INCOME TAXES (Schedule of Income Tax Expense, Difference in Income Tax Rate to Pretax Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Computed expected tax expense	$ 37,208	$ 36,489	$ 31,636
Tax-exempt interest income, net	(6,112)	(6,087)	(5,865)
Valuation allowance adjustment	(2,982)	0	0
Impact of the Tax Act	6,250	0	0
Other, net	(977)	(3,624)	(2,462)
Income tax expense	$ 33,387	$ 26,778	$ 23,309