Fair Value of Financial Instruments - Included in Notes Payable are the FHLB loan and Subordinated Debentures (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Carrying Value [Member]
Debt Instrument [Line Items]
Total notes payable	$ 100,800,000	$ 100,800,000
Fair Value [Member]
Debt Instrument [Line Items]
Total notes payable	102,000,000	101,900,000
Federal Home Loan Bank Advances [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
Federal Home Loan Bank Advances [Member] | Carrying Value [Member]
Debt Instrument [Line Items]
Total notes payable	85,300,000	85,300,000
Federal Home Loan Bank Advances [Member] | Fair Value [Member]
Debt Instrument [Line Items]
Total notes payable	86,500,000	86,400,000
Affiliate Subordinated Debentures Due 2033 [Member]
Debt Instrument [Line Items]
Interest rate (percent)	4.46%	4.44%
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
Affiliate Subordinated Debentures Due 2033 [Member] | Carrying Value [Member]
Debt Instrument [Line Items]
Total notes payable	15,500,000	15,500,000
Affiliate Subordinated Debentures Due 2033 [Member] | Fair Value [Member]
Debt Instrument [Line Items]
Total notes payable	$ 15,500,000	$ 15,500,000