CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Revenue	$ 434,898	$ 464,712	$ 1,327,223	$ 1,305,650
Cost of goods sold	212,824	241,821	654,684	684,706
Gross profit	222,074	222,891	672,539	620,944
Operating expenses:
Research and development	41,997	42,873	132,987	127,902
Selling, general and administrative	91,525	92,932	296,664	280,240
Loss on sale of business	0	0	10,178	0
Total operating expenses	133,522	135,805	439,829	408,142
Earnings from operations	88,552	87,086	232,710	212,802
Interest expense	4,042	3,819	12,086	12,744
Interest income	(979)	(488)	(2,591)	(1,114)
Other income, net	71	(778)	229	(2,465)
Earnings before income taxes	85,418	84,533	222,986	203,637
Income tax provision	12,267	21,004	39,077	46,124
Net earnings	$ 73,151	$ 63,529	$ 183,909	$ 157,513
Net earnings per share:
Basic earnings per share (in dollars per share)	$ 0.53	$ 0.46	$ 1.33	$ 1.15
Diluted earnings per share (in dollars per share)	$ 0.52	$ 0.46	$ 1.31	$ 1.13
Weighted Average Number of Shares Outstanding, Basic	138,190	137,849	138,146	137,030
Weighted Average Number of Shares Outstanding, Diluted	140,327	139,419	140,613	138,853