Investments - Amortized Cost and Fair Value of Fixed Maturities Available for Sale by Contractual Maturity (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013
Schedule of Available-for-sale Securities [Line Items]
Fixed Maturities Securities Available for Sale, Due in one year or less, Amortized cost	$ 5,903
Fixed Maturities Securities Available for Sale, Due after one year through five years, Amortized cost	189,607
Fixed Maturities Securities Available for Sale, Due after five years through ten years, Amortized cost	5,162
Fixed Maturities Securities Available for Sale, Due after ten years, Amortized cost
Fixed Maturities Securities Available for Sale, Amortized cost, Total	292,216
Fixed Maturities Securities Available for Sale, Due in one year or less, Fair Value	5,893
Fixed Maturities Securities Available for Sale, Due after one year through five years, Fair Value	187,391
Fixed Maturities Securities Available for Sale, Due after five years through ten years, Fair Value	4,841
Fixed Maturities Securities Available for Sale, Due after ten years, Fair Value
Fixed Maturities Securities Available for Sale, Fair Value, Total	289,388
Mortgage-Backed and Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed Maturities Securities Available for Sale, Mortgage-backed Securities, Amortized cost	91,544
Fixed Maturities Securities Available for Sale, Fair Value, Total	$ 91,263