CONSOLIDATED STATEMENTS OF COMPREHENSIVE EARNINGS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net earnings	$ 570,267	$ 811,665	$ 508,892
Foreign currency translation adjustments [Abstract]
Foreign currency translation gains (losses)	(59,970)	143,064	(106,526)
Reclassification of foreign currency translation losses (gains) to earnings	0	3,992	823
Total foreign currency translation adjustments	(59,970)	147,056	(105,703)
Pension and other postretirement benefit plans [Abstract]
Actuarial gains (losses)	(13,107)	12,439	(7,928)
Prior service credit (cost)	(14,661)	3,136	(776)
Amortization of actuarial losses including in net periodic pension cost	3,829	5,267	5,683
Amortization of prior service costs included in net periodic pension cost	2,875	3,007	4,397
Settlement and curtailment	9,926	(2,462)	0
Total pension and other postretirement benefit plans	(11,138)	21,387	1,376
Changes in fair value of cash flow hedges [Abstract]
Unrealized net (losses) gains	1,158	(1,801)	144
Net (gains) losses reclassified into earnings	1,541	(590)	415
Total cash flow hedges	2,699	(2,391)	559
Other	0	(1,485)	(985)
Other comprehensive earnings (loss), net of tax	(68,409)	164,567	(104,753)
Comprehensive earnings	$ 501,858	$ 976,232	$ 404,139