Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Operating revenue	$ 265,482	$ 214,321	$ 204,710
Operating expenses:
Costs of services provided	72,437	47,388	40,471
Product development	30,702	26,860	26,798
Sales and marketing	14,917	13,840	15,848
General and administrative	48,078	36,880	36,480
Amortization and depreciation	10,634	9,681	10,107
Total operating expenses	176,768	134,649	129,704
Operating income	88,714	79,672	75,006
Interest income	231	379	518
Interest expense	(4,311)	(3,034)	(1,226)
Non-operating income - put options	0	296	342
Non-operating expense - securities litigation	0	(690)	(4,226)
Foreign exchange gain (loss)	2,005	829	(262)
Income before income taxes	86,639	77,452	70,152
Income tax provision	(7,106)	(13,894)	(10,878)
Net income	$ 79,533	$ 63,558	$ 59,274
Basic earnings per common share (in dollars per share)	$ 2.29	$ 1.68	$ 1.58
Diluted earnings per common share (in dollars per share)	$ 2.28	$ 1.67	$ 1.53
Basic weighted average shares outstanding (in shares)	34,668	37,809	37,588
Diluted weighted average shares outstanding (in shares)	34,901	38,040	38,642