INVESTMENT SECURITIES (Details 3) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013 item	Dec. 31, 2012 item
INVESTMENT SECURITIES
Number of investment securities in an unrealized loss position	281	118
Total temporary impaired securities
Less than 12 months, Fair Value	$ 1,006,524	$ 303,314
Less than 12 months, Unrealized Losses	(39,175)	(2,795)
Total, Fair Value	1,006,524	303,314
Total, Unrealized Losses	(39,175)	(2,795)
States and political subdivisions debt securities
Total temporary impaired securities
Less than 12 months, Fair Value	169,269	73,128
Less than 12 months, Unrealized Losses	(10,799)	(1,194)
Total, Fair Value	169,269	73,128
Total, Unrealized Losses	(10,799)	(1,194)
Corporations debt securities
Total temporary impaired securities
Less than 12 months, Fair Value	87,203	23,205
Less than 12 months, Unrealized Losses	(2,851)	(63)
Total, Fair Value	87,203	23,205
Total, Unrealized Losses	(2,851)	(63)
U.S. Government sponsored entities mortgage-backed securities
Total temporary impaired securities
Less than 12 months, Fair Value	685,319	206,981
Less than 12 months, Unrealized Losses	(20,206)	(1,538)
Total, Fair Value	685,319	206,981
Total, Unrealized Losses	(20,206)	(1,538)
Non-agency collateralized mortgage obligations mortgage-backed securities
Total temporary impaired securities
Less than 12 months, Fair Value	64,733
Less than 12 months, Unrealized Losses	(5,319)
Total, Fair Value	64,733
Total, Unrealized Losses	$ (5,319)