Acquisition (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Aug. 31, 2012
Business Acquisition [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired		100.00%
Business Acquisition, Cost of Acquired Entity, Purchase Price		$ 39,000
Business Acquisition, Contingent Consideration, Potential Cash Payment		15,000
Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets		16,000
Business Acquisition, Purchase Price Allocation, Goodwill Amount		26,000
Historical annual revenue of acquired company	14,000
Short-Term Liabilities
Business Acquisition [Line Items]
Business Acquisition, Contingent Consideration, Potential Cash Payment		3,000
Long-Term Liabililites
Business Acquisition [Line Items]
Business Acquisition, Contingent Consideration, Potential Cash Payment		$ 12,000