Accounting Policies - Reclassifications Out of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Cost of sales	$ 658,290	$ 486,212	$ 1,304,617	$ 1,003,063
Income from Operations	96,729	127,086	196,194	264,550
Income tax expense	(24,569)	(36,601)	(52,030)	(79,902)
Interest expense, net	(15,420)	(4,969)	(33,132)	(9,840)
Net income attributable to Wabtec shareholders	72,025	90,485	145,914	184,648
Reclassification out of Accumulated Other Comprehensive Income | Pension and post retirement benefit plans
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Income from Operations	818	549	1,636	1,284
Income tax expense	(226)	(157)	(452)	(388)
Net income attributable to Wabtec shareholders	592	392	1,184	896
Reclassification out of Accumulated Other Comprehensive Income | Amortization of initial net obligation and prior service cost
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Cost of sales	(422)	(422)	(844)	(807)
Reclassification out of Accumulated Other Comprehensive Income | Amortization of net loss
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Cost of sales	1,240	971	2,480	2,091
Reclassification out of Accumulated Other Comprehensive Income | Derivative contracts
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Income tax expense	(149)	(130)	(312)	(280)
Interest expense, net	566	453	1,155	927
Net income attributable to Wabtec shareholders	$ 417	$ 323	$ 843	$ 647