Deferred Revenue (Schedule Of Deferred Revenue) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Deferred Revenue Arrangement [Line Items]
Current deferred revenue	$ 73,840	$ 56,903
Long-term deferred revenue	15,367	17,751
Total deferred revenue	89,207	74,654
Software License [Member]
Deferred Revenue Arrangement [Line Items]
Current deferred revenue	15,005	7,617
Long-term deferred revenue	13,532	15,833
Maintenance Revenues [Member]
Deferred Revenue Arrangement [Line Items]
Current deferred revenue	50,916	43,594
Professional Services And Other [Member]
Deferred Revenue Arrangement [Line Items]
Current deferred revenue	7,919	5,692
Maintenance And Professional Services [Member]
Deferred Revenue Arrangement [Line Items]
Long-term deferred revenue	$ 1,835	$ 1,918