CONDENSED CONSOLIDATED STATEMENTS OF INCOME - UNAUDITED - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Revenue	$ 245,617	$ 244,793
Cost of revenue (exclusive of depreciation, shown separately below)	131,206	128,963
Other operating expenses:
Research and development	30,337	32,591
Selling, general and administrative	44,384	45,918
Depreciation	5,565	5,113
Restructuring and reorganization charges	966	115
Total operating expenses	212,458	212,700
Operating income	33,159	32,093
Other income (expense):
Interest expense	(4,213)	(4,560)
Amortization of original issue discount	(730)	(690)
Interest and investment income, net	529	519
Other, net	(69)	(1,511)
Total other	(4,483)	(6,242)
Income before income taxes	28,676	25,851
Income tax provision	(7,162)	(6,600)
Net income	$ 21,514	$ 19,251
Weighted-average shares outstanding:
Basic	31,994	32,128
Diluted	32,358	32,438
Earnings per common share:
Basic	$ 0.67	$ 0.60
Diluted	$ 0.66	$ 0.59