Condensed Consolidated Statements of Cash Flows - Unaudited (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net income	$ 42,270	$ 33,089
Adjustments to reconcile net income to net cash provided by operating activities-
Depreciation	14,379	17,084
Amortization	28,413	33,294
Amortization of original issue discount	3,975	3,680
Impairment of client contract		2,500
(Gain) loss on short-term investments and other	1,264	(46)
Deferred income taxes	1,083	(7,789)
Excess tax benefit of stock-based compensation awards	(619)	(406)
Stock-based employee compensation	11,497	9,990
Changes in operating assets and liabilities:
Trade accounts receivable, net	75	13,358
Other current and non-current assets	(4,641)	(2,293)
Income taxes payable/receivable	1,359	(151)
Trade accounts payable and accrued liabilities	(15,724)	(92)
Deferred revenue	3,251	6,204
Net cash provided by operating activities	86,582	108,422
Cash flows from investing activities:
Purchases of property and equipment	(18,986)	(20,488)
Purchases of short-term investments	(129,259)	(45,499)
Proceeds from sale/maturity of short-term investments	62,720	33,152
Acquisition of business, net of cash acquired		(19,085)
Acquisition of and investments in client contracts	(5,349)	(4,253)
Proceeds from disposition of business	1,734
Net cash used in investing activities	(89,140)	(56,173)
Cash flows from financing activities:
Proceeds from issuance of common stock	1,283	1,572
Repurchase of common stock	(15,124)	(16,323)
Payment of cash dividends	(9,630)
Payments on acquired equipment financing	(1,894)	(765)
Payments on long-term debt	(11,250)	(22,000)
Excess tax benefit of stock-based compensation awards	619	406
Net cash used in financing activities	(35,996)	(37,110)
Effect of exchange rate fluctuations on cash	(2,457)	(1,564)
Net increase (decrease) in cash and cash equivalents	(41,011)	13,575
Cash and cash equivalents, beginning of period	133,747	146,733
Cash and cash equivalents, end of period	92,736	160,308
Net cash paid during the period for-
Interest	8,247	11,193
Income taxes	$ 3,554	$ 33,196