FEDERAL HOME LOAN BANK ADVANCES (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Amount of FHLB advances
Year one		$ 246,046,000
Year two		100,000,000
Year three	78,683,000	186,546,000
Year four	52,656,000	53,800,000
Year five	21,557,000	216,616,000
After year five	302,355,000	411,140,000
Total	455,251,000	1,214,148,000
Weighted average interest rates
Year one (as a percent)		0.97%
Year two (as a percent)		1.03%
Year three (as a percent)	4.43%	4.55%
Year four (as a percent)	4.43%	4.43%
Year five (as a percent)	4.46%	4.46%
After year five (as a percent)	4.04%	4.16%
Total (as a percent)	4.17%	3.38%
Overnight borrowings		200,000,000
Available borrowing capacity from unused FHLB advances	3,610,000,000	2,230,000,000
Long-term FHLB advances prepaid	523,500,000	1,120,000,000
Additional prepayment penalties	11,800,000	13,800,000
Additional available borrowing capacity from the Federal Reserve Bank's discount window	$ 1,020,000,000	$ 588,800,000