Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Numerator
Net income attributable to Wabtec shareholders	$ 88,366	$ 73,889
Less: dividends declared - common shares and non-vested restricted stock	(11,531)	(9,572)
Undistributed earnings	$ 76,835	$ 64,317
Percentage allocated to common shareholders (as a percent)	99.70%	99.70%
Undistributed earnings allocated to common shareholders	$ 76,604	$ 64,124
Add: dividends declared - common shares	11,497	9,542
Numerator for basic and diluted earnings per common share	$ 88,101	$ 73,666
Denominator
Basic weighted average common shares outstanding (in shares)	95,810	95,243
Assumed conversion of dilutive stock-based compensation plans (in shares)	561	748
Denominator for diluted earnings per common share - adjusted weighted average shares and assumed conversion (in shares)	96,371	95,991
Net income attributable to Wabtec shareholders per common share
Basic (in dollars per share)	$ 0.92	$ 0.77
Diluted (in dollars per share)	$ 0.92	$ 0.77
Basic weighted-average common shares outstanding and non-vested restricted stock expected to vest (in shares)	96,091	95,544