Goodwill and Other Intangible Assets (Schedule of Intangible Assets) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Goodwill, impairment loss	$ 0	$ 0
Gross	254,565		253,700
Accumulated Amortization	(155,618)		(149,791)
Intangible assets, Net	98,947		103,909
Weighted-Average Useful Life (years)	10 years		10 years
Intellectual Property [Member]
Finite-Lived Intangible Assets [Line Items]
Gross	29,778		29,477
Accumulated Amortization	(23,973)		(23,128)
Intangible assets, Net	5,805		6,349
Weighted-Average Useful Life (years)	9 years		9 years
Customer Related Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross	141,991		141,833
Accumulated Amortization	(77,361)		(74,311)
Intangible assets, Net	64,630		67,522
Weighted-Average Useful Life (years)	12 years		12 years
Supplier Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross	240		240
Accumulated Amortization	(111)		(108)
Intangible assets, Net	129		132
Weighted-Average Useful Life (years)	20 years		20 years
Technology-Based Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross	80,870		80,489
Accumulated Amortization	(52,567)		(50,673)
Intangible assets, Net	28,303		29,816
Weighted-Average Useful Life (years)	9 years		9 years
Non-competition Agreement [Member]
Finite-Lived Intangible Assets [Line Items]
Gross	1,686		1,661
Accumulated Amortization	(1,606)		(1,571)
Intangible assets, Net	$ 80		$ 90
Weighted-Average Useful Life (years)	4 years		4 years