CONSOLIDATED STATEMENTS OF EARNINGS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue, Net [Abstract]
Product sales	$ 1,854,216	$ 1,714,358	$ 1,796,802
Service sales	416,810	394,573	408,881
Net sales	2,271,026	2,108,931	2,205,683
Cost of Revenue [Abstract]
Cost of product sales	1,184,358	1,100,287	1,156,596
Cost of service sales	268,073	258,161	265,832
Total cost of sales	1,452,431	1,358,448	1,422,428
Gross profit	818,595	750,483	783,255
Research and development expenses	(60,308)	(58,592)	(60,837)
Selling expenses	(120,002)	(111,228)	(121,482)
General and administrative expenses	(298,542)	(272,565)	(290,319)
Operating income	339,743	308,098	310,617
Interest expense	(41,471)	(41,248)	(36,038)
Other income, net	1,347	1,111	615
Earnings before income taxes	299,619	267,961	275,194
Provision for income taxes	(84,728)	(78,579)	(82,946)
Earnings from continuing operations	214,891	189,382	192,248
Discontinued operations, net of taxes
Loss from discontinued operations, net of taxes	0	2,053	46,787
Net earnings	$ 214,891	$ 187,329	$ 145,461
Basic earnings per share
Earnings from continuing operations	$ 4.86	$ 4.27	$ 4.12
Earnings from discontinued operations	0.00	(0.05)	(1.00)
Total	4.86	4.22	3.12
Diluted earnings per share
Earnings from continuing operations	4.80	4.20	4.04
Earnings from discontinued operations	0.00	(0.05)	(0.99)
Total	4.80	4.15	3.05
Dividends per share	$ 0.56	$ 0.52	$ 0.52
Weighted average shares outstanding:
Basic	44,182	44,389	46,624
Diluted	44,761	45,045	47,616