Condensed Consolidated Statement of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 27,627	$ 31,650	$ 86,365	$ 91,377
Foreign currency translation adjustment, net of tax (benefit) of $759 and $(219) for the three and nine months of 2013, respectively, and $196 and $167 for the three and nine months of 2012, respectively	1,590	530	(526)	590
Unrealized gain (loss) on available-for-sale investments, net of tax (benefit) of $2,465 and $5,380 for the three and nine months of 2013, respectively, and ($877) and ($906) for the three and nine months of 2012, respectively	4,259	(1,515)	9,260	(1,365)
Other Comprehensive Income (Loss), Net of Tax	5,849	(985)	8,734	(775)
Comprehensive Income	33,668	30,665	95,537	90,602
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	33,476	30,665	95,099	90,602
Net Income (Loss) Attributable to Noncontrolling Interest	(179)	0	(403)	0
Foreign currency translation adjustment attributable to noncontrolling Interest, net of tax (benefit) of ($3) and ($20) for the three and nine months of 2013, respectively, and zero and zero for the three and six months of 2012 , respectively	$ (13)	$ 0	$ (35)	$ 0