INVESTMENT SECURITIES - Roll-Forward of Credit Losses on Debt Securities Held by Corporation (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Other Than Temporary Impairment Credit Losses Recognized In Earnings [Line Items]
Beginning balance of credit losses on debt securities held for which a portion of an OTTI was recognized in OCI	$ 5,777	$ 5,389
Additions:
Credit losses on debt securities for which an OTTI was previously recognized	156	0
Ending balance of credit losses on debt securities held for which a portion of an OTTI was recognized in OCI	$ 5,933	$ 5,389