Fair Value of Financial Instruments - Included in Notes Payable are Senior Notes and Subordinated Debentures (Detail) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Interest rate (percent)	5.28%	5.28%
Federal Home Loan Bank Advances
Debt Instrument [Line Items]
Interest rate (percent)	1.73%	5.03%
Debt instrument, issued	$ 21,500,000.0
Federal Home Loan Bank of Cincinnati [Member]
Debt Instrument [Line Items]
Interest rate (percent)	5.03%
Debt instrument, issued	$ 85,000,000
Affiliate Subordinated Debentures due 2033
Debt Instrument [Line Items]
Interest rate (percent)	5.13%	4.61%
Debt instrument, issued	$ 15,500,000
Carrying value
Debt Instrument [Line Items]
Total notes payable	122,100,000	$ 100,500,000
Carrying value | Federal Home Loan Bank Advances
Debt Instrument [Line Items]
Total notes payable	21,500,000	85,300,000
Carrying value | Federal Home Loan Bank of Cincinnati [Member]
Debt Instrument [Line Items]
Total notes payable	85,400,000
Carrying value | Affiliate Subordinated Debentures due 2033
Debt Instrument [Line Items]
Total notes payable	15,200,000	15,200,000
Fair value
Debt Instrument [Line Items]
Total notes payable	121,800,000	100,700,000
Fair value | Federal Home Loan Bank Advances
Debt Instrument [Line Items]
Total notes payable	21,000,000.0	85,500,000
Fair value | Federal Home Loan Bank of Cincinnati [Member]
Debt Instrument [Line Items]
Total notes payable	85,600,000
Fair value | Affiliate Subordinated Debentures due 2033
Debt Instrument [Line Items]
Total notes payable	$ 15,200,000	$ 15,200,000