ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Net Accumulated Other Comprehensive Income (Loss)) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ (15,754)	$ (6,857)
Other comprehensive income before reclassification, net of tax	6,508	(9,368)
Reclassifications from accumulated other comprehensive income, net of tax	(196)	84
Current period change in other comprehensive income, net of tax	6,704	(9,284)
Reclassfication of tax effects from accumulated other comprehensive income		(1,477)
Ending Balance	(9,050)	(17,618)
Unrealized Gains (Losses) on Investments Available-for-Sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(6,630)	687
Other comprehensive income before reclassification, net of tax	6,508	(9,368)
Reclassifications from accumulated other comprehensive income, net of tax	0	(47)
Current period change in other comprehensive income, net of tax	6,508	(9,415)
Reclassfication of tax effects from accumulated other comprehensive income		148
Ending Balance	(122)	(8,580)
Defined Benefit Pension Plan
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(9,124)	(7,544)
Other comprehensive income before reclassification, net of tax	0	0
Reclassifications from accumulated other comprehensive income, net of tax	196	131
Current period change in other comprehensive income, net of tax	196	131
Reclassfication of tax effects from accumulated other comprehensive income		(1,625)
Ending Balance	$ (8,928)	$ (9,038)