Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating activities
Net income	$ 60,249	$ 35,053	$ 15,003
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	63,215	68,318	75,993
Stock-based compensation	21,407	18,035	14,089
Amortization of prepaid debt fees	1,067	1,076	2,128
Deferred taxes, net	50,667	13,790	1,488
Restructuring, non-cash	(2,297)	7,188	976
Other adjustments, net	3,673	4,309	2,003
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	(17,573)	(27,162)	(9,009)
Inventories	(16,242)	22,343	(52,737)
Other current assets	8,112	20,705	12,512
Other long-term assets	11,230	(339)	(3,721)
Accounts payables, other current liabilities, and taxes payable	78,463	(37,312)	(7,060)
Wages and benefits payable	1,926	7,808	(10,866)
Unearned revenue	(41,309)	(25,810)	11,943
Warranty	(10,554)	(10,246)	20,161
Other operating, net	(20,680)	18,086	447
Net Cash Provided by (Used in) Operating Activities, Continuing Operations	191,354	115,842	73,350
Investing activities
Acquisitions of property, plant, and equipment	(49,495)	(43,543)	(43,918)
Payments to Acquire Businesses, Net of Cash Acquired	(99,386)	(951)	(5,754)
Other investing, net	702	(3,034)	721
Net cash used in investing activities	(148,179)	(47,528)	(48,951)
Financing activities
Proceeds from borrowings	335,000	15,877	113,467
Payments on debt	(29,063)	(79,119)	(62,998)
Issuance of common stock	3,609	2,891	2,663
Repurchase of common stock	0	0	(38,283)
Other financing, net	(7,587)	(2,672)	(7,109)
Net cash provided by (used in) financing activities	301,959	(63,023)	7,740
Effect of foreign exchange rate changes on cash, cash equivalents, and restricted cash	8,636	(2,744)	(13,492)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect	353,770	2,547	18,647
Cash, cash equivalents, and restricted cash at beginning of period	133,565	131,018
Cash, cash equivalents, and restricted cash at end of period	176,274	133,565	131,018
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	487,335	133,565	131,018
Supplemental disclosure of cash flow information:
Income taxes, net	28,969	24,287	29,189
Interest	$ 10,106	$ 9,921	$ 10,198