Segment Information (Supplemental Disclosure Of Revenue By Service Type) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Transaction services revenue	$ 71,645,000	$ 57,493,000	$ 133,009,000	$ 111,633,000
Subscription services revenue	44,623,000	33,932,000	87,401,000	67,213,000
Other	5,514,000	4,971,000	10,431,000	9,167,000
Net revenue	121,782,000	96,396,000	230,841,000	188,013,000
Canada [Member]
Segment Reporting Information [Line Items]
Percentage of Revenue earned in Canada	10.00%	11.00%	10.00%	10.00%
Long-lived assets	$ 41,300,000		$ 41,300,000		$ 44,800,000