Fair Value of Financial Instruments (Tables)

9 Months Ended

Sep. 30, 2016

Fair Value Disclosures [Abstract]

Schedule of Fair value of Cash and Cash Equivalents by Balance Sheet Grouping

Cash, cash equivalents and short-term investments consist of the following:

	September 30, 2016			December 31, 2015
	Cost		Fair Value	Cost	Fair Value
Cash and Cash Equivalents:
Cash and overnight deposits	$	451,234	451,234	445,582	445,582
Corporate commercial paper	535,393		535,452	302,433	302,480
Time deposits	56,073		56,073	59,781	59,781
Total cash and cash equivalents	1,042,700		1,042,759	807,796	807,843
Short-Term Investments:
Time deposits	48		48	40	40
Total	$	1,042,748	1,042,807	807,836	807,883