Schedule of Intangible Assets (Tables)

9 Months Ended

Sep. 30, 2017

Intangible Assets, Net (Excluding Goodwill) [Abstract]

Schedule of Intangible Assets by Major Class [Table Text Block]

The gross carrying amount and accumulated amortization of our intangible assets, other than goodwill, were as follows:

	September 30, 2017							December 31, 2016
	Gross Assets		Accumulated Amortization			Net		Gross Assets		Accumulated Amortization			Net
	(in thousands)
Core-developed technology	$	425,198	$	(393,831	)	$	31,367	$	372,568	$	(354,878	)	$	17,690
Customer contracts and relationships	256,840		(193,317		)	63,523		224,467		(170,056		)	54,411
Trademarks and trade names	69,706		(65,537		)	4,169		61,785		(61,766		)	19
Other	11,582		(11,062		)	520		11,076		(11,045		)	31
Total intangible assets subject to amortization	$	763,326	$	(663,747	)	$	99,579	$	669,896	$	(597,745	)	$	72,151
In-process research and development	710		—			710		—		—			—
Total intangible assets	$	764,036	$	(663,747	)	$	100,289	$	669,896	$	(597,745	)	$	72,151

Summary of Intangible Asset Account Activity [Table Text Block]

A summary of intangible asset activity is as follows:

	Nine Months Ended September 30,
	2017		2016
	(in thousands)
Beginning balance, intangible assets, gross	$	669,896	$	702,507
Intangible assets acquired	36,500		—
Effect of change in exchange rates	57,640		2,309
Ending balance, intangible assets, gross	$	764,036	$	704,816

Schedule of Intangible Assets, Future Amortization Expense [Table Text Block]

Estimated future annual amortization expense is as follows:

Year Ending December 31,	Estimated Annual Amortization
	(in thousands)
2017 (amount remaining at September 30, 2017)	$	5,605
2018	19,065
2019	16,302
2020	14,003
2021	11,995
Beyond 2021	32,609
Total intangible assets subject to amortization	$	99,579