SECURITIES (Schedule of Amortized Cost and Estimated Fair Values of Debt Securities by Contractual Maturity) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Available-for-sale, Amortized Cost
Due in one year or less	$ 2,535
Due after one year through five years	89,461
Due after five years through ten years	96,423
Due after ten years	557,915
Amortized cost, total	746,334
Available-for-sale, Fair Value
Due in one year or less	2,588
Due after one year through five years	90,309
Due after five years through ten years	98,530
Due after ten years	560,737
Fair value, total	752,164
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis [Abstract]
Due in one year or less	0
Due after one year through five years	1,118
Due after five years through ten years	2,299
Due after ten years	37,593
Held-to-maturity securities, at amortized cost	41,010	20,179
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Fair Value [Abstract]
Due in one year or less	0
Due after one year through five years	1,159
Due after five years through ten years	2,316
Due after ten years	38,024
Held-to-maturity Securities, Fair Value	$ 41,499	$ 20,425