INCOME TAXES (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Computed statutory federal income tax provision									$ 23,359	$ 20,055	$ 21,904
State taxes, net of federal tax benefit									3,455	2,553	3,101
Nontaxable interest, net									(557)	(542)	(661)
Tax credits									(9,194)	(6,567)	(6,238)
Increase in cash surrender value of life insurance and tax exempt gain on benefit payments									(1,209)	(1,612)	(1,109)
Merger and other related costs (non-deductible)									366	404	0
Other, net									264	382	151
Total expense	$ 2,786	$ 5,299	$ 4,285	$ 4,114	$ 3,127	$ 3,687	$ 3,238	$ 4,621	$ 16,484	$ 14,673	$ 17,148
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									5.17%	4.46%	4.95%
Nontaxable interest, net									(0.83%)	(0.95%)	(1.06%)
Tax credits									(13.77%)	(11.46%)	(9.97%)
Increase in cash surrender value of life insurance and tax exempt gain on benefit payments									(1.81%)	(2.81%)	(1.77%)
Merger and other related costs (non-deductible)									0.55%	0.71%	0.00%
Other, net									0.39%	0.66%	0.25%
Total expense									24.70%	25.61%	27.40%