Consolidated Statements Of Comprehensive Income (Unaudited) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net income		$ 17,179	$ 39,903	$ 81,164	$ 130,886
Other comprehensive income, net of tax:
Changes in unrealized gains/(losses) on available-for-sale securities	[1],[2]	(611)	(3,884)	5,261	1,683
Changes in unrealized gains on cash flow hedging instruments	[2],[3]	(289)	1,108	199	2,094
Foreign currency translation adjustment	[2]	(2,935)	(8,388)	(1,620)	(6,320)
Total other comprehensive income/(loss), net of tax		(3,835)	(11,164)	3,840	(2,543)
Comprehensive income		13,344	28,739	85,004	128,343
Changes in unrealized gains (losses) on available-for-sale securities, tax		(2,400)	7,000	2,400	(1,600)
Reclassifications to earnings of realized gains on available-for-sale securities		200	700	2,100	1,900
Reclassifications to earnings of losses on cash flow hedging instruments		$ 900	$ 1,500	$ 3,100	$ 4,700

[1] Amounts are net of reclassifications to earnings of realized gains of $0.2 million and $0.7 million for the three months ended September 30, 2015 and 2014, respectively. Amounts are net of reclassifications to earnings of realized gains of $2.1 million and $1.9 million for the nine months ended September 30, 2015 and 2014, respectively.

[2] Net of tax benefit of $2.4 million and $7.0 million for the three months ended September 30, 2015 and 2014, respectively. Net of taxes of $2.4 million and a tax benefit of $1.6 million for the nine months ended September 30, 2015 and 2014, respectively.

[3] Amounts are net of reclassifications to earnings of losses of $0.9 million and $1.5 million for the three months ended September 30, 2015 and 2014, respectively. Amounts are net of reclassifications to earnings of losses of $3.1 million and $4.7 million for the nine months ended September 30, 2015 and 2014, respectively.