INCOME TAXES (Computation of Differences Between Financial Statement Tax Expense And Amounts) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income taxes at statutory federal rate of 35%									$ 31,372	$ 27,026	$ 24,220
Increase (decrease) in taxes resulting from:
Tax exempt income									(2,015)	(1,498)	(1,323)
Nondeductible expense									193	190	206
State income tax, net of federal tax effect									846	726	951
Captive insurance premium income									(378)	(361)	(363)
Tax credits									(326)	(311)	(241)
Bank owned life insurance									(619)	(554)	(605)
Long - term incentive plan									(854)	0	0
Revaluation deferred tax asset at 21% rate									4,137	0	0
Other									(52)	(85)	(12)
Total income tax expense	$ 11,779	$ 7,573	$ 7,394	$ 5,558	$ 6,582	$ 6,498	$ 6,091	$ 5,962	$ 32,304	$ 25,133	$ 22,833