Scheduled Maturity Dates for Fixed Maturity Securities by Number of Years Until Maturity (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Fair Value
Due in one year or less	$ 61,556
Due after one year through five years	751,955
Due after five years through ten years	379,451
Due after ten years	363,144
Mortgage- and asset-backed securities	664,749
Total	2,220,855	2,047,873
Amortized Cost
Due in one year or less	61,457
Due after one year through five years	737,324
Due after five years through ten years	373,226
Due after ten years	356,762
Mortgage- and asset-backed securities	648,325
Total	$ 2,177,094	$ 2,036,999