Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2014

Fair Value Disclosures [Abstract]

Schedule of assets measured at fair value on a recurring basis

The Company’s assets that are measured at fair value on a recurring basis, at September 30, 2014 and December 31, 2013, consist of the following:

			Fair Value Measurements at Reporting Date Using
At September 30, 2014	Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)
Available-for-sale marketable securities:
Unrestricted
U.S. government and government agency obligations	$	51,129	—		$	51,129
Corporate bonds	695,592		—		695,592
Municipal bonds	42,842		—		42,842
Equity securities	5,099		$	5,099	—
	794,662		5,099		789,563
Restricted
Equity securities	54,431		—		54,431
	$	849,093	$	5,099	$	843,994
At December 31, 2013
Available-for-sale marketable securities:
Unrestricted
U.S. government and government agency obligations	$	107,521	—		$	107,521
Corporate bonds	369,193		—		369,193
Commercial paper	23,944		—		23,944
Municipal bonds	36,921		—		36,921
International government agency obligations	2,008		—		2,008
Certificates of deposit	7,514		—		7,514
Equity securities	1,166		$	1,166	—
	$	548,267	$	1,166	$	547,101