INTEREST AND DIVIDEND ON INVESTMENTS- Components of interest and dividend income on investments (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Components of interest and dividend income on investments [Abstract]
Interest income on investment securities and money market investments	$ 45,694	$ 63,769	$ 139,031
Dividends on FHLB stock	1,427	1,885	2,894
Interest income excluding unrealized (loss) gain on derivatives (economic hedges)	47,121	65,654	141,925
Unrealized Gain Loss On Derivatives	0	0	(1,136)
Total interest and dividends on investments	$ 47,121	$ 65,654	$ 140,789