Investments (Tables)

6 Months Ended

Jun. 30, 2020

Investments [Abstract]

Investment Securities Stated at Fair Value

Assets or liabilities that have recurring fair value measurements are shown below as of June 30, 2020 and December 31, 2019:

As of June 30, 2020:

			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	June 30, 2020		(Level 1)		(Level 2)		(Level 3)
Cash & Cash Equivalents	$	343,811,484	$	343,811,484	$	—	$	—
Short-Term Investments:
Certificate of Deposit	1,023,558		1,023,558		—		—
Corporate Bonds	18,465,053		—		18,465,053		—
Government Securities	43,412,712		—		43,412,712		—
Municipal Bonds	4,292,331		—		4,292,331		—
Other	2,821,510		2,821,510		—		—
Long-Term Investments:
Asset Backed Securities	42,140,999		—		42,140,999		—
Certificate of Deposit	4,173,150		4,173,150		—		—
Corporate Bonds	21,101,912		—		21,101,912		—
Government Securities	617,226		—		617,226		—
Municipal Bonds	94,430,839		—		94,430,839		—
Total	$	576,290,774	$	351,829,702	$	224,461,072	$	—

As of December 31, 2019:

			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, 2019		(Level 1)		(Level 2)		(Level 3)
Cash & Cash Equivalents	$	296,321,622	$	296,321,622	$	—	$	—
Short-Term Investments:
Certificate of Deposit	50,099,795		50,099,795		—		—
Corporate Bonds	29,219,685		—		29,219,685		—
Government Securities	58,432,823		—		58,432,823		—
Other	2,631,750		2,631,750		—		—
Long-Term Investments:
Asset-backed Securities	25,791,029		—		25,791,029		—
Certificate of Deposit	3,557,798		3,557,798				—
Corporate Bonds	22,815,998		—		22,815,998		—
Governmental Securities	6,088,190		—		6,088,190		—
Municipal Bonds	72,638,690		—		72,638,690		—
Total	$	567,597,380	$	352,610,965	$	214,986,415	$	—

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, 2020 and December 31, 2019:

As of June 30, 2020:

			Unrealized
	Cost		Gains		Losses		Market Value
Short-Term Investments:
Certificate of Deposit	$	1,000,000	$	23,558	$	—	$	1,023,558
Corporate Bonds	18,328,367		138,975		(2,289)		18,465,053
Government Securities	43,146,665		266,047		—		43,412,712
Municipal Bonds	4,256,184		36,147		—		4,292,331
Other	2,821,510		—		—		2,821,510
Long-Term Investments:
Asset Backed Securities	41,140,592		1,032,218		(31,811)		42,140,999
Certificate of Deposit	4,006,912		166,238		—		4,173,150
Corporate Bonds	20,230,114		871,798		—		21,101,912
Government Securities	614,995		2,231		—		617,226
Municipal Bonds	89,744,967		4,707,257		(21,385)		94,430,839
Total	$	225,290,306	$	7,244,469	$	(55,485)	$	232,479,290

As of December 31, 2019: 

			Unrealized
	Cost		Gains		Losses		Market Value
Short-Term Investments:
Certificate of Deposit	$	50,099,795	$	—	$	—	$	50,099,795
Corporate Bonds	29,025,624		194,061		—		29,219,685
Government Securities	58,343,911		99,917		(11,005)		58,432,823
Other	2,631,750		—		—		2,631,750
Long-Term Investments:
Asset-backed Securities	25,971,156		—		(180,127)		25,791,029
Certificate of Deposit	3,500,000		58,808		(1,010)		3,557,798
Corporate Bonds	22,306,130		509,868		—		22,815,998
Government Securities	6,012,705		75,485		—		6,088,190
Municipal Bonds	71,997,996		1,036,116		(395,422)		72,638,690
Total	$	269,889,067	$	1,974,255	$	(587,564)	$	271,275,758

Schedule of Unrealized Loss on Investments

Unrealized losses on investments as of June 30, 2020, are as follows:

	Aggregate Unrealized Losses		Aggregate Fair Value
Loss duration of less than one year	$	55,485	$	18,860,975
Loss duration of greater than one year	—		—
Total	$	55,485	$	18,860,975

Unrealized losses on investments as of December 31, 2019, are as follows: 

	Aggregate Unrealized Losses		Aggregate Fair Value
Loss duration of less than one year	$	587,564	$	90,721,081
Loss duration of greater than one year	—		—
Total	$	587,564	$	90,721,081

Investments Classified by Contractual Maturity Date

Fixed income securities as of June 30, 2020 have contractual maturities as follows:

Due within one year	$	67,193,654
Due between one and five years	46,324,201
Due over five years	116,139,925
	$	229,657,780