Consolidated Statement Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 107,522	$ 121,663	$ 114,766
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	39,788	22,164	19,756
Amortization of discount or premium of investments	(1,796)	(1,603)	(941)
Amortization of financing costs and discounts	613	249	0
Share-based compensation	9,720	9,132	8,968
Excess tax benefits from share-based compensation	2,695	961	13,561
Provision for doubtful accounts	3,135	4,289	6,900
Deferred income taxes	250	1,150	6,822
Loss on disposal of fixed assets	8	54	117
(Gain) loss on available-for-sale investments	66	(266)	(552)
Loss on extinguishment of debt and related interest expense	14,437	0	0
Decrease (increase) in:
Accounts receivable	9,588	5,417	9,509
Prepaid expenses and other current assets	(149)	2,028	(4,261)
Other assets	(168)	243	(204)
(Decrease) increase in:
Accounts payable and accrued expenses	9,126	5,138	847
Income taxes payable	667	4,139	9,679
Deferred revenue	12,368	1,612	8,664
Liability for uncertain tax positions	6,186	7,601	(7,786)
Other	(392)	32	231
Net cash provided by operating activities	193,324	169,911	150,748
Cash flows from investing activities:
Maturity of certificates of deposit	42,615	8,000	0
Purchase of certificates of deposit	(22,071)	(34,673)	(8,000)
Sales of available-for-sale investments	140,126	138,709	29,777
Purchase of available-for-sale investments	(168,901)	(151,989)	(82,879)
Purchases of property and equipment	(18,627)	(5,061)	(6,844)
Proceeds from sale of assets	1	156	4
Acquisition of businesses, net of cash received	(126,341)	(198,341)	(3,926)
Purchases of intangible assets	(14,200)	(6,295)	(4,312)
Net cash used in investing activities	(167,398)	(249,494)	(76,180)
Cash flows from financing activities:
Issuance of long-term debt	0	245,000	0
Debt issuance costs	(47)	(1,384)	0
Repurchases of common stock and restricted stock	(4,587)	(60,282)	(1,281)
Issuance of common stock under employee stock purchase plan	213	157	142
Exercise of stock options	13,604	5,646	7,090
Proceeds from noncontrolling interests	0	8,557	0
Dividends paid	(45,134)	(40,263)	(19,174)
Excess tax benefits from share-based compensation	2,695	961	13,561
Proceeds from (Payments for) Other Financing Activities	(2,437)	0	0
Net cash (used in) provided by financing activities	(35,693)	158,392	338
Effect of exchange rate changes on cash and cash equivalents	(1,112)	512	(299)
Net change in cash and cash equivalents	(10,879)	79,321	74,607
Cash and cash equivalents at beginning of period	218,680	139,359	64,752
Cash and cash equivalents at end of period	$ 207,801	$ 218,680	$ 139,359