INVESTMENTS IN DEBT AND EQUITY SECURITIES (Investments Classified by Contractual Maturity Date) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Available For Sale Securities, Contractual Maturities, Amortized Cost [Abstract]
Within one year	$ 7,015
After one year through five years	96,431
After five years through ten years	224,729
After ten years	989,792
Equity investments, no maturity date	2,000
Available for sale securities, amortized cost	1,319,967	$ 1,433,846
Available For Sale Securities, Contractual Maturities, Fair Value [Abstract]
Within one year	7,128
After one year through five years	96,925
After five years through ten years	227,822
After ten years	996,106
Equity investments, no maturity date	1,976
Available for sale securities, fair value	1,329,957	1,445,689
Held To Maturity Debt Securities, Contractual Maturities, Amortized Cost [Abstract]
Within one year	565
After one year through five years	118,363
After five years through ten years	65,039
After ten years	411,210
Held to maturity debt securities, amortized cost	595,177	618,148
Held To Maturity Debt Securities, Contractual Maturities, Fair Value [Abstract]
Within one year	565
After one year through five years	118,548
After five years through ten years	64,515
After ten years	412,187
Held to maturity debt securities, fair value	$ 595,815	$ 614,272
Available For Sale Securities Weighted Average Yield [Abstract]
Within one year	3.81%
After one year through five years	1.93%
After five years through ten years	2.92%
After ten years	2.25%
Equity investments, no maturity date	2.16%
Available for sale securities, weighted average yield	2.32%
Held To Maturity Debt Securities Weighted Average Yield [Abstract]
Within one year	3.07%
After one year through five years	1.80%
After five years through ten years	1.43%
After ten years	1.90%
Held to maturity debt securities, weighted average yield	1.83%