CONSOLIDATED STATEMENTS OF COMPREHENSIVE EARNINGS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net earnings	$ 811,665	$ 508,892	$ 869,829
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Tax	(7,397)	(4,560)	(11,791)
Foreign currency translation adjustments [Abstract]
Foreign currency translation gains (losses)	143,064	(106,526)	(117,302)
Reclassification of foreign currency translation losses (gains) to earnings	3,992	823	(3,092)
Total foreign currency translation adjustments	147,056	(105,703)	(120,394)
Pension and other postretirement benefit plans [Abstract]
Actuarial gains (losses)	12,439	(7,928)	4,492
Prior service credit (cost)	3,136	(776)	4,171
Amortization of actuarial losses including in net periodic pension cost	5,267	5,683	10,280
Amortization of prior service costs included in net periodic pension cost	3,007	4,397	4,993
Settlement and curtailment	(2,462)	0	0
Total pension and other postretirement benefit plans	21,387	1,376	23,936
Changes in fair value of cash flow hedges [Abstract]
Unrealized net (losses) gains	(1,801)	144	(328)
Net (gains) losses reclassified into earnings	(590)	415	(108)
Total cash flow hedges	(2,391)	559	(436)
Other	(1,485)	(985)	1,252
Other comprehensive earnings (loss), net of tax	164,567	(104,753)	(95,642)
Comprehensive earnings	$ 976,232	$ 404,139	$ 774,187