Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Operating activities:
Net income	$ 165,903	$ 136,902	$ 96,285
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of intangibles	29,771	32,064	35,874
Stock-based compensation expense	36,378	32,865	32,634
Excess tax benefits from employee stock-based compensation exercises	(21,304)	(25,572)	(18,364)
Deferred taxes	973	(965)	(2,609)
Amortization and write-off of debt issue costs	2,008	2,288	1,567
Changes in assets and liabilities:
Fees receivable, net	(38,617)	(58,887)	(48,177)
Deferred commissions	(8,871)	(6,928)	(2,184)
Prepaid expenses and other current assets	(10,604)	3,540	(376)
Other assets	15,113	4,397	(34,130)
Deferred revenues	71,645	91,765	85,336
Accounts payable, accrued, and other liabilities	37,418	44,097	59,643
Cash provided by operating activities	279,813	255,566	205,499
Investing activities:
Additions to property, equipment and leasehold improvements	(44,337)	(41,954)	(21,694)
Acquisitions (net of cash received)	(10,336)		(12,151)
Cash used in investing activities	(54,673)	(41,954)	(33,845)
Financing activities:
Proceeds from employee stock-based compensation plans and ESP Plan	12,430	20,011	23,527
Proceeds from borrowings	35,000		200,000
Payments on debt	(30,000)	(20,156)	(313,627)
Purchases of treasury stock	(111,304)	(211,986)	(99,820)
Excess tax benefits from employee stock-based compensation exercises	21,304	25,572	18,364
Cash used by financing activities	(72,570)	(186,559)	(171,556)
Net increase in cash and cash equivalents	152,570	27,053	98
Effects of exchange rates on cash and cash equivalents	4,543	(4,495)	3,509
Cash and cash equivalents, beginning of period	142,739	120,181	116,574
Cash and cash equivalents, end of period	299,852	142,739	120,181
Cash paid during the period for:
Interest	8,968	13,312	11,484
Income taxes, net of refunds received	$ 46,907	$ 24,126	$ 25,486