Investments - Summary of Gross Realized Gains and Losses from Investments before Applicable Income Taxes (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Gain (Loss) on Investments [Line Items]
Gross realized gains	$ 426,000	$ 742,000	$ 2,426,000	$ 3,823,000
Gross realized losses	75,000	393,000	129,000	879,000
Net realized gains	351,269	349,164	2,296,909	2,943,710
Fixed Maturities [Member]
Gain (Loss) on Investments [Line Items]
Gross realized gains	19,000	390,000	1,367,000	2,730,000
Gross realized losses	33,000	304,000	34,000	328,000
Equity Securities [Member]
Gain (Loss) on Investments [Line Items]
Gross realized gains	407,000	352,000	1,059,000	1,093,000
Gross realized losses	$ 42,000	$ 89,000	$ 95,000	$ 551,000