Insurance Activity - Schedule of Premiums Assumed and Earned (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended	9 Months Ended	3 Months Ended	12 Months Ended
	Sep. 30, 2012 Successor [Member]	Dec. 31, 2012 Successor [Member]	Mar. 19, 2012 Predecessor [Member]	Dec. 31, 2011 Predecessor [Member]	Dec. 31, 2010 Predecessor [Member]
Premiums assumed	$ 14,210		$ 6,130	$ 34,562	$ 45,271
Change in unearned premiums	184	184	47	222	324
Premiums earned	$ 14,394	$ 14,394	$ 6,177	$ 34,784	$ 45,595