Investments - Summary of Fixed Maturities and Equity Securities with Unrealized Losses (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	$ 23,576	$ 207,175
Less Than 12 Months, Unrealized Losses	116	1,898
More Than 12 Months, Fair Value	14,919	43,913
More Than 12 Months, Unrealized Losses	123	488
U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	2,663	50,803
Less Than 12 Months, Unrealized Losses	13	822
More Than 12 Months, Fair Value	264	4,642
More Than 12 Months, Unrealized Losses	1	104
Obligations of States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value		65,171
Less Than 12 Months, Unrealized Losses		363
More Than 12 Months, Fair Value	1,572	13,405
More Than 12 Months, Unrealized Losses	12	99
Corporate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	6,919	16,694
Less Than 12 Months, Unrealized Losses	27	84
More Than 12 Months, Fair Value		6,852
More Than 12 Months, Unrealized Losses		72
Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	9,966	72,878
Less Than 12 Months, Unrealized Losses	50	536
More Than 12 Months, Fair Value	13,083	19,014
More Than 12 Months, Unrealized Losses	110	213
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	4,028	1,629
Less Than 12 Months, Unrealized Losses	$ 26	$ 93