Securities - Summary of Cumulative Credit-Related OTTI Charges (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Beginning balance	$ 17,367	$ 18,398
Loss where impairment was not previously recognized	27	212
Additional loss where impairment was previously recognized
Reduction due to credit impaired securities sold	(212)	(1,243)
Ending balance	17,182	17,367
Collateralized Debt Obligations [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Beginning balance	17,155	18,369
Loss where impairment was not previously recognized
Additional loss where impairment was previously recognized
Reduction due to credit impaired securities sold		(1,214)
Ending balance	17,155	17,155
Residential Non-Agency Collateralized Mortgage Obligations [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Beginning balance	212	29
Loss where impairment was not previously recognized		212
Additional loss where impairment was previously recognized
Reduction due to credit impaired securities sold	(212)	(29)
Ending balance		212
Equity securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Beginning balance
Loss where impairment was not previously recognized	27
Additional loss where impairment was previously recognized
Reduction due to credit impaired securities sold
Ending balance	$ 27