Deferred Revenue (Schedule Of Deferred Revenue) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Deferred Revenue Arrangement [Line Items]
Current deferred revenue	$ 80,568	$ 73,840
Long-term deferred revenue	13,609	15,367
Total deferred revenue	94,177	89,207
Software License [Member]
Deferred Revenue Arrangement [Line Items]
Current deferred revenue	14,026	15,005
Long-term deferred revenue	12,378	13,532
Maintenance [Member]
Deferred Revenue Arrangement [Line Items]
Current deferred revenue	60,012	50,916
Professional Services And Other [Member]
Deferred Revenue Arrangement [Line Items]
Current deferred revenue	6,530	7,919
Maintenance And Professional Services [Member]
Deferred Revenue Arrangement [Line Items]
Long-term deferred revenue	$ 1,231	$ 1,835