Investments (Tables)

12 Months Ended

Dec. 31, 2016

Investments Debt And Equity Securities [Abstract]

Schedule of Fair Value of Held-to-maturity Securities Recorded at Amortized Cost

Our investments in held–to–maturity securities consist of the following as of December 31:

	2016		2015
Corporate securities	$	227,854	$	492,955
Commercial paper		292,466		604,986
U.S. Treasury securities		161,778		105,064
Certificates of deposit		—		20,750
Total	$	682,098	$	1,223,755

Schedule of Investments Recorded in Consolidated Balance Sheets

These investments are recorded in our consolidated balance sheets as follows as of December 31:

	2016		2015
Cash and cash equivalents	$	341,680	$	38,420
Short-term investments (1)		340,418		1,185,335
	$	682,098	$	1,223,755

⁽¹⁾ As of December 31, 2016 and 2015, $9.1 million and $299.3 million, respectively, of these investments serve as collateral for certain of our obligations.