Fair Value - Presentation of Fair-Value Measurements for Each Major Category of Assets Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	$ 129,088	$ 131,582
Other investments	10,322	11,256
Cash and cash equivalents	134,439	115,587
Total	273,849	258,425
Fixed Maturities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	115,227	118,442
Fixed Maturities | U.S. government and agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	11,623	13,113
Fixed Maturities | State
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	703	702
Fixed Maturities | Political subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	4,372	4,363
Fixed Maturities | Revenue and assessment
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	11,163	12,644
Fixed Maturities | Corporate bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	81,170	80,785
Fixed Maturities | Collateralized mortgage obligations: Agency Backed
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	857	873
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	3,123	3,455
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	2,216	2,507
Preferred stock, available-for-sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	1,848	1,723
Mutual funds, available-for-sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	12,013	11,417
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	25,484	26,253
Cash and cash equivalents	134,439	115,587
Total	159,923	141,840
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	11,623	13,113
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	11,623	13,113
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	1,848	1,723
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	12,013	11,417
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	103,604	105,329
Total	103,604	105,329
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	103,604	105,329
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	702
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	4,372	4,363
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	11,163	12,644
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	81,170	80,785
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	857	873
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	3,123	3,455
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	2,216	2,507
Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	4,177	3,276
Total	4,177	3,276
Fair Value Measurements Using Proportionate Share of Net Assets (NAV)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	6,145	7,980
Total	$ 6,145	$ 7,980