SECURITIES (Amortized Cost, Gross Unrealized Gains and Losses, and Estimated Fair Values of Investment Securities) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amortized Cost	$ 1,072,887	$ 675,474
Gross Unrealized Gains	26,085	11,701
Gross Unrealized (Losses)	(4,195)	(9,827)
Total securities available for sale, Estimated Fair Value	1,094,777	677,348
US Government Agencies Debt Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amortized Cost	1,466	1,654
Gross Unrealized Gains	1,649	499
Gross Unrealized (Losses)
Total securities available for sale, Estimated Fair Value	3,115	2,153
Obligations of States and Political Subdivisions [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amortized Cost	420,297	255,335
Gross Unrealized Gains	14,960	6,107
Gross Unrealized (Losses)	(2,360)	(6,612)
Total securities available for sale, Estimated Fair Value	432,897	254,830
Corporate and Other Bonds [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amortized Cost	79,379	9,479
Gross Unrealized Gains	335	115
Gross Unrealized (Losses)	(476)	(160)
Total securities available for sale, Estimated Fair Value	79,238	9,434
Mortgage Backed Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amortized Cost	558,424	405,389
Gross Unrealized Gains	9,108	4,954
Gross Unrealized (Losses)	(1,331)	(2,981)
Total securities available for sale, Estimated Fair Value	566,201	407,362
Other Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amortized Cost	13,321	3,617
Gross Unrealized Gains	33	26
Gross Unrealized (Losses)	(28)	(74)
Total securities available for sale, Estimated Fair Value	$ 13,326	$ 3,569