Investments - Summary of Reclassifications of Fixed Maturities at Fair Value (Detail) (USD $)	Jun. 30, 2014	Dec. 31, 2013	Nov. 30, 2013
Schedule of Equity Method Investments [Line Items]
Transfers from available for sale to held to maturity, Amortized Cost			$ 227,295,293
Transfers from available for sale to held to maturity, Estimated Fair Value	308,752,000	238,790,000	212,228,289
U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies [Member]
Schedule of Equity Method Investments [Line Items]
Transfers from available for sale to held to maturity, Amortized Cost			50,627,225
Transfers from available for sale to held to maturity, Estimated Fair Value	52,956,000	47,076,000	47,914,311
Obligations of States and Political Subdivisions [Member]
Schedule of Equity Method Investments [Line Items]
Transfers from available for sale to held to maturity, Amortized Cost			88,456,842
Transfers from available for sale to held to maturity, Estimated Fair Value	102,736,000	108,454,000	79,866,801
Corporate Securities [Member]
Schedule of Equity Method Investments [Line Items]
Transfers from available for sale to held to maturity, Amortized Cost			15,745,976
Transfers from available for sale to held to maturity, Estimated Fair Value	53,934,000	14,780,000	14,879,294
Mortgage-Backed Securities [Member]
Schedule of Equity Method Investments [Line Items]
Transfers from available for sale to held to maturity, Amortized Cost			72,465,250
Transfers from available for sale to held to maturity, Estimated Fair Value	$ 99,126,000	$ 68,480,000	$ 69,567,883