Investments (Tables)

6 Months Ended

Jun. 30, 2018

Investments [Abstract]

Investment Securities Stated at Fair Value

As of June 30, 2018

			Fair Value Measurements at Reporting Date Using
	Total as of		Quoted Prices in Active Markets for Identical Assets		Significant  Other Observable		Significant Unobservable Inputs
Description	June 30, 2018		(Level 1)		(Level 2)		(Level 3)
Cash & Cash Equivalents	$	296,699,141	$	296,699,141	$	—	$	—
Short-Term Investments:
Certificate of Deposit	160,017,640		160,017,640		—		—
Corporate Bonds	3,000,721		—		3,000,721		—
Government Securities	6,691,825		—		6,691,825		—
Other	1,310,620		1,310,620		—		—
Long-Term Investments:
Corporate Bonds	64,396,193		—		64,396,193		—
Government Securities	55,897,881		—		55,897,881		—
Common Stocks	40,000		40,000		—		—
Municipal Bonds	17,771,621		17,771,621		—		—
Total	$	605,825,642	$	475,839,022	$	129,986,620	$	—

As of December 31, 2017

			Fair Value Measurements at Reporting Date Using
	Total as of		Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
Description	December 31, 2017		(Level 1)		(Level 2)		(Level 3)
Cash & Cash Equivalents	$	569,734,496	$	569,734,496	$	—	$	—
Short-Term Investments:
Certificate of Deposit	130,000,000		130,000,000		—		—
Government Securities	9,011,130		—		9,011,130		—
Mutual Funds	393,581		—		393,581		—
Corporate Bonds	12,944,999		—		12,944,999		—
Other	188,344		188,344		—		—
Long-Term Investments:
Corporate Bonds	3,018,720		—		3,018,720		—
Common Stocks	15,703,371		15,703,371		—		—
Mutual Funds	34,681,337		34,681,337		—		—
Preferred Stock	1,178,991		1,178,991		—		—
Total	$	776,854,969	$	751,486,539	$	25,368,430	$	—

Schedule of Amortized Cost, Unrealized Gains And Losses, And Market Value of Investment Securities

The amortized cost, unrealized gains and losses, and market value of investment securities are shown as of June 30, 2018, and December 31, 2017

As of June 30, 2018:

			Unrealized
	Cost		Gains		Losses		Market Value
Short-Term Investments:
Certificate of Deposit	$	160,003,990	$	13,675	$	(25)	$	160,017,640
Government Securities	6,693,257		280		(1,712)		6,691,825
Corporate Bonds	3,011,806		—		(11,085)		3,000,721
Other	1,310,620		—		—		1,310,620
Long-Term Investments:
Corporate Bonds	64,584,256		5,591		(193,654)		64,396,193
Government Securities	55,912,057		22,868		(37,044)		55,897,881
Common Stocks	40,000		—		—		40,000
Municipal Bonds	17,842,453		5,782		(76,614)		17,771,621
Total	$	309,398,439	$	48,196	$	(320,134)	$	309,126,501

As of December 31, 2017: 

			Unrealized
	Cost		Gains		Losses		Market Value
Short-Term Investments:
Certificate of Deposit	$	130,000,000	$	—	$	—	$	130,000,000
Government Securities	9,024,777		—		(13,647)		9,011,130
Mutual Funds	392,482		1,575		(476)		393,581
Corporate Bonds	12,952,229		—		(7,230)		12,944,999
Other	188,344		—		—		188,344
Long-Term Investments:
Corporate Bonds	3,022,994		—		(4,274)		3,018,720
Common Stocks	10,897,219		5,079,815		(273,663)		15,703,371
Mutual Funds	29,306,540		5,440,344		(65,547)		34,681,337
Preferred Stock	1,141,458		40,533		(3,000)		1,178,991
Total	$	196,926,043	$	10,562,267	$	(367,837)	$	207,120,473

Schedule of Unrealized Loss on Investments

Unrealized losses on investments as of June 30, 2018, are as follows: 

	Aggregate Unrealized Losses		Aggregate Fair Value
Less than one year	$	320,134	$	118,370,168
Greater than one year	—		—
Total	$	320,134	$	118,370,168

Unrealized losses on investments as of December 31, 2017, are as follows: 

	Aggregate Unrealized Losses		Aggregate Fair Value
Less than one year	$	263,655	$	31,223,557
Greater than one year	104,182		285,077
Total	$	367,837	$	31,508,634

Investments Classified by Contractual Maturity Date

Fixed income securities as of June 30, 2018 have contractual maturities as follows:

Due within one year	$	169,743,770
Due between one and five years	128,436,685
Due over five years	10,411,957
	$	308,592,412