CONDENSED CONSOLIDATED STATEMENTS OF EARNINGS (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Net sales
Product sales	$ 423,229	$ 402,918
Service sales	100,362	100,589
Total net sales	523,591	503,507
Cost of sales
Cost of product sales	286,492	264,735
Cost of service sales	66,324	66,869
Total cost of sales	352,816	331,604
Gross profit	170,775	171,903
Research and development expenses	15,298	15,160
Selling expenses	28,953	29,626
General and administrative expenses	75,297	69,854
Operating income	51,227	57,263
Interest expense	(10,377)	(9,933)
Other income, net	312	234
Earnings before income taxes	41,162	47,564
Provision for income taxes	(8,615)	(14,745)
Net earnings	$ 32,547	$ 32,819
Earnings Per Share, Basic [Abstract]
Basic earnings per share (usd per share)	$ 0.74	$ 0.74
Earnings Per Share, Diluted [Abstract]
Diluted earnings per share (usd per share)	0.73	0.73
Dividends per share	$ 0.13	$ 0.13
Weighted average shares outstanding:
Basic (shares)	44,246	44,578
Diluted (shares)	44,860	45,240