CONDENSED CONSOLIDATED STATEMENTS OF EARNINGS (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net sales
Product sales	$ 444,687	$ 423,229
Service sales	102,835	100,362
Total net sales	547,522	523,591
Cost of sales
Cost of product sales	299,311	289,610
Cost of service sales	67,020	67,046
Total cost of sales	366,331	356,656
Gross profit	181,191	166,935
Research and development expenses	15,941	15,591
Selling expenses	31,520	29,458
General and administrative expenses	69,232	74,194
Operating income	64,498	47,692
Interest expense	(8,204)	(10,377)
Other income, net	4,683	3,847
Earnings before income taxes	60,977	41,162
Provision for income taxes	(17,334)	(8,615)
Net earnings	$ 43,643	$ 32,547
Earnings Per Share, Basic [Abstract]
Basic earnings per share (usd per share)	$ 0.99	$ 0.74
Earnings Per Share, Diluted [Abstract]
Diluted earnings per share (usd per share)	0.98	0.73
Dividends per share	$ 0.15	$ 0.13
Weighted average shares outstanding:
Basic (shares)	44,188	44,246
Diluted (shares)	44,678	44,860