Credit Facilities - Loan Facilities and Subordinated Debt (Details) - USD ($)	6 Months Ended
	Mar. 31, 2018	Sep. 30, 2017
London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Interest rate (percent)	1.66%
Term Loans | Term Loan with Fifth Third Bank
Line of Credit Facility [Line Items]
Maximum availability	$ 25,000,000.0
Number of equal installment payments	59 months
Periodic principal payment	$ 312,500
Line of Credit
Line of Credit Facility [Line Items]
Maximum availability	10,000,000
Notes Payable to Banks [Member]
Line of Credit Facility [Line Items]
Loan balance	14,896,000	$ 19,688,000
Notes Payable to Banks [Member] | Term Loans
Line of Credit Facility [Line Items]
Maximum availability	25,000,000
Loan balance	$ 14,900,000
Notes Payable to Banks [Member] | Term Loans | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Basis spread on loan	1.66%
Notes Payable to Banks [Member] | Line of Credit
Line of Credit Facility [Line Items]
Maximum availability	$ 10,000,000.0
Loan balance	$ 0
Notes Payable to Banks [Member] | Line of Credit | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Basis spread on loan	1.66%