Condensed Consolidated Statement Of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities:
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 98,169	$ 92,573
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	63,635	43,307
Amortization of discount or premium of investments	871	983
Amortization of financing costs and discounts	6,774	2,828
Share-based compensation	8,943	6,538
Excess tax benefits from share-based compensation	(4,541)	(6,728)
Provision for doubtful accounts	5,015	3,278
Deferred income taxes	219	(2,954)
(Gain) loss on sale of available-for-sale investments	(37)	(69)
Decrease (increase) in:
Accounts receivable	(4,296)	1,267
Prepaid expenses and other current assets	2,815	(4,124)
Other assets	(77)	(128)
(Decrease) increase in:
Accounts payable and accrued expenses	(5,783)	(2,949)
Income taxes payable	(13,565)	7,565
Deferred revenue	(3,727)	(815)
Liability for uncertain tax positions	(9,916)	(8,071)
Other	4,074	(380)
Net cash provided by operating activities	148,573	132,121
Cash flows from investing activities:
Maturity of certificates of deposit	65	14,520
Purchase of certificates of deposit	(62)	0
Sales of available-for-sale investments	87,976	60,456
Purchase of available-for-sale investments	(78,281)	(112,983)
Purchases of property and equipment	(11,927)	(7,755)
Proceeds from sale of assets	0	608
Acquisition of businesses, net of cash received	(259,838)	(118,238)
Purchases of intangible assets	(1,258)	(4,806)
Net cash used in investing activities	(263,325)	(168,198)
Cash flows from financing activities:
Proceeds from Issuance of Long-term Debt	0	402,500
Payments of Debt Issuance Costs	0	11,527
Repurchases of common stock and restricted stock	(3,159)	(5,473)
Issuance of common stock under employee stock purchase plan	196	199
Exercise of stock options	4,618	6,387
Dividends paid	(43,526)	(38,547)
Excess tax benefits from share-based compensation	4,541	6,728
Deferred payments for acquisitions	(5,411)	(14,316)
Proceeds from (Payments for) Other Financing Activities	(250)	(711)
Net cash used in financing activities	(42,991)	345,240
Effect of exchange rate changes on cash and cash equivalents	(3,552)	(1,967)
Net change in cash and cash equivalents	(161,295)	307,196
Cash and cash equivalents	272,368	514,997
Cash and cash equivalents at end of period	$ 272,368	$ 514,997