Goodwill and Purchased Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Acquired Finite-Lived and Indefinite Intangible Assets [Line Items]
Gross Carrying Amount	$ 145,888				$ 108,736								$ 145,888	$ 108,736
Accumulated Amortization	79,717				58,013								79,717	58,013
Amortization	3,051	2,415	2,411	2,433	2,619	2,107	2,118	2,095	2,503	2,555	2,394	2,394	10,310	8,939	9,846
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2014	21,188												21,188
2015	14,195												14,195
2016	10,097												10,097
2017	7,673												7,673
2018	5,606												5,606
Thereafter	7,412												7,412
Total	66,171												66,171
Minimum
Acquired Finite-Lived and Indefinite Intangible Assets [Line Items]
Economic benefits intangible assets are expected to be realized													1 year
Maximum
Acquired Finite-Lived and Indefinite Intangible Assets [Line Items]
Economic benefits intangible assets are expected to be realized													15 years
Purchased technology
Acquired Finite-Lived and Indefinite Intangible Assets [Line Items]
Weighted Average Life (yrs)													7 years	8 years
Gross Carrying Amount	77,704				61,309								77,704	61,309
Accumulated Amortization	43,606				32,569								43,606	32,569
Purchased customer relationships
Acquired Finite-Lived and Indefinite Intangible Assets [Line Items]
Weighted Average Life (yrs)													7 years	7 years
Gross Carrying Amount	49,446				30,729								49,446	30,729
Accumulated Amortization	21,477				13,991								21,477	13,991
Purchased backlog
Acquired Finite-Lived and Indefinite Intangible Assets [Line Items]
Weighted Average Life (yrs)													3 years	3 years
Gross Carrying Amount	9,506				7,800								9,506	7,800
Accumulated Amortization	8,022				6,370								8,022	6,370
Purchased contract base
Acquired Finite-Lived and Indefinite Intangible Assets [Line Items]
Weighted Average Life (yrs)													5 years	5 years
Gross Carrying Amount	50				50								50	50
Accumulated Amortization	50				50								50	50
Purchased intellectual property
Acquired Finite-Lived and Indefinite Intangible Assets [Line Items]
Weighted Average Life (yrs)													5 years	5 years
Gross Carrying Amount	1,998				1,998								1,998	1,998
Accumulated Amortization	1,998				1,860								1,998	1,860
Purchased trademark/tradename
Acquired Finite-Lived and Indefinite Intangible Assets [Line Items]
Weighted Average Life (yrs)													6 years	5 years
Gross Carrying Amount	7,184				6,850								7,184	6,850
Accumulated Amortization	4,564				3,173								4,564	3,173
Purchased trademark/tradename
Acquired Finite-Lived and Indefinite Intangible Assets [Line Items]
Purchased trademark/tradename	$ 2,500				$ 2,500								$ 2,500	$ 2,500