Intangible Assets (Tables)

3 Months Ended

Mar. 31, 2017

Intangible Assets [Abstract]

Intangible Assets Other Than Goodwill

	2017						2016
(in thousands)	Gross		Accumulated Amortization		Net		Gross		Accumulated Amortization		Net		Useful Life (in years)	Weighted Average Useful Life Remaining (in years)
Intangible assets with finite lives:
Patent costs	$	16,969	$	(6,337)	$	10,632	$	16,263	$	(5,873)	$	10,390	1-20	9
Acquired technology		54,192		(31,125)		23,067		52,881		(27,543)		25,338	1-16	4
Acquired patents		16,982		(11,093)		5,889		17,047		(9,454)		7,593	1-6	4
Customer relationships		103,106		(49,576)		53,530		99,067		(46,252)		52,815	1-14	6
Trade secrets		19,254		(9,926)		9,328		19,530		(7,919)		11,611	7	4
Trade names		32,926		(16,936)		15,990		28,110		(16,015)		12,095	1-8	5
Other		23,971		(19,813)		4,158		22,953		(21,294)		1,659	2-4	2
Total intangible assets	$	267,400	$	(144,806)	$	122,594	$	255,851	$	(134,350)	$	121,501	1-20	4