Fair Value of Financial Instruments (Tables)

9 Months Ended

Sep. 30, 2014

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, 2014			December 31, 2013
	Cost		Fair Value	Cost	Fair Value
Cash and Cash Equivalents:
Cash and overnight deposits	$	616,092	616,092	590,317	590,317
Corporate commercial paper	336,405		336,455	629,923	629,990
Time deposits	37,983		37,983	27,412	27,412
Total cash and cash equivalents	990,480		990,530	1,247,652	1,247,719
Short-Term Investments:
Corporate commercial paper	40,296		40,317	26,296	26,321
Time deposits	21		21	41	41
Total short-term investments	40,317		40,338	26,337	26,362
Total	$	1,030,797	1,030,868	1,273,989	1,274,081