Acquistions Acquisition Consideration for Continuous Computing (Details) (USD $)	Jul. 08, 2011	Dec. 31, 2012 Continuous Computing [Member]	Jul. 08, 2011 Continuous Computing [Member]	Dec. 31, 2012 Estimate of Fair Value, Fair Value Disclosure [Member] Fair Value, Measurements, Recurring [Member]	Dec. 31, 2011 Estimate of Fair Value, Fair Value Disclosure [Member] Fair Value, Measurements, Recurring [Member]	Jul. 08, 2011 Estimate of Fair Value, Fair Value Disclosure [Member] Fair Value, Measurements, Recurring [Member] Continuous Computing [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Cash Paid, Aggregate Cash Amount		$ 73,000,000	$ 73,000,000
Business Acquisition, Cost of Acquired Entity, Cash Paid, Working Capital Adjustment		8,500,000	8,500,000
Obligations, Fair Value Disclosure				(2,541,000)	(7,594,000)	7,400,000
Business Acquisition, Cost of Acquired Entity, Fair Value at Date of Purchase			30,800,000
Business Acquisition, Cost of Acquired Entity, Fair Value of Stock Options Assumed	65,000
Business Acquisition, Cost of Acquired Entity, Purchase Price	$ 119,731,000	$ 119,731,000