Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net income	$ 57,217	$ 57,303	$ 25,915
Adjustments to reconcile net income to cash flows:
Depreciation and amortization	22,061	23,826	22,473
Non-cash deferred revenue	(12,372)	$ (17,873)	$ (10,093)
Restructuring expenses	$ 15,573
Loss on voluntary pension settlement		$ 7,170
Increase in inventory reserve	$ 3,119	5,343	$ 2,329
Gain on sale of assets		(1,099)	(4,281)
Allowance for doubtful accounts	$ (11)	61	433
Stock based compensation	5,599	5,002	2,825
Deferred income tax provision	$ 19,736	(16,025)	5,902
Equity in losses of partially-owned affiliates		4,623	2,262
Other	$ (130)	523	348
Changes in assets and liabilities:
Trade receivables	(14,378)	(8,955)	(27,707)
Inventories	(32,721)	(9,062)	(19,328)
Prepaid expenses and other current assets	4,268	(5,766)	(2,651)
Accounts payable and other current liabilities	10,334	12,369	10,107
Deferred revenue and advance payments	12,178	11,773	18,644
Other non-current assets and liabilities	(5,331)	(2,387)	11,229
Discontinued operations:
Net cash used in discontinued operations	(1,536)	(1,858)	(1,533)
Net cash provided by operating activities	83,606	64,968	36,874
Cash flows from investing activities:
Capital expenditures	(62,491)	(23,323)	(57,320)
Proceeds from sale of assets	$ 2,308	2,355	2,378
Advances to partially-owned affiliates		(1,404)	$ (1,655)
Acquisition of business and equity investment, net of cash acquired		$ (2,426)
Other	$ (56)
Net cash used in investing activities	$ (60,239)	$ (24,798)	$ (56,597)
Cash flows from financing activities:
Borrowings		25,750	70,950
Repayments	$ (30,000)	(45,000)	(55,700)
Proceeds from stock options exercised	5,816	4,203	3,224
Other	1,445	522	(301)
Net cash (used in)/provided by financing activities	(22,739)	(14,525)	18,173
Effect of exchange rate changes on cash and cash equivalents	(2,172)	(2,872)	744
Net (decrease)/increase in cash and cash equivalents	(1,544)	22,773	(806)
Cash and cash equivalents at beginning of year	45,518	22,745	23,551
Cash and cash equivalents at end of year	43,974	45,518	22,745
Supplemental disclosure:
Interest paid, net of capitalized interest	1,340	2,068	2,325
Income taxes paid, net of refunds received	$ 5,731	$ 6,725	$ 7,211