EARNINGS PER SHARE - Computation of Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share [Abstract]
Net income attributable to Wabtec shareholders	$ 101,779	$ 99,181	$ 101,504	$ 96,164	$ 92,686	$ 90,155	$ 88,705	$ 80,134	$ 398,628	$ 351,680	$ 292,235
Less: dividends declared - common shares and non-vested restricted stock									(26,963)	(19,246)	(12,644)
Undistributed earnings									$ 371,665	$ 332,434	$ 279,591
Percentage allocated to common shareholders									99.70%	99.60%	99.50%
Undistributed earnings allocated to common shareholders									$ 370,550	$ 331,104	$ 278,193
Dividends Declared Common Shares									26,875	19,167	12,583
Numerator for basic and diluted earnings per common share									$ 397,425	$ 350,271	$ 290,776
Denominator for basic earnings per common share - weighted average shares (in shares)									96,074	95,781	95,463
Assumed conversion of dilutive stock-based compensation plans (in shares)									932	1,104	1,369
Denominator for diluted earnings per common shares - adjusted weighted average shares and assumed conversion (in shares)									97,006	96,885	96,832
Basic earnings per share, As reported (in dollars per share)	$ 1.06	$ 1.03	$ 1.05	$ 1.00	$ 0.96	$ 0.94	$ 0.92	$ 0.84	$ 4.14	$ 3.66	$ 3.05
Diluted earnings per share, As reported (in dollars per share)	$ 1.05	$ 1.02	$ 1.04	$ 0.99	$ 0.95	$ 0.93	$ 0.91	$ 0.83	$ 4.10	$ 3.62	$ 3.01
Basic weighted-average common shares outstanding and non-vested restricted stock expected to vest									96,388	96,175	95,932