Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Net income	$ 191,729	$ 220,158	$ 383,165	$ 345,970
Changes in market value of available-for-sale securities:
Unrealized gains (losses), net of taxes of $(96), $1,352, $1,028 and $1,196	(157)	2,029	1,677	1,794
Reclassification of (gains) losses recognized during the period, net of taxes of $(283), $(22,494), $53 and $(12,788)	(461)	(33,742)	86	(19,181)
Net change in market value of available-for-sale securities	(618)	(31,713)	1,763	(17,387)
Changes in market value of effective foreign currency forward exchange contracts:
Unrealized gains (losses), net of taxes of $10, $0, $10 and $0	194	0	194	0
Reclassification of (gains) losses recognized during the period, net of taxes of $(40), $0, $10 and $0	(728)	0	50	0
Net change in market value of effective foreign currency forward exchagne contracts	(534)	0	244	0
Total other comprehensive income	(1,152)	(31,713)	2,007	(17,387)
Total comprehensive income, net of taxes	$ 190,577	$ 188,445	$ 385,172	$ 328,583