Schedule of Intangible Assets (Tables)

6 Months Ended

Jun. 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:

	June 30, 2017							December 31, 2016
	Gross Assets		Accumulated Amortization			Net		Gross Assets		Accumulated Amortization			Net
	(in thousands)
Core-developed technology	$	415,616	$	(382,015	)	$	33,601	$	372,568	$	(354,878	)	$	17,690
Customer contracts and relationships	250,683		(185,659		)	65,024		224,467		(170,056		)	54,411
Trademarks and trade names	68,626		(64,340		)	4,286		61,785		(61,766		)	19
Other	11,579		(11,056		)	523		11,076		(11,045		)	31
Total intangible assets subject to amortization	$	746,504	$	(643,070	)	$	103,434	$	669,896	$	(597,745	)	$	72,151
In-process research and development	710		—			710		—		—			—
Total intangible assets	$	747,214	$	(643,070	)	$	104,144	$	669,896	$	(597,745	)	$	72,151

Summary of Intangible Asset Account Activity [Table Text Block]

A summary of intangible asset activity is as follows:

	Six Months Ended June 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	40,818		(2,512		)
Ending balance, intangible assets, gross	$	747,214	$	699,995

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 June 30, 2017)	$	11,103
2018	18,761
2019	16,050
2020	13,698
2021	11,799
Beyond 2021	32,023
Total intangible assets subject to amortization	$	103,434