Certain Balance Sheet Components (Tables)

9 Months Ended

Sep. 30, 2016

Balance Sheet Related Disclosures [Abstract]

Accounts Receivable, Net [Table Text Block]

Accounts receivable, net	September 30, 2016		December 31, 2015
	(in thousands)
Trade receivables (net of allowance of $4,254 and $5,949)	$	319,929	$	298,550
Unbilled receivables	48,781		32,345
Total accounts receivable, net	$	368,710	$	330,895

Allowance for Credit Losses on Financing Receivables [Table Text Block]

Allowance for doubtful accounts activity	Three Months Ended September 30,						Nine Months Ended September 30,
	2016			2015			2016			2015
	(in thousands)
Beginning balance	$	3,939		$	5,422		$	5,949		$	6,195
Provision (release) for doubtful accounts, net	353			(141		)	265			(111		)
Accounts written-off	(77		)	(162		)	(1,919		)	(503		)
Effect of change in exchange rates	39			(160		)	(41		)	(622		)
Ending balance	$	4,254		$	4,959		$	4,254		$	4,959

Inventories [Table Text Block]

Inventories	September 30, 2016		December 31, 2015
	(in thousands)
Materials	$	112,507	$	111,191
Work in process	9,919		9,400
Finished goods	67,127		69,874
Total inventories	$	189,553	$	190,465

Property, Plant, and Equipment, Net [Table Text Block]

Property, plant, and equipment, net	September 30, 2016			December 31, 2015
	(in thousands)
Machinery and equipment	$	290,395		$	289,015
Computers and software	105,791			104,310
Buildings, furniture, and improvements	127,297			127,531
Land	18,069			19,882
Construction in progress, including purchased equipment	26,956			32,639
Total cost	568,508			573,377
Accumulated depreciation	(387,641		)	(383,121		)
Property, plant, and equipment, net	$	180,867		$	190,256

Depreciation Expense [Table Text Block]

Depreciation expense	Three Months Ended September 30,				Nine Months Ended September 30,
	2016		2015		2016		2015
	(in thousands)
Depreciation expense	$	11,086	$	11,129	$	32,561	$	34,060