Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Operating revenue	$ 199,370	$ 168,969	$ 132,188
Operating expenses:
Costs of services provided	38,133	33,589	29,599
Product development	24,825	19,208	13,607
Sales and marketing	16,687	13,642	6,372
General and administrative	33,562	26,268	24,065
Amortization and depreciation	9,155	7,514	6,038
Total operating expenses	122,362	100,221	79,681
Operating income	77,008	68,748	52,507
Interest income	441	557	519
Interest expense	(1,541)	(759)	(902)
Other non-operating income	190	647	6,319
Foreign exchange gain	1,931	4,302	1,211
Income before income taxes	78,029	73,495	59,654
Income tax provision	(7,460)	(2,117)	(635)
Net income	$ 70,569	$ 71,378	$ 59,019
Basic earnings per common share (in dollars per share)	$ 1.91	$ 1.89	$ 1.69
Diluted earnings per common share (in dollars per share)	$ 1.80	$ 1.75	$ 1.51
Basic weighted average shares outstanding (in shares)	36,948	37,742	34,845
Diluted weighted average shares outstanding (in shares)	39,100	40,889	39,018