Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 76,025	$ 27,289
OTHER COMPREHENSIVE INCOME:
Foreign currency translation adjustment	(617)	36,253
Net unrealized gain/(loss) on qualifying cash flow hedges, net of tax (provision)/benefit	6,901	506
Changes in pension and other postretirement benefits, net of tax (provision)/benefit	43	(893)
Other comprehensive income/(loss)	6,327	35,866
COMPREHENSIVE INCOME	82,352	63,155
Less: Comprehensive income attributable to noncontrolling interest	(3,091)	13,086
COMPREHENSIVE INCOME ATTRIBUTABLE TO G&W	$ 85,443	$ 50,069