INCOME TAXES (Details 1) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Computed statutory federal income tax provision									$ 32,262	$ 29,310	$ 23,359
State taxes, net of federal tax benefit									4,500	4,104	3,455
Nontaxable interest, net									(973)	(795)	(557)
New Markets Tax Credits									(6,514)	(6,708)	(9,000)
Low Income Housing Project Investments									(1,182)	(594)	(194)
Increase in cash surrender value of life insurance and tax exempt gain on benefit payments									(1,292)	(1,782)	(1,209)
Merger and other related costs (non-deductible)									185	274	366
Other, net									191	90	264
Total expense	$ 8,268	$ 7,867	$ 7,213	$ 3,869	$ 6,201	$ 6,415	$ 5,934	$ 5,350	$ 27,218	$ 23,899	$ 16,484
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Computed statutory federal income tax provision									35.00%	35.00%	35.00%
State taxes, net of federal tax benefit									4.88%	4.90%	5.17%
Nontaxable interest, net									(1.06%)	(0.95%)	(0.83%)
New Markets Tax Credits									(7.07%)	(8.01%)	(13.48%)
Low Income Housing Project Investments									(1.28%)	(0.71%)	(0.29%)
Increase in cash surrender value of life insurance and tax exempt gain on benefit payments									(1.40%)	(2.13%)	(1.81%)
Merger and other related costs (non-deductible)									0.20%	0.33%	0.55%
Other, net									0.22%	0.11%	0.39%
Total expense									29.53%	28.54%	24.70%
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount									$ 41	$ 0	$ 0
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent									0.04%	0.00%	0.00%