SECURITIES (Schedule of Unrealized Gross Losses and Estimated Fair values of Investment Securities) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Fair Value - Less Than 12 Months	$ 457,590	$ 115,880
Unrealized Losses - Less Than 12 Months	(16,377)	(199)
Fair Value - 12 Months of More	5,370	8,174
Unrealized Losses - 12 Months or More	(240)	(697)
Fair Value	462,960	124,054
Unrealized losses	(16,617)	(896)
Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Fair Value - Less Than 12 Months	149,819	42,782
Unrealized Losses - Less Than 12 Months	(4,612)	(79)
Fair Value - 12 Months of More	13
Fair Value	149,832	42,782
Unrealized losses	(4,612)	(79)
Collateralized mortgage obligations
Schedule of Available-for-sale Securities [Line Items]
Fair Value - Less Than 12 Months	307,640	73,098
Unrealized Losses - Less Than 12 Months	(11,763)	(120)
Fair Value	307,640	73,098
Unrealized losses	(11,763)	(120)
Private issue collateralized mortgage obligations
Schedule of Available-for-sale Securities [Line Items]
Fair Value - Less Than 12 Months	131
Unrealized Losses - Less Than 12 Months	(2)
Fair Value - 12 Months of More	5,357	8,174
Unrealized Losses - 12 Months or More	(240)	(697)
Fair Value	5,488	8,174
Unrealized losses	$ (242)	$ (697)