Securities Available for Sale at Fair Value - Summary of Range of Losses (Details)	6 Months Ended
	Mar. 31, 2018 USD ($) Security
Number of Individual Securities | Security	12
Fair Value	$ 125,062,452
Unrealized Losses	$ (35,354,549)
Securities One [Member]
Number of Individual Securities | Security	3
Fair Value	$ 4,096,452
Unrealized Losses	$ (149,520)
Range of Loss	1%-5%
Securities Two [Member]
Number of Individual Securities | Security	3
Fair Value	$ 35,565,000
Unrealized Losses	$ (3,711,739)
Range of Loss	6%-10%
Securities Three [Member]
Number of Individual Securities | Security	3
Fair Value	$ 47,527,000
Unrealized Losses	$ (8,368,816)
Range of Loss	11%-20%
Securities Four [Member]
Number of Individual Securities | Security	3
Fair Value	$ 37,874,000
Unrealized Losses	$ (23,124,474)
Range of Loss	21%-50%