Investment Securities - Summary of Net Investment Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended	9 Months Ended	3 Months Ended
	Sep. 30, 2013 Successor [Member]	Sep. 30, 2012 Successor [Member]	Sep. 30, 2012 Successor [Member]	Sep. 30, 2013 Successor [Member]	Mar. 19, 2012 Predecessor [Member]
Investment income:
Amortization of premium or discount on fixed-maturity securities	$ (631)	$ (507)	$ (1,263)	$ (1,715)	$ (523)
Investment income on fixed-maturity securities	1,621	2,113	5,377	5,258	2,467
Interest income on cash and equivalents	2	58	87	11	3
Realized net gain (loss) from sale of investment	(767)	2,345	2,617	(754)	176
Unrealized (losses) gains on trading securities held at period end	565	(867)	(594)	(4,022)	1,049
Net investment income	$ 790	$ 3,142	$ 6,224	$ (1,222)	$ 3,172