Other Comprehensive Income (Loss) - Components of Other Comprehensive Income (loss) Pre-tax and After-Tax (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013
Equity [Abstract]
Net unrealized gains (losses) on available for sale investments arising during the periods, Pre-tax	$ 3,507	$ (739)
Less: realized gains (losses) on investments, Pre-tax	56	55
Change in net unrealized gains (losses) on available for sale investments, Pre-tax	3,451	(794)
Other comprehensive income (loss), Pre-tax	3,451	(794)
Net unrealized gains (losses) on available for sale investments arising during the periods	1,353	(285)
Less: realized gains (losses) on investments	22	21
Change in net unrealized gains (losses) on available for sale investments	1,331	(306)
Other comprehensive income (loss)	1,331	(306)
Net unrealized gains (losses) on available for sale investments arising during the periods	2,154	(454)
Less: realized gains (losses) on investments	34	34
Change in net unrealized gains (losses) on available for sale investments	2,120	(488)	[1]
Other comprehensive income (loss)	$ 2,120	$ (488)

[1] Represents change in fair value of AFS investments for the period presented, net of tax benefit of $306 thousand.