Mortgage-Backed Securities - By Type (Details) - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Schedule of Trading Securities and Other Trading Assets [Line Items]
Fair Value	$ 142,482,975	$ 130,301,989
Total Pass Through Certificates [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Fair Value	139,010,000	124,299,000
Total Strucutured Certificates [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Fair Value	3,473,000	6,003,000
Fixed-rate Mortgages [Member] | Total Pass Through Certificates [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Fair Value	139,010,000	124,299,000
Interest Only Securities [Member] | Total Strucutured Certificates [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Fair Value	2,061,000	2,654,000
Inverse Interest Only Securities [Member] | Total Strucutured Certificates [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Fair Value	$ 1,412,000	$ 3,349,000