INVESTMENTS IN DEBT AND EQUITY SECURITIES (Investments Classified by Contractual Maturity Date) (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Available For Sale Securities, Contractual Maturities, Amortized Cost [Abstract]
Within one year	$ 62,932
After one year through five years	135,179
After five years through ten years	191,741
After ten years	1,096,656
Equity investments, no maturity date	2,000
Available for sale securities, amortized cost	1,488,508	$ 1,433,846
Available For Sale Securities, Contractual Maturities, Fair Value [Abstract]
Within one year	63,546
After one year through five years	136,799
After five years through ten years	193,981
After ten years	1,105,221
Equity securities, no maturity date	1,956
Available-for-sale securities, fair value	1,501,503	1,445,689
Held To Maturity Debt Securities, Contractual Maturities, Amortized Cost [Abstract]
Within one year	565
After one year through five years	101,555
After five years through ten years	56,000
After ten years	429,080
Held to maturity debt securities, amortized cost	587,200	618,148
Held To Maturity Debt Securities, Contractual Maturities, Fair Value [Abstract]
Within one year	565
After one year through five years	102,154
After five years through ten years	54,759
After ten years	426,192
Held to maturity debt securities, fair value	$ 583,670	$ 614,272
Available For Sale Securities Weighted Average Yield [Abstract]
Within one year	2.50%
After one year through five years	1.84%
After five years through ten years	2.77%
After ten years	2.20%
Equity investments, no maturity date	2.18%
Available for sale securities, weighted average yield	2.24%
Held To Maturity Debt Securities Weighted Average Yield [Abstract]
Within one year	3.07%
After one year through five years	1.93%
After five years through ten years	1.18%
After ten years	2.09%
Held to maturity debt securities, weighted average yield	1.97%