Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 53,385	$ 56,785	$ 128,802	$ 132,203
OTHER COMPREHENSIVE INCOME:
Foreign currency translation adjustment	32,902	5,108	100,054	3,618
Net unrealized gain/(loss) on qualifying cash flow hedges, net of tax (provision)/benefit	736	(2,127)	638	(18,364)
Changes in pension and other postretirement benefits, net of tax (provision)/benefit	38	1,449	(2,149)	4,372
Other comprehensive income/(loss)	33,676	4,430	98,543	(10,374)
COMPREHENSIVE INCOME	87,061	61,215	227,345	121,829
Less: Comprehensive income attributable to noncontrolling interest	8,500	0	24,663	0
COMPREHENSIVE INCOME ATTRIBUTABLE TO G&W	$ 78,561	$ 61,215	$ 202,682	$ 121,829