7. Restricted Cash and Investments (Tables)

3 Months Ended

Mar. 31, 2017

Restricted Cash and Investments [Abstract]

Restricted cash and investments consisted of the following at March 31, 2017 and December 31, 2016 (in thousands):



	March 31, 2017		December 31, 2016
Restricted cash	$	15,537	$	31,381
Restricted investments	339,700		339,926
Total restricted cash and investments (1)	$	355,237	$	371,307


(1)	There was an additional $38.7 million and $37.2 million of restricted cash included within “Prepaid expenses and other current assets” at March 31, 2017 and December 31, 2016, respectively.

Restricted Available For Sale Securities

The following tables summarize the unrealized gains and losses related to our restricted investments, by major security type, as of March 31, 2017 and December 31, 2016 (in thousands):



	As of March 31, 2017
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Foreign government obligations	$	110,608	$	56,739	$	—	$	167,347
U.S. government obligations	170,597		10,695		8,939		172,353
Total	$	281,205	$	67,434	$	8,939	$	339,700



	As of December 31, 2016
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Foreign government obligations	$	107,604	$	62,350	$	—	$	169,954
U.S. government obligations	169,294		10,468		9,790		169,972
Total	$	276,898	$	72,818	$	9,790	$	339,926