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, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Numerator
Net income attributable to Wabtec shareholders	$ 72,025	$ 90,485	$ 145,914	$ 184,648
Less: dividends declared - common shares and non-vested restricted stock	(9,605)	(7,209)	(19,177)	(14,565)
Undistributed earnings	$ 62,420	$ 83,276	$ 126,737	$ 170,083
Percentage allocated to common shareholders (as a percent)	99.70%	99.70%	99.70%	99.70%
Undistributed earnings allocated to common shareholders	$ 62,233	$ 83,026	$ 126,357	$ 169,573
Add: dividends declared - common shares	9,576	7,189	19,120	14,520
Numerator for basic and diluted earnings per common share	$ 71,809	$ 90,215	$ 145,477	$ 184,093
Denominator
Basic weighted average common shares outstanding (in shares)	95,641	89,846	95,370	90,832
Assumed conversion of dilutive stock-based compensation plans (in shares)	643	713	701	796
Denominator for diluted earnings per common share - adjusted weighted average shares and assumed conversion (in shares)	96,284	90,559	96,071	91,628
Net income attributable to Wabtec shareholders per common share
Basic (in dollars per share)	$ 0.75	$ 1.00	$ 1.52	$ 2.03
Diluted (in dollars per share)	$ 0.75	$ 1.00	$ 1.52	$ 2.02
Basic weighted-average common shares outstanding and non-vested restricted stock expected to vest (in shares)	95,917	90,101	95,666	91,111