Accounting Policies - Reclassifications Out of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Cost of sales	$ 704,728	$ 463,093	$ 2,009,345	$ 1,466,156
Income from Operations	81,185	115,227	277,379	379,777
Income tax expense	(12,746)	(32,799)	(64,776)	(112,701)
Interest expense, net	(17,893)	(6,057)	(51,025)	(15,897)
Net income attributable to Wabtec shareholders	67,399	82,428	213,313	267,076
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	617	2,454	1,901
Income tax expense	(226)	(175)	(678)	(574)
Net income attributable to Wabtec shareholders	592	442	1,776	1,327
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)	6	(1,266)	(801)
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	611	3,720	2,702
Reclassification out of Accumulated Other Comprehensive Income | Derivative contracts
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Income tax expense	(131)	(96)	(447)	(382)
Interest expense, net	497	338	1,653	1,265
Net income attributable to Wabtec shareholders	$ 366	$ 242	$ 1,206	$ 883