Segment Information (Supplemental Disclosure Of Revenue By Service Type) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Segment Reporting Information [Line Items]
Transaction services revenue	$ 184,892,000	$ 102,000,000	$ 94,406,000
Subscription services revenue	146,621,000	123,547,000	114,931,000
Other	21,781,000	18,279,000	16,289,000
Total net revenue	353,294,000	243,826,000	225,626,000
Foreign Countries [Member]
Segment Reporting Information [Line Items]
Long-lived assets	$ 35,500,000	$ 37,100,000
Foreign Countries [Member] | Sales [Member]
Segment Reporting Information [Line Items]
Percentage of revenue from outside the United States	9.00%	12.00%	11.00%