Investment Securities (Details 5) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Fair value of marketable securities
Total	$ 1,135,865us-gaap_AvailableForSaleSecurities	$ 1,150,815us-gaap_AvailableForSaleSecurities
Corporate Bonds
Fair value of marketable securities
Debt security	1,052,390	1,049,139
Other
Fair value of marketable securities
Debt security	41,513	59,971
Level 3
Fair value of marketable securities
Fair value of investments	0	0
Fair value measurements on recurring basis \| Total
Fair value of marketable securities
Cash equivalents (including restricted)	493,842	437,886
Total	1,135,865	1,150,815
Fair value measurements on recurring basis \| Total \| Corporate Bonds
Fair value of marketable securities
Debt security	1,052,390	1,049,139
Fair value measurements on recurring basis \| Total \| Other
Fair value of marketable securities
Debt security	41,513	59,971
Fair value measurements on recurring basis \| Total \| Strategic equity securities
Fair value of marketable securities
Equity security	41,962	41,705
Fair value measurements on recurring basis \| Level 1
Fair value of marketable securities
Cash equivalents (including restricted)	122,072	58,108
Total	47,562	47,335
Fair value measurements on recurring basis \| Level 1 \| Other
Fair value of marketable securities
Debt security	5,600	5,630
Fair value measurements on recurring basis \| Level 1 \| Strategic equity securities
Fair value of marketable securities
Equity security	41,962	41,705
Fair value measurements on recurring basis \| Level 2
Fair value of marketable securities
Cash equivalents (including restricted)	371,770	379,778
Total	1,088,303	1,103,480
Fair value measurements on recurring basis \| Level 2 \| Corporate Bonds
Fair value of marketable securities
Debt security	1,052,390	1,049,139
Fair value measurements on recurring basis \| Level 2 \| Other
Fair value of marketable securities
Debt security	$ 35,913	$ 54,341

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

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