Condensed Consolidated Statement Of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities:
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 92,573	$ 86,365
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	43,307	28,424
Amortization of discount or premium of investments	983	1,323
Amortization of financing costs and discounts	2,828	456
Share-based compensation	6,538	7,108
Excess tax benefits from share-based compensation	(6,728)	(3,171)
Provision for doubtful accounts	3,278	2,565
Deferred income taxes	(2,954)	472
(Gain) loss on sale of available-for-sale investments	(69)	103
Decrease (increase) in:
Accounts receivable	1,267	(7,495)
Prepaid expenses and other current assets	(4,124)	945
Other assets	(128)	182
(Decrease) increase in:
Accounts payable and accrued expenses	(2,949)	4,035
Income taxes payable	7,565	(3,286)
Deferred revenue	(815)	13,049
Liability for uncertain tax positions	(8,071)	3,867
Other	(380)	(62)
Net cash provided by operating activities	132,121	134,880
Cash flows from investing activities:
Maturity of certificates of deposit	14,520	42,615
Purchase of certificates of deposit	0	(22,071)
Sales of available-for-sale investments	60,456	82,889
Purchase of available-for-sale investments	(112,983)	(139,955)
Purchases of property and equipment	(7,755)	(11,116)
Proceeds from sale of assets	608	1
Acquisition of businesses, net of cash received	(118,238)	(81,566)
Purchases of intangible assets	(4,806)	(2,784)
Net cash used in investing activities	(168,198)	(131,987)
Cash flows from financing activities:
Proceeds from Issuance of Long-term Debt	402,500	0
Debt issuance costs	(11,527)	(47)
Repurchases of common stock and restricted stock	(5,473)	(4,513)
Issuance of common stock under employee stock purchase plan	199	161
Exercise of stock options	6,441	13,515
Dividends paid	(38,547)	(33,267)
Excess tax benefits from share-based compensation	6,728	3,171
Deferred payments for acquisitions	(14,316)	0
Proceeds from (Payments for) Other Financing Activities	(765)	(171)
Net cash used in financing activities	345,240	(21,151)
Effect of exchange rate changes on cash and cash equivalents	(1,967)	(1,241)
Net change in cash and cash equivalents	307,196	(19,499)
Cash and cash equivalents	514,997
Cash and cash equivalents at end of period	$ 514,997