Fair Value - Presentation of Fair-Value Measurements for Each Major Category of Assets Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	$ 135,745	$ 125,085
Other investments	12,087	10,530
Cash and cash equivalents	107,207	102,429
Total	255,039	238,044
Fixed Maturities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	122,301	113,022
Fixed Maturities | U.S. government and agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	13,314	8,290
Fixed Maturities | State
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	703	725
Fixed Maturities | Political subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	499	506
Fixed Maturities | Revenue and assessment
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	13,480	16,360
Fixed Maturities | Corporate bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	86,189	75,119
Fixed Maturities | Collateralized mortgage obligations: Agency Backed
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	1,827	4,807
Fixed Maturities | Collateralized mortgage obligations: Non-agency backed - residential
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	3,670	4,137
Fixed Maturities | Collateralized mortgage obligations: Non-agency backed - commercial
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	2,619	3,078
Preferred stock, available-for-sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	1,727	1,767
Mutual funds, available-for-sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	11,717	10,296
Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	26,758	20,353
Other investments	0	0
Cash and cash equivalents	107,207	102,429
Total	133,965	122,782
Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed Maturities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	13,314	8,290
Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed Maturities | U.S. government and agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	13,314	8,290
Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed Maturities | State
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed Maturities | Political subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed Maturities | Revenue and assessment
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed Maturities | Corporate bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed Maturities | Collateralized mortgage obligations: Agency Backed
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed Maturities | Collateralized mortgage obligations: Non-agency backed - residential
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed Maturities | Collateralized mortgage obligations: Non-agency backed - commercial
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets (Level 1) | Preferred stock, available-for-sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	1,727	1,767
Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets (Level 1) | Mutual funds, available-for-sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	11,717	10,296
Fair Value Measurements Using Significant Other Observable Inputs (Level 2)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	108,987	104,732
Other investments	0	0
Cash and cash equivalents	0	0
Total	108,987	104,732
Fair Value Measurements Using Significant Other Observable Inputs (Level 2) | Fixed Maturities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	108,987	104,732
Fair Value Measurements Using Significant Other Observable Inputs (Level 2) | Fixed Maturities | U.S. government and agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Significant Other Observable Inputs (Level 2) | Fixed Maturities | State
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	703	725
Fair Value Measurements Using Significant Other Observable Inputs (Level 2) | Fixed Maturities | Political subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	499	506
Fair Value Measurements Using Significant Other Observable Inputs (Level 2) | Fixed Maturities | Revenue and assessment
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	13,480	16,360
Fair Value Measurements Using Significant Other Observable Inputs (Level 2) | Fixed Maturities | Corporate bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	86,189	75,119
Fair Value Measurements Using Significant Other Observable Inputs (Level 2) | Fixed Maturities | Collateralized mortgage obligations: Agency Backed
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	1,827	4,807
Fair Value Measurements Using Significant Other Observable Inputs (Level 2) | Fixed Maturities | Collateralized mortgage obligations: Non-agency backed - residential
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	3,670	4,137
Fair Value Measurements Using Significant Other Observable Inputs (Level 2) | Fixed Maturities | Collateralized mortgage obligations: Non-agency backed - commercial
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	2,619	3,078
Fair Value Measurements Using Significant Other Observable Inputs (Level 2) | Preferred stock, available-for-sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Significant Other Observable Inputs (Level 2) | Mutual funds, available-for-sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Other investments	2,692	947
Cash and cash equivalents	0	0
Total	2,692	947
Fair Value Measurements Using Significant Unobservable Inputs (Level 3) | Fixed Maturities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Significant Unobservable Inputs (Level 3) | Fixed Maturities | U.S. government and agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Significant Unobservable Inputs (Level 3) | Fixed Maturities | State
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Significant Unobservable Inputs (Level 3) | Fixed Maturities | Political subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Significant Unobservable Inputs (Level 3) | Fixed Maturities | Revenue and assessment
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Significant Unobservable Inputs (Level 3) | Fixed Maturities | Corporate bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Significant Unobservable Inputs (Level 3) | Fixed Maturities | Collateralized mortgage obligations: Agency Backed
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Significant Unobservable Inputs (Level 3) | Fixed Maturities | Collateralized mortgage obligations: Non-agency backed - residential
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Significant Unobservable Inputs (Level 3) | Fixed Maturities | Collateralized mortgage obligations: Non-agency backed - commercial
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Significant Unobservable Inputs (Level 3) | Preferred stock, available-for-sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Significant Unobservable Inputs (Level 3) | Mutual funds, available-for-sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Proportionate Share of Net Assets (NAV)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Other investments	9,395	9,583
Cash and cash equivalents	0	0
Total	9,395	9,583
Fair Value Measurements Using Proportionate Share of Net Assets (NAV) | Fixed Maturities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Proportionate Share of Net Assets (NAV) | Fixed Maturities | U.S. government and agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Proportionate Share of Net Assets (NAV) | Fixed Maturities | State
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Proportionate Share of Net Assets (NAV) | Fixed Maturities | Political subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Proportionate Share of Net Assets (NAV) | Fixed Maturities | Revenue and assessment
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Proportionate Share of Net Assets (NAV) | Fixed Maturities | Corporate bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Proportionate Share of Net Assets (NAV) | Fixed Maturities | Collateralized mortgage obligations: Agency Backed
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Proportionate Share of Net Assets (NAV) | Fixed Maturities | Collateralized mortgage obligations: Non-agency backed - residential
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Proportionate Share of Net Assets (NAV) | Fixed Maturities | Collateralized mortgage obligations: Non-agency backed - commercial
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Proportionate Share of Net Assets (NAV) | Preferred stock, available-for-sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	0	0
Fair Value Measurements Using Proportionate Share of Net Assets (NAV) | Mutual funds, available-for-sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	$ 0	$ 0