Consolidated Statements of Stockholders' Equity (USD $) In Thousands, except Share data	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning Balance, Stockholders' equity at Dec. 31, 2009	$ 2,288,142	$ 35	$ 0	$ 1,634,754	$ 664,693	$ (11,340)
Beginning Balance, Treasury Shares at Dec. 31, 2009			0
Beginning Balance, Common Shares at Dec. 31, 2009		352,711,263
Exercise of common stock options	10,123	1	0	10,122	0	0
Exercise of common stock options, shares		2,255,318
Stock-based compensation expense	46,537	0	0	46,537	0	0
Restricted common stock vested and issued		589,903
Tax impact of stock-based award exercises and forfeitures	(4,652)	0	0	(4,652)	0	0
Purchase of treasury stock, shares		(237,818)	237,818
Purchase of treasury stock	(1,914)	0	(1,914)	0	0	0
Net income	193,415	0	0	0	193,415	0
Unrealized gains on available-for-sale securities, net of tax	361	0	0	0	0	361
Unrealized losses on cash flow hedging derivatives, net of tax	(7,268)	0	0	0	0	(7,268)
Reclassification adjustment for gains on available-for-sale securities included in net income, net of tax	(338)	0	0	0	0	338
Reclassification adjustment for losses on cash flow hedging derivatives included in net income, net of tax	17,170	0	0	0	0	(17,170)
Ending Balance, Stockholders' equity at Dec. 31, 2010	2,541,576	36	(1,914)	1,686,761	858,108	(1,415)
Ending Balance, Treasury Shares at Dec. 31, 2010			237,818
Ending Balance, Common Shares at Dec. 31, 2010		355,318,666
Exercise of common stock options	59,077	0	0	59,077	0	0
Exercise of common stock options, shares		6,370,790
Stock-based compensation expense	41,791	0	0	41,791	0	0
Restricted common stock vested and issued		1,136,002
Tax impact of stock-based award exercises and forfeitures	(3,356)	0	0	(3,356)	0	0
Purchase of treasury stock, shares		(365,063)	365,063
Purchase of treasury stock	(4,918)	0	(4,918)	0	0	0
Net income	301,310	0	0	0	301,310	0
Unrealized gains on available-for-sale securities, net of tax	212	0	0	0	0	212
Unrealized losses on cash flow hedging derivatives, net of tax	(22,145)	0	0	0	0	(22,145)
Reclassification adjustment for gains on available-for-sale securities included in net income, net of tax	(303)	0	0	0	0	303
Reclassification adjustment for losses on cash flow hedging derivatives included in net income, net of tax	14,356	0	0	0	0	(14,356)
Ending Balance, Stockholders' equity at Dec. 31, 2011	2,927,600	36	(6,832)	1,784,273	1,159,418	(9,295)
Ending Balance, Treasury Shares at Dec. 31, 2011	602,881		602,881
Ending Balance, Common Shares at Dec. 31, 2011	362,460,395	362,460,395
Exercise of common stock options	6,108	1	0	6,107	0	0
Exercise of common stock options, shares	996,325	996,325
Stock-based compensation expense	37,974	0	0	37,974	0	0
Restricted common stock vested and issued		1,490,273
Tax impact of stock-based award exercises and forfeitures	(3,328)	0	0	(3,328)	0	0
Purchase of treasury stock, shares		(454,356)	454,356
Purchase of treasury stock	(4,330)	0	(4,330)	0	0	0
Net income	394,172	0	0	0	394,172	0
Unrealized gains on available-for-sale securities, net of tax	3,661	0	0	0	0	3,661
Unrealized losses on cash flow hedging derivatives, net of tax	(6,153)	0	0	0	0	(6,153)
Reclassification adjustment for gains on available-for-sale securities included in net income, net of tax	(7,029)	0	0	0	0	7,029
Reclassification adjustment for losses on cash flow hedging derivatives included in net income, net of tax	9,214	0	0	0	0	(9,214)
Ending Balance, Stockholders' equity at Dec. 31, 2012	$ 3,358,907	$ 37	$ (11,162)	$ 1,826,044	$ 1,553,590	$ (9,602)
Ending Balance, Treasury Shares at Dec. 31, 2012	1,057,237		1,057,237
Ending Balance, Common Shares at Dec. 31, 2012	364,492,637	364,492,637