Summary of Significant Accounting Policies - Summary of Effects of Adopting Accounting Standards on Financial Statements (Details) - USD ($)	Sep. 30, 2018	Jan. 31, 2018	Dec. 31, 2017
Summary Of Significant Accounting Policies [Line Items]
Balance at December 31, 2017 As Previously Reported	$ 37,603,687		$ 38,500,984
Balance at January 31, 2018 As Adjusted			38,500,984
Accumulated Other Comprehensive Income
Summary Of Significant Accounting Policies [Line Items]
Balance at December 31, 2017 As Previously Reported			796,603
Adjustment from financial instruments update ASU 2016-01			(796,603)
Accumulated Other Comprehensive Income | ASU 2016-01
Summary Of Significant Accounting Policies [Line Items]
Adjustment from financial instruments update ASU 2016-01		$ (796,603)
Retained Earnings
Summary Of Significant Accounting Policies [Line Items]
Balance at December 31, 2017 As Previously Reported	$ 3,591,588		3,746,323
Adjustment from financial instruments update ASU 2016-01			796,603
Balance at January 31, 2018 As Adjusted		4,542,926	4,542,926
Retained Earnings | ASU 2016-01
Summary Of Significant Accounting Policies [Line Items]
Adjustment from financial instruments update ASU 2016-01		796,603
Investments in securities
Summary Of Significant Accounting Policies [Line Items]
Balance at December 31, 2017 As Previously Reported			$ 1,552,090
Investments in securities | ASU 2016-01
Summary Of Significant Accounting Policies [Line Items]
Adjustment from financial instruments update ASU 2016-01		(1,552,090)
Marketable Equity Securities
Summary Of Significant Accounting Policies [Line Items]
Balance at January 31, 2018 As Adjusted		1,552,090
Marketable Equity Securities | ASU 2016-01
Summary Of Significant Accounting Policies [Line Items]
Adjustment from financial instruments update ASU 2016-01		$ 1,552,090