Goodwill And Intangible Assets (Summary Of Intangible Assets) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Acquired Finite-Lived Intangible Assets [Line Items]
Document Period End Date	Mar. 31, 2013
Weighted Average Amortization Period of Finite Lived Assets (in years)	14 years
Gross Asset	$ 285,887	$ 291,106
Accumulated Amortization	167,322	165,193
Net	118,565	125,913
Finite-Lived Intangible Assets, Net	118,565	125,913	146,227
Intellectual Property Rights
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period of Finite Lived Assets (in years)	18 years 9 months 18 days
Gross Asset	87,234	88,614
Accumulated Amortization	47,120	47,202
Net	40,114	41,412
Customer Relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period of Finite Lived Assets (in years)	11 years 7 months 6 days
Gross Asset	137,123	140,250
Accumulated Amortization	75,173	73,630
Net	61,950	66,620
Drawings
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period of Finite Lived Assets (in years)	37 years 10 months 24 days
Gross Asset	11,149	11,149
Accumulated Amortization	9,875	9,850
Net	1,274	1,299
Other Intangible Assets
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period of Finite Lived Assets (in years)	14 years
Gross Asset	50,381	51,093
Accumulated Amortization	35,154	34,511
Net	$ 15,227	$ 16,582