Fair Value of Financial Instruments (Tables)

9 Months Ended

Sep. 30, 2019

Fair Value Disclosures [Abstract]

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

Cash and cash equivalents consist of the following:

	September 30, 2019				December 31, 2018
	Cost		Fair Value		Cost		Fair Value
Cash and Cash Equivalents:
Cash and overnight deposits	$	398,235	$	398,235	$	427,307	$	427,307
Corporate commercial paper		788,060		788,708		467,300		467,760
Time deposits		29,675		29,675		29,128		29,128
Total cash and cash equivalents	$	1,215,970	$	1,216,618	$	923,735	$	924,195