Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net income	$ 81,678	$ 57,217	$ 57,303
Adjustments to reconcile net income to cash flows:
Depreciation and amortization	24,665	22,061	23,826
Non-cash deferred revenue	(25,822)	(12,372)	(17,873)
Restructuring expenses	1,138	15,573
Loss on voluntary pension settlement			7,170
Increase in inventory reserve	7,885	3,119	5,343
(Gain)/loss on sale of assets	(33)	120	(1,099)
Stock based compensation	7,766	5,599	5,002
Deferred income tax provision	8,556	19,736	(16,025)
Equity in losses of partially-owned affiliates			4,623
Other	193	(261)	584
Changes in assets and liabilities:
Trade receivables	(5,120)	(14,378)	(8,955)
Inventories	(23,679)	(32,721)	(9,062)
Prepaid expenses and other current assets	(729)	4,268	(5,766)
Accounts payable and other current liabilities	1,778	10,334	12,369
Deferred revenue and advance payments	41,962	12,178	11,773
Other non-current assets and liabilities	(3,961)	(5,331)	(2,387)
Discontinued operations:
Non-current liabilities	7,517
Net cash used in discontinued operations	(516)	(1,536)	(1,858)
Net cash provided by operating activities	123,278	83,606	64,968
Cash flows from investing activities:
Capital expenditures	(49,714)	(62,491)	(23,323)
Proceeds from sale of assets	13	2,308	2,355
Advances to partially-owned affiliates			(1,404)
Acquisition of business and equity investment, net of cash acquired	(24,275)		(2,426)
Other		(56)
Net cash used in investing activities	(73,976)	(60,239)	(24,798)
Cash flows from financing activities:
Borrowings			25,750
Repayments	(30,000)	(30,000)	(45,000)
Proceeds from stock options exercised	4,941	5,816	4,203
Debt issuance costs	(2,515)
Excess tax benefits	10,278	1,445	522
Net cash used in financing activities	(17,296)	(22,739)	(14,525)
Effect of exchange rate changes on cash and cash equivalents	(1,839)	(2,172)	(2,872)
Net increase/(decrease) in cash and cash equivalents	30,167	(1,544)	22,773
Cash and cash equivalents at beginning of year	43,974	45,518	22,745
Cash and cash equivalents at end of year	74,141	43,974	45,518
Supplemental disclosure:
Interest paid, net of capitalized interest	425	1,340	2,068
Income taxes paid, net of refunds received	$ 18,210	$ 5,731	$ 6,725