Sales by Product (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]
Total sales	$ 797,271	$ 631,398	$ 2,223,588	$ 1,884,910
Specialty Products & Electronics
Segment Reporting Information [Line Items]
Total sales	390,038	263,595	980,897	764,222
Brake Products
Segment Reporting Information [Line Items]
Total sales	170,826	137,189	487,095	417,921
Remanufacturing, Overhaul & Build
Segment Reporting Information [Line Items]
Total sales	142,620	161,857	474,444	489,391
Other Transit Products
Segment Reporting Information [Line Items]
Total sales	51,607	50,270	155,144	153,698
Other
Segment Reporting Information [Line Items]
Total sales	$ 42,180	$ 18,487	$ 126,008	$ 59,678