,143,357		1,047,307
Depreciation and amortization		46,422				37,381			93,669		74,522
Loss on disposition of businesses, net		0				0			1,562		0
Restructuring, integration, and other charges		19,183				24,416			40,354		39,921
Total operating expenses		645,993				593,578			1,278,942		1,161,750
Operating income		286,827		286,824	235,441	230,446		193,025	522,822		423,471		945,736
Equity in earnings (losses) of affiliated companies		517				724			(156)		1,649
Gain (loss) on investments, net		(2,563)				2,263			(5,015)		4,245
Loss on extinguishment of debt		0				58,759			0		58,759		58,759
Post-retirement expense		1,257				1,897			2,488		3,697
Interest and other financing expense, net		60,803				42,538			105,982		80,787
Income before income taxes		222,721				130,239			409,181		286,122
Provision for income taxes		51,681				29,592			98,271		69,156
Consolidated net income		171,040				100,647			310,910		216,966
Noncontrolling interests		1,125				925			1,901		2,507
Net income attributable to shareholders		$ 169,915		$ 53,653	$ 134,064	$ 99,722		$ 114,737	$ 309,009		$ 214,459		$ 402,176
Net income per share:
Basic		$ 1.94				$ 1.12			$ 3.52		$ 2.41
Diluted	[2]	$ 1.92				$ 1.11			$ 3.48		$ 2.38
Weighted-average shares outstanding:
Basic		87,802				88,876			87,878		89,079
Diluted		88,652				89,837			88,841		90,146

[1] Includes sales related to the United States of $2,968,469 and $5,618,137 for the second quarter and first six months of 2018 and $2,667,958 and $5,010,086 for the second quarter and first six months of 2017, respectively.

[2] Stock-based compensation awards for the issuance of 915 and 515 shares for the second quarter and first six months of 2018 and 432 and 328 shares for the second quarter and first six months of 2017, respectively, were excluded from the computation of net income per share on a diluted basis as their effect was anti-dilutive.