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	$ 1,424,037	$ 1,059,131	$ 528,142
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	32,818	20,648	16,209
Amortization	32,323	33,176	34,255
Provision for uncollectible accounts, net	16,094	9,331	7,102
Deferred income tax expense	19,596	44,747	37,540
Stock-based compensation and other stock based payments	72,035	66,194	68,396
Amortization of debt issuance costs	5,212	2,360	3,332
Amortization of debt discount	39,820	21,414	20,110
Loss on early extinguishment of debt	0	32	11,334
Changes in assets and liabilities:
Accounts receivable	(105,277)	(125,793)	(29,275)
Prepaid expenses and other current assets	(40,793)	12,213	(22,373)
Accounts payable, accrued expenses and other current liabilities	256,021	210,325	84,750
Other	33,864	(11,966)	17,775
Net cash provided by operating activities	1,785,750	1,341,812	777,297
INVESTING ACTIVITIES:
Purchase of investments	(6,352,495)	(3,005,397)	(1,813,032)
Proceeds from sale of investments	4,799,412	2,229,563	1,071,669
Additions to property and equipment	(55,158)	(46,833)	(22,593)
Acquisitions and other equity investments, net of cash acquired	(33,861)	(68,192)	(112,405)
Proceeds from foreign currency contracts	86,159	31,045	44,564
Payments on foreign currency contracts	(4,014)	(42,032)	(9,561)
Change in restricted cash	(2,756)	(2,922)	260
Net cash used in investing activities	(1,562,713)	(904,768)	(841,098)
FINANCING ACTIVITIES:
Proceeds from the issuance of convertible senior notes	1,000,000		575,000
Payment of debt issuance costs	(20,916)		(13,334)
Payments related to conversion of senior notes	(1)	(213)	(295,401)
Repurchase of common stock	(257,021)	(163,171)	(129,445)
Payments to purchase subsidiary shares from noncontrolling interests	(61,079)	(12,986)	0
Proceeds from the sale of subsidiary shares to noncontrolling interests	0		4,311
Proceeds from exercise of stock options	2,683	4,302	25,751
Proceeds from the termination of conversion spread hedges	0		42,984
Excess tax benefit from stock-based compensation	5,189	21,041	3,091
Net cash provided by (used in) financing activities	668,855	(151,027)	212,957
Effect of exchange rate changes on cash and cash equivalents	11,621	(12,148)	7,670
Net increase in cash and cash equivalents	903,513	273,869	156,826
Cash and cash equivalents, beginning of period	632,836	358,967	202,141
Cash and cash equivalents, end of period	1,536,349	632,836	358,967
SUPPLEMENTAL CASH FLOW INFORMATION:
Cash paid during the period for income taxes	300,539	232,762	169,320
Cash paid during the period for interest	13,933	7,573	4,901
Non-cash fair value increase for redeemable noncontrolling interests	$ 84,693	$ 91,743	$ 7,876