Business Combinations (Purchase Price Allocation) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	May 04, 2012 Convio, Inc [Member]
Business Acquisition [Line Items]
Net working capital, excluding deferred revenue			$ 57,062
Property and equipment			6,591
Other long term assets			75
Deferred revenue			(7,847)
Deferred tax liability			(33,181)
Intangible assets and liabilities			139,650
Goodwill	264,639	265,055	173,324
Total paid for acquisition			$ 335,674