Fair Value of Financial Instruments - Included in Notes Payable are the FHLB loan and Subordinated Debentures (Detail) - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Federal Home Loan Bank Advances [Member]
Debt Instrument [Line Items]
Interest rate (percent)	1.73%	1.73%
FHLB loan due and issued with fixed interest, Senior notes due and issued with fixed interest and Affiliate subordinated debentures due with variable interest	$ 21,500,000
Federal Home Loan Bank of Cincinnati [Member]
Debt Instrument [Line Items]
Interest rate (percent)	5.03%	5.03%
FHLB loan due and issued with fixed interest, Senior notes due and issued with fixed interest and Affiliate subordinated debentures due with variable interest	$ 85,000,000
Affiliate Subordinated Debentures Due 2033 [Member]
Debt Instrument [Line Items]
Interest rate (percent)	5.52%	5.13%
FHLB loan due and issued with fixed interest, Senior notes due and issued with fixed interest and Affiliate subordinated debentures due with variable interest	$ 15,500,000.0
Reported Value Measurement [Member]
Debt Instrument [Line Items]
Total notes payable	122,100,000	$ 122,100,000
Reported Value Measurement [Member] | Federal Home Loan Bank Advances [Member]
Debt Instrument [Line Items]
Total notes payable	21,500,000	21,500,000
Reported Value Measurement [Member] | Federal Home Loan Bank of Cincinnati [Member]
Debt Instrument [Line Items]
Total notes payable	85,400,000	85,400,000
Reported Value Measurement [Member] | Affiliate Subordinated Debentures Due 2033 [Member]
Debt Instrument [Line Items]
Total notes payable	15,200,000	15,200,000
Estimate of Fair Value Measurement [Member]
Debt Instrument [Line Items]
Total notes payable	122,200,000	121,800,000
Estimate of Fair Value Measurement [Member] | Federal Home Loan Bank Advances [Member]
Debt Instrument [Line Items]
Total notes payable	21,100,000	21,000,000.0
Estimate of Fair Value Measurement [Member] | Federal Home Loan Bank of Cincinnati [Member]
Debt Instrument [Line Items]
Total notes payable	85,900,000	85,600,000
Estimate of Fair Value Measurement [Member] | Affiliate Subordinated Debentures Due 2033 [Member]
Debt Instrument [Line Items]
Total notes payable	$ 15,200,000	$ 15,200,000