ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS), Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance	$ 645,648	$ 596,758	$ 606,274	$ 602,081	$ 596,758	$ 602,081
Other comprehensive income (loss) before reclassifications					(7,368)	341
Amounts reclassified from accumulated other comprehensive loss					(1,095)	(129)
Other comprehensive income (loss), net of tax	(1,771)	(6,692)	(1,056)	1,268	(8,463)	212
Balance	681,543	645,648	608,701	606,274	681,543	608,701
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance	(12,632)	(5,940)	(5,232)	(6,500)	(5,940)	(6,500)
Other comprehensive income (loss), net of tax	(1,771)	(6,692)	(1,056)	1,268
Balance	(14,403)	(12,632)	(6,288)	(5,232)	(14,403)	(6,288)
Securities Available-for-Sale [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance		4,621		(1,957)	4,621	(1,957)
Other comprehensive income (loss) before reclassifications					9,609	5,981
Amounts reclassified from accumulated other comprehensive loss					(2,154)	89
Other comprehensive income (loss), net of tax					7,455	6,070
Balance	12,076		4,113		12,076	4,113
Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance		(6,024)		(6,290)	(6,024)	(6,290)
Other comprehensive income (loss) before reclassifications					241	250
Amounts reclassified from accumulated other comprehensive loss					130	245
Other comprehensive income (loss), net of tax					371	495
Balance	(5,653)		(5,795)		(5,653)	(5,795)
Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance		$ (4,537)		$ 1,747	(4,537)	1,747
Other comprehensive income (loss) before reclassifications					(17,218)	(5,890)
Amounts reclassified from accumulated other comprehensive loss					929	(463)
Other comprehensive income (loss), net of tax					(16,289)	(6,353)
Balance	$ (20,826)		$ (4,606)		$ (20,826)	$ (4,606)