Income Taxes (Components Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Net operating loss carryforwards	$ 40,939	$ 42,060
Stock-based compensation	23,258	23,331
Employee benefits	17,044	20,034
Uncertain tax positions	10,233	8,545
Deferred revenue	8,603	6,533
Research and development credits	3,562	4,349
Allowance for doubtful accounts	1,888	1,806
Other	3,240	2,877
Valuation allowance	(603)	(130)
Deferred tax assets	108,164	109,405
Other intangible assets	(73,933)	(92,703)
Property and equipment	(3,426)	(4,652)
Deferred tax liabilities	(77,359)	(97,355)
Net deferred tax assets	$ 30,805	$ 12,050