Guarantor Subsidiaries Financial Information - Condensed Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 1,077,814	$ 957,931	$ 3,245,671	$ 2,806,218
Cost of sales	(775,802)	(704,728)	(2,308,811)	(2,009,345)
Gross profit	302,012	253,203	936,860	796,873
Total operating expenses	(176,833)	(151,537)	(556,879)	(467,338)
Income from operations	125,179	101,666	379,981	329,535
Interest (expense) income, net	(23,713)	(20,038)	(75,917)	(57,460)
Other income (expense), net	1,201	(443)	5,958	5,304
Equity earnings (loss)	0	0	0	0
Income from operations before income taxes	102,667	81,185	310,022	277,379
Income tax expense	(16,598)	(12,746)	(53,225)	(64,776)
Net income	86,069	68,439	256,797	212,603
Less: Net loss (gain) attributable to noncontrolling interest	1,670	(1,040)	3,724	710
Net income attributable to Wabtec shareholders	87,739	67,399	260,521	213,313
Comprehensive income attributable to Wabtec shareholders	38,207	160,019	99,780	500,988
Elimination
Condensed Financial Statements, Captions [Line Items]
Net sales	(60,397)	(28,421)	(178,943)	(85,791)
Cost of sales	34,238	15,557	105,071	59,386
Gross profit	(26,159)	(12,864)	(73,872)	(26,405)
Total operating expenses	0	0	0	0
Income from operations	(26,159)	(12,864)	(73,872)	(26,405)
Interest (expense) income, net	0	0	0	0
Other income (expense), net	0	0	0	0
Equity earnings (loss)	(188,886)	(145,694)	(635,205)	(428,169)
Income from operations before income taxes	(215,045)	(158,558)	(709,077)	(454,574)
Income tax expense	0	0	0	0
Net income	(215,045)	(158,558)	(709,077)	(454,574)
Less: Net loss (gain) attributable to noncontrolling interest	0	0	0	0
Net income attributable to Wabtec shareholders	(215,045)	(158,558)	(709,077)	(454,574)
Comprehensive income attributable to Wabtec shareholders	(215,045)	(158,558)	(709,077)	(454,574)
Parent
Condensed Financial Statements, Captions [Line Items]
Net sales	169,445	134,905	499,172	417,156
Cost of sales	(122,946)	(111,774)	(364,523)	(311,037)
Gross profit	46,499	23,131	134,649	106,119
Total operating expenses	(37,090)	(22,886)	(122,497)	(80,478)
Income from operations	9,409	245	12,152	25,641
Interest (expense) income, net	(23,012)	(20,295)	(75,140)	(55,783)
Other income (expense), net	(1,479)	1,520	7,733	6,863
Equity earnings (loss)	97,128	80,874	330,978	246,103
Income from operations before income taxes	82,046	62,344	275,723	222,824
Income tax expense	5,693	5,056	(15,202)	(9,511)
Net income	87,739	67,400	260,521	213,313
Less: Net loss (gain) attributable to noncontrolling interest	0	0	0	0
Net income attributable to Wabtec shareholders	87,739	67,400	260,521	213,313
Comprehensive income attributable to Wabtec shareholders	87,867	66,815	261,156	214,483
Guarantors
Condensed Financial Statements, Captions [Line Items]
Net sales	118,516	89,881	374,599	288,312
Cost of sales	(75,021)	(53,692)	(236,699)	(177,593)
Gross profit	43,495	36,189	137,900	110,719
Total operating expenses	(14,746)	(12,714)	(40,687)	(37,783)
Income from operations	28,749	23,475	97,213	72,936
Interest (expense) income, net	3,212	2,811	9,291	8,041
Other income (expense), net	1	0	(678)	(229)
Equity earnings (loss)	91,758	64,820	304,227	182,066
Income from operations before income taxes	123,720	91,106	410,053	262,814
Income tax expense	(2)	0	(2)	0
Net income	123,718	91,106	410,051	262,814
Less: Net loss (gain) attributable to noncontrolling interest	0	0	0	0
Net income attributable to Wabtec shareholders	123,718	91,106	410,051	262,814
Comprehensive income attributable to Wabtec shareholders	123,718	91,106	410,051	262,814
Non-Guarantors
Condensed Financial Statements, Captions [Line Items]
Net sales	850,250	761,566	2,550,843	2,186,541
Cost of sales	(612,073)	(554,819)	(1,812,660)	(1,580,101)
Gross profit	238,177	206,747	738,183	606,440
Total operating expenses	(124,997)	(115,937)	(393,695)	(349,077)
Income from operations	113,180	90,810	344,488	257,363
Interest (expense) income, net	(3,913)	(2,554)	(10,068)	(9,718)
Other income (expense), net	2,679	(1,963)	(1,097)	(1,330)
Equity earnings (loss)	0	0	0	0
Income from operations before income taxes	111,946	86,293	333,323	246,315
Income tax expense	(22,289)	(17,802)	(38,021)	(55,265)
Net income	89,657	68,491	295,302	191,050
Less: Net loss (gain) attributable to noncontrolling interest	1,670	(1,040)	3,724	710
Net income attributable to Wabtec shareholders	91,327	67,451	299,026	191,760
Comprehensive income attributable to Wabtec shareholders	$ 41,667	$ 160,656	$ 137,650	$ 478,265