Computation of Basic and Diluted Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Earnings Per Share Basic And Diluted By Common Class [Line Items]
Net income attributable to Wabtec shareholders	$ 69,613		$ 59,261
Less: dividends declared—common shares and non-vested restricted stock	(2,386)		(1,438)
Undistributed earnings	67,227		57,823
Percentage allocated to common shareholders	99.50%	[1]	99.50%	[1]
Undistributed earnings allocated to common shareholders	66,891		57,534
Add: dividends declared—common shares	2,374		1,430
Numerator for basic and diluted earnings per common share	$ 69,265		$ 58,964
Denominator for basic earnings per common share—weighted-average shares	47,512		47,707
Assumed conversion of dilutive stock-based compensation plans	774		634
Denominator for diluted earnings per common share—adjusted weighted-average shares and assumed conversion	48,286		48,341
Basic	$ 1.46		$ 1.24
Diluted	$ 1.44		$ 1.22

[1] (1) Basic weighted-average common shares outstanding47,51247,707 Basic weighted-average common shares outstanding and non-vested restricted stock expected to vest47,75047,962 Percentage allocated to common shareholders99.5%99.5%