Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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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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Amount of investment in marketable security.

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Marketable Investment Securities (Details 4) - USD ($)	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Fair value of marketable securities
Debt securities	$ 1,713,866,000	$ 684,609,000
Equity securities	138,729,000	139,571,000
Total marketable investment securities	1,852,595,000	824,180,000
Corporate bonds
Fair value of marketable securities
Fair value of investments	34,000,000.0		$ 0
Debt securities	1,496,456,000	542,573,000
Other debt securities
Fair value of marketable securities
Debt securities	217,410,000	142,036,000
Level 3
Fair value of marketable securities
Fair value of investments	0	0
Fair value measurements on recurring basis
Fair value of marketable securities
Debt securities	1,713,866,000	684,609,000
Equity securities	138,729,000	139,571,000
Total marketable investment securities	1,852,595,000	824,180,000
Fair value measurements on recurring basis \| Corporate bonds
Fair value of marketable securities
Debt securities	1,496,456,000	542,573,000
Fair value measurements on recurring basis \| Other debt securities
Fair value of marketable securities
Debt securities	217,410,000	142,036,000
Fair value measurements on recurring basis \| Level 1
Fair value of marketable securities
Debt securities	10,436,000	13,311,000
Equity securities	132,291,000	133,736,000
Total marketable investment securities	142,727,000	147,047,000
Fair value measurements on recurring basis \| Level 1 \| Corporate bonds
Fair value of marketable securities
Debt securities	0	0
Fair value measurements on recurring basis \| Level 1 \| Other debt securities
Fair value of marketable securities
Debt securities	10,436,000	13,311,000
Fair value measurements on recurring basis \| Level 2
Fair value of marketable securities
Debt securities	1,703,430,000	671,298,000
Equity securities	6,438,000	5,835,000
Total marketable investment securities	1,709,868,000	677,133,000
Fair value measurements on recurring basis \| Level 2 \| Corporate bonds
Fair value of marketable securities
Debt securities	1,496,456,000	542,573,000
Fair value measurements on recurring basis \| Level 2 \| Other debt securities
Fair value of marketable securities
Debt securities	$ 206,974,000	$ 128,725,000