Goodwill and Other Intangible Assets (Schedule of Other Intangible Assets) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Sep. 30, 2012 Y	Dec. 31, 2011 Y
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 187,661	$ 135,061
Accumulated amortization	(105,286)	(89,675)
Net carrying amount	82,375	45,386
Completed Technologies [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	66,931	36,731
Accumulated amortization	(30,229)	(22,913)
Net carrying amount	36,702	13,818
Finite-Lived Intangible Assets, Weighted-Average Useful Life (in years)	6	6
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	102,100	88,700
Accumulated amortization	(66,657)	(60,202)
Net carrying amount	35,443	28,498
Finite-Lived Intangible Assets, Weighted-Average Useful Life (in years)	9	9
Non-Compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	14,440	8,340
Accumulated amortization	(6,999)	(5,270)
Net carrying amount	7,441	3,070
Weighted average amortization period (in years)	5	4
Trademarks and Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	3,700	800
Accumulated amortization	(911)	(800)
Net carrying amount	2,789	0
Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period (in years)	9	4
Acquired License Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	490	490
Accumulated amortization	(490)	(490)
Net carrying amount	$ 0	$ 0
acquired license rights [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period (in years)	10	10