Accounting Policies - Reclassifications Out of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Other income (expense), net	$ 2,171	$ 936	$ 4,757	$ 5,747
Income tax expense	(10,503)	(24,569)	(36,627)	(52,030)
Interest expense, net	(31,920)	(17,564)	(52,204)	(37,422)
Net income attributable to Wabtec shareholders	84,416	72,025	172,782	145,914
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]
Other income (expense), net	718	818	1,435	1,636
Income tax expense	(198)	(226)	(396)	(452)
Net income attributable to Wabtec shareholders	520	592	1,039	1,184
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]
Other income (expense), net	(375)	(422)	(751)	(844)
Reclassification out of Accumulated Other Comprehensive Income | Amortization of net loss
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Other income (expense), net	1,093	1,240	2,186	2,480
Reclassification out of Accumulated Other Comprehensive Income | Derivative contracts
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Income tax expense	(42)	(149)	(276)	(312)
Interest expense, net	176	566	855	1,155
Net income attributable to Wabtec shareholders	$ 134	$ 417	$ 579	$ 843