Fair Value - Presentation of Fair-Value Measurements for Each Major Category of Assets Measured on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	$ 129,234	$ 125,085
Other investments	10,696	10,530
Cash and cash equivalents	110,312	102,429
Total	250,242	238,044
Fixed Maturities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	117,125	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	13,391	8,290
Fixed Maturities | State
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	719	725
Fixed Maturities | Political subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	504	506
Fixed Maturities | Revenue and assessment
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	16,116	16,360
Fixed Maturities | Corporate bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	74,787	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	4,761	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	4,063	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	2,784	3,078
Preferred stock, available-for-sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	1,783	1,767
Mutual funds, available-for-sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, available-for-sale	10,326	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	25,500	20,353
Other investments	0	0
Cash and cash equivalents	110,312	102,429
Total	135,812	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	13,391	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	13,391	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	1,783	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	10,326	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	103,734	104,732
Other investments	0	0
Cash and cash equivalents	0	0
Total	103,734	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	103,734	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	719	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	504	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	16,116	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	74,787	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	4,761	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	4,063	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	2,784	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	10,696	10,530
Cash and cash equivalents	0	0
Total	10,696	10,530
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
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
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
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