CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 28, 2018	Sep. 29, 2017
Statement of Cash Flows [Abstract]
Net income	$ 106,023	$ 151,667
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and impairment charges	110,597	101,843
Stock-based compensation expense	18,867	15,633
Non-cash interest expense	3,332	3,340
Loss on short term investments	10,128	0
Deferred income tax benefit	(21,730)	(6,046)
Gain on sale of property, plant and equipment	(8,211)	(10,557)
Loss on sale of business	4,337	0
Changes in operating assets and liabilities:
Trade receivables, net	(51,722)	(96,472)
Inventories, net	(56,951)	(38,493)
Accounts payable	6,486	(3,308)
Customer advances and billings in excess of costs incurred	18,970	(18,405)
Changes in other operating assets and liabilities	(39,318)	15,489
Net cash provided by operating activities	100,808	114,691
Cash flows from investing activities:
Purchases of property, plant and equipment	(40,247)	(36,756)
Proceeds from sale of property, plant and equipment	17,758	16,106
Acquisitions, net of cash received	(83,846)	(56,931)
Sale of business, net	18,626	0
Sale of short term investments, net	139,480	0
Net cash provided by (used in) investing activities	51,771	(77,581)
Cash flows from financing activities:
Payments under term credit facility	(93,750)	(46,878)
Proceeds from borrowings on revolving credit facilities and other	911,772	594,159
Repayments of borrowings on revolving credit facilities and other	(722,573)	(911,462)
Proceeds from borrowings on senior unsecured notes	0	374,450
Proceeds from issuance of common stock, net	4,648	4,758
Common stock repurchases	(200,000)	0
Other	(1,038)	(8,851)
Net cash (used in) provided by financing activities	(100,941)	6,176
Effect of foreign exchange rates on Cash and cash equivalents	(27,757)	7,434
Increase in Cash and cash equivalents	23,881	50,720
Cash and Cash Equivalents- beginning of period	262,019	221,730
Cash and Cash Equivalents- end of period	$ 285,900	$ 272,450