Computation of Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011		Sep. 30, 2011		Jun. 30, 2011		Mar. 31, 2011		Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Components Of Basic And Diluted Earning Per Share [Line Items]
Numerator for basic and diluted earnings per common share-net income attributable to Wabtec shareholders	$ 64,765	$ 62,994	$ 64,712	$ 59,261	$ 46,263	[1]	$ 46,600	[1]	$ 36,334	[1]	$ 40,952	[1]	$ 251,732		$ 170,149		$ 123,099
Less: dividends declared-common shares and non-vested restricted stock													(7,666)		(3,849)		(1,914)
Undistributed earnings													244,066		166,300		121,185
Percentage allocated to common shareholders													99.50%	[2]	99.50%	[2]	99.50%	[2]
Undistributed earnings allocated to common shareholders													242,846		165,469		120,579
Add: dividends declared-common shares													7,627		3,830		1,905
Numerator for basic and diluted earnings per common share													$ 250,473		$ 169,299		$ 122,484
Denominator for basic earnings per common share-weighted-average shares													47,734		47,820		47,597
Assumed conversion of dilutive stock-based compensation plans													637		509		408
Denominator for diluted earnings per common share-adjusted weighted-average shares and assumed conversion													48,371		48,329		48,005
Basic	$ 1.35	$ 1.32	$ 1.35	$ 1.24	$ 0.96		$ 0.97		$ 0.75		$ 0.85		$ 5.24		$ 3.54		$ 2.57
Diluted	$ 1.34	$ 1.30	$ 1.33	$ 1.22	$ 0.96		$ 0.96		$ 0.75		$ 0.85		$ 5.19		$ 3.51		$ 2.56

[1] The second quarter of 2011 includes tax benefits of $1.7 million primarily related to resolving certain tax issues from prior periods that have been closed from further regulatory examination. The third quarter of 2012 includes tax benefits of $1.7 million due to claims for refund.

[2] Basic weighted-average common shares outstanding 47,734 47,820 47,597 Basic weighted-average common shares outstanding and non-vested restricted stock expected to vest 47,976 48,063 47,828 Percentage allocated to common shareholders 99.5 % 99.5 % 99.5 %