Income Taxes Income Taxes (Schedule of Deferred Tax and Related Valuation Allowance) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Net operating loss and credit carryforwards	$ 15,655	$ 9,323
Depreciation and amortization	5,495	30,702
Compensation costs	45,974	35,959
Other	18,542	15,530
Deferred tax assets	85,666	91,514
Acquired intangible assets not deductible	(26,293)	(16,972)
Internal-use software capitalized	(24,301)	(24,165)
Impairment loss on marketable securities	0	(15)
Deferred tax liabilities	(50,594)	(41,152)
Valuation allowance	(430)	(433)
Net deferred tax assets	$ 34,642	$ 49,929