CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating Activities
Net income	$ 87,457	$ 72,004
Adjustments to reconcile net income to cash provided by operations:
Depreciation and amortization	27,854	25,229
Stock-based compensation expense	5,696	5,692
(Gain) loss on disposal of property, plant and equipment	(24)	153
Changes in operating assets and liabilities, net of acquisitions
Accounts receivable and unbilled accounts receivable	(66,347)	(96,481)
Inventories	(50,755)	(32,145)
Accounts payable	32,096	(24,690)
Accrued income taxes	14,004	2,188
Accrued liabilities and customer deposits	(1,529)	85,303
Other assets and liabilities	(24,252)	(63,349)
Net cash provided by (used for) operating activities	24,200	(26,096)
Investing Activities
Purchase of property, plant and equipment	(17,466)	(19,327)
Proceeds from disposal of property, plant and equipment	7,898	284
Acquisitions of businesses, net of cash acquired	(34,297)	(800,081)
Net cash used for investing activities	(43,865)	(819,124)
Financing Activities
Proceeds from debt	306,610	458,273
Payments of debt	(266,347)	(482,591)
Proceeds from exercise of stock options and other benefit plans	2,873	1,259
Payment of income tax withholding on share-based compensation	(2,937)	(6,842)
Cash dividends ($0.12 and $0.10 per share for the three months ended March 31, 2018 and 2017, respectively)	(11,531)	(9,572)
Net cash provided by (used for) financing activities	28,668	(39,473)
Effect of changes in currency exchange rates	7,482	21,640
Increase (Decrease) in cash	16,485	(863,053)
Cash, cash equivalents and restricted cash, beginning of period	233,401	1,143,232
Cash and cash equivalents, end of period	$ 249,886	$ 280,179