Accumulated Other Comprehensive Income/(Loss) AOCI Attributbale to G&W (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accumulated other comprehensive loss, beginning balance	$ (211,336)	$ (153,457)
Other comprehensive loss before reclassifications	23,984	21,860
Amounts reclassified from accumulated other comprehensive loss, net of tax(provision)/benefit	(153)	1,753
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	23,831	23,613
Accumulated other comprehensive income loss, ending balance	(187,505)	(129,844)
Foreign Currency Translation Adjustment [Member]
Accumulated other comprehensive loss, beginning balance	(177,662)	(156,146)
Other comprehensive loss before reclassifications	23,630	31,121
Amounts reclassified from accumulated other comprehensive loss, net of tax(provision)/benefit	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	23,630	31,121
Accumulated other comprehensive income loss, ending balance	(154,032)	(125,025)
Defined Benefit Plans [Member]
Accumulated other comprehensive loss, beginning balance	(19,948)	11,005
Other comprehensive loss before reclassifications	(931)	0
Amounts reclassified from accumulated other comprehensive loss, net of tax(provision)/benefit	38	1,923
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(893)	1,923
Accumulated other comprehensive income loss, ending balance	(20,841)	12,928
Tax (provision)/benefit on amounts reclassified from AOCI for defined benefit plans	(20)	120
Net Unrealized Gain/(Loss) on Cash Flow Hedges [Member]
Accumulated other comprehensive loss, beginning balance	(13,726)	(8,316)
Other comprehensive loss before reclassifications	1,285	(9,261)
Amounts reclassified from accumulated other comprehensive loss, net of tax(provision)/benefit	(191)	(170)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	1,094	(9,431)
Accumulated other comprehensive income loss, ending balance	(12,632)	(17,747)
Tax (provision)/benefit on amounts reclassified from AOCI for cash flow hedges	$ (520)	$ 113