Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Numerator
Net income attributable to Wabtec shareholders	$ 84,416	$ 72,025	$ 172,782	$ 145,914
Less: dividends declared - common shares and non-vested restricted stock	(11,565)	(9,605)	(23,096)	(19,177)
Undistributed earnings	$ 72,851	$ 62,420	$ 149,686	$ 126,737
Percentage allocated to common shareholders (as a percent)	99.70%	99.70%	99.70%	99.70%
Undistributed earnings allocated to common shareholders	$ 72,632	$ 62,233	$ 149,237	$ 126,357
Add: dividends declared - common shares	11,531	9,576	23,027	19,120
Numerator for basic and diluted earnings per common share	$ 84,163	$ 71,809	$ 172,264	$ 145,477
Denominator
Basic weighted average common shares outstanding (in shares)	95,992	95,641	95,867	95,370
Assumed conversion of dilutive stock-based compensation plans (in shares)	583	643	604	701
Denominator for diluted earnings per common share - adjusted weighted average shares and assumed conversion (in shares)	96,575	96,284	96,471	96,071
Net income attributable to Wabtec shareholders per common share
Basic (in dollars per share)	$ 0.88	$ 0.75	$ 1.80	$ 1.52
Diluted (in dollars per share)	$ 0.87	$ 0.75	$ 1.79	$ 1.52
Basic weighted-average common shares outstanding and non-vested restricted stock expected to vest (in shares)	96,276	95,917	96,153	95,666