AFFORDABLE HOUSING PARTNERSHIPS AND OTHER TAX CREDIT INVESTMENTS (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
AFFORDABLE HOUSING PARTNERSHIPS AND OTHER TAX CREDIT INVESTMENTS
Minimum compliance period to fully utilize the tax credits			15 years
Investments in affordable housing partnerships	$ 179,606,000		$ 179,606,000		$ 164,776,000
CRA and other tax credit investments	100,900,000		100,900,000		70,200,000
Total unfunded commitments for investments	112,700,000		112,700,000		73,100,000
Increase in amortization of investments in affordable housing partnerships and other tax credit investments	32,200,000		41,800,000
Amortization of investments in affordable housing partnerships and other tax credit investments	36,936,000	4,693,000	55,751,000	14,040,000
Income tax expense (benefit)	$ (13,644,000)	$ 35,749,000	$ 52,923,000	$ 108,023,000
Effective income tax rate (as a percent)	18.20%	32.80%	17.50%	33.00%