Goodwill and Other Intangible Assets (Changes in Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2010
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, Ending Gross Amount	$ 290,496	$ 280,445
Finite-lived intangible assets, Accumulated Amortization	(173,522)	(157,819)
Indefinite-lived intangible assets, Ending Gross Amount	94,665	93,475
Indefinite-lived intangible assets, Accumulated Amortization	(1,590)	$ (1,573)
Minimum
Finite-Lived Intangible Assets [Line Items]
Useful Life (Years)		4 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Life (Years)		40 years
Engineering drawings
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, Ending Gross Amount	90,442	$ 92,135
Finite-lived intangible assets, Accumulated Amortization	$ (71,761)	(69,881)
Engineering drawings | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful Life (Years)	10 years
Engineering drawings | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Life (Years)	22 years
Existing customer relationships
Finite-Lived Intangible Assets [Line Items]
Useful Life (Years)			5 years
Finite-lived intangible assets, Ending Gross Amount	$ 84,291	78,610
Finite-lived intangible assets, Accumulated Amortization	$ (41,279)	(31,671)
Existing customer relationships | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful Life (Years)	5 years
Existing customer relationships | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Life (Years)	10 years
Patents
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, Ending Gross Amount	$ 26,876	26,529
Finite-lived intangible assets, Accumulated Amortization	$ (26,231)	(25,318)
Patents | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful Life (Years)	9 years
Patents | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Life (Years)	16 years
Other
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, Ending Gross Amount	$ 88,887	83,171
Finite-lived intangible assets, Accumulated Amortization	$ (34,251)	$ (30,949)
Other | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful Life (Years)	4 years
Other | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Life (Years)	40 years