Adoption of New Accounting Standards (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Recognized a discrete tax benefit	$ 1,800,000	$ 1,800,000
Reclassified tax benefits to operating activities	81,520,530	75,541,699
Cash flows from operating activities	$ 131,191,171	151,868,528
Accounting Standards Update 2016-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassified tax benefits to operating activities		400,000
Cash flows from operating activities		400,000
Accounting Standards Update 2016-09 [Member] | Additional Paid-in Capital [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Tax benefit recognized as additional paid-in capital		(400,000)
Tax benefit recognized as additional paid-in capital, gross		100,000
Tax benefit recognized as additional paid-in capital, tax		$ 500,000