Scheduled Maturity Dates for Fixed Maturity Securities by Number of Years Until Maturity (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Fair Value
Due in one year or less	$ 78,570
Due after one year through five years	739,594
Due after five years through ten years	407,558
Due after ten years	277,762
Mortgage- and asset-backed securities	659,229
Total	2,162,713	2,047,873
Amortized Cost
Due in one year or less	77,743
Due after one year through five years	725,355
Due after five years through ten years	406,355
Due after ten years	277,500
Mortgage- and asset-backed securities	646,539
Total	$ 2,133,492	$ 2,036,999