Investments - Scheduled Maturities of Company's Fixed Maturity Securities Based on their Fair Values (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Investments Debt And Equity Securities [Abstract]
Securities with Unrealized Gains, One year or less	$ 14,227	$ 14,305
Securities with Unrealized Gains, After one through five years	27,367	25,667
Securities with Unrealized Gains, After five through ten years	22,047	20,445
Securities with Unrealized Gains, After ten years	8,390	3,667
Securities with Unrealized Gains, No single maturity date	17,081	17,506
Securities with Unrealized Gains, Total	89,112	81,590
Securities with Unrealized Losses, One year or less
Securities with Unrealized Losses, After one through five years	10,980	10,888
Securities with Unrealized Losses, After five through ten years	20,553	22,836
Securities with Unrealized Losses, After ten years	1,653	4,008
Securities with Unrealized Losses, No single maturity date		189
Securities with Unrealized Losses, Total	33,186	37,921
Securities with No Unrealized Gains or Losses, One year or less
Securities with No Unrealized Gains or Losses, After one through five years
Securities with No Unrealized Gains or Losses, After five through ten years
Securities with No Unrealized Gains or Losses, After ten years
Securities with No Unrealized Gains or Losses, No single maturity date
Securities with No Unrealized Gains or Losses, Total
All Fixed Maturity Securities, One year or less	14,227	14,305
All Fixed Maturity Securities, After one through five years	38,347	36,555
All Fixed Maturity Securities, After five through ten years	42,600	43,281
All Fixed Maturity Securities, After ten years	10,043	7,675
All Fixed Maturity Securities, No single maturity date	17,081	17,695
All Fixed Maturity Securities, Total	$ 122,298	$ 119,511