ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Net Accumulated Other Comprehensive Income (Loss)) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			$ (6,857)	$ (6,614)
Other comprehensive income before reclassification, net of tax			(16,479)	3,382
Reclassifications from accumulated other comprehensive income, net of tax			393	(245)
Current period change in other comprehensive income, net of tax	$ (3,864)	$ 235	(16,086)	3,137
Reclassfication of tax effects from accumulated other comprehensive income			(1,477)
Ending Balance	(24,420)	(3,477)	(24,420)	(3,477)
Unrealized Gains (Losses) on Investments Available-for-Sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			687	1,642
Other comprehensive income before reclassification, net of tax			(16,479)	3,382
Reclassifications from accumulated other comprehensive income, net of tax			(107)	(767)
Current period change in other comprehensive income, net of tax			(16,586)	2,615
Reclassfication of tax effects from accumulated other comprehensive income			148
Ending Balance	(15,751)	4,257	(15,751)	4,257
Defined Benefit Pension Plan
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(7,544)	(8,256)
Other comprehensive income before reclassification, net of tax			0	0
Reclassifications from accumulated other comprehensive income, net of tax			500	522
Current period change in other comprehensive income, net of tax			500	522
Reclassfication of tax effects from accumulated other comprehensive income			(1,625)
Ending Balance	$ (8,669)	$ (7,734)	$ (8,669)	$ (7,734)