INVESTMENTS IN DEBT AND EQUITY SECURITIES - Schedule of Continuous Unrealized Loss Positions (Details 3) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 510,717	$ 145,467
Available-for-sale Securities, Continuous Unrealized Loss Position Less Than 12 Months Aggregate Losses	(15,974)	(587)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	31,305	17,945
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer Aggregate Losses	(319)	(677)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	542,022	163,412
Available-for-sale Securities, Continuous Unrealized Loss Position Aggregate Losses	(16,293)	(1,264)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	682,416	67,144
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	(16,502)	(991)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	7,622	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	(11)	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	690,038	67,144
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses	(16,513)	(991)
U.S. Government sponsored agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	45,008	20,018
Available-for-sale Securities, Continuous Unrealized Loss Position Less Than 12 Months Aggregate Losses	(960)	(146)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	19,939	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer Aggregate Losses	(208)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	64,947	20,018
Available-for-sale Securities, Continuous Unrealized Loss Position Aggregate Losses	(1,168)	(146)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	18,501
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	(164)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	18,501
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses	(164)
Residential mortgage-backed [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	401,599	125,449
Available-for-sale Securities, Continuous Unrealized Loss Position Less Than 12 Months Aggregate Losses	(14,043)	(441)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	6,373	270
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer Aggregate Losses	(104)	(56)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	407,972	125,719
Available-for-sale Securities, Continuous Unrealized Loss Position Aggregate Losses	(14,147)	(497)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	662,903	66,011
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	(16,284)	(614)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	7,622	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	(11)	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	670,525	66,011
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses	(16,295)	(614)
State and political subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	27,860
Available-for-sale Securities, Continuous Unrealized Loss Position Less Than 12 Months Aggregate Losses	(588)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer Aggregate Losses	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	27,860
Available-for-sale Securities, Continuous Unrealized Loss Position Aggregate Losses	(588)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	1,012	1,133
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	(54)	(377)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	0	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	1,012	1,133
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses	(54)	(377)
Corporate notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	34,794	0
Available-for-sale Securities, Continuous Unrealized Loss Position Less Than 12 Months Aggregate Losses	(339)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	4,993	17,675
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer Aggregate Losses	(7)	(621)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	39,787	17,675
Available-for-sale Securities, Continuous Unrealized Loss Position Aggregate Losses	(346)	(621)
Equity investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	1,456
Available-for-sale Securities, Continuous Unrealized Loss Position Less Than 12 Months Aggregate Losses	(44)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer Aggregate Losses	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,456
Available-for-sale Securities, Continuous Unrealized Loss Position Aggregate Losses	$ (44)