OTHER COMPREHENSIVE INCOME (LOSS), Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	$ 565,868	$ 493,947
Other comprehensive income before reclassifications	207	18
Amounts reclassified from accumulated other comprehensive loss	218	234
Net other comprehensive income during the period	425	252
Balance	573,225	539,907
Accumulated Other Comprehensive Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(5,939)	(8,801)
Balance	(5,514)	(8,549)
Securities Held-to-Maturity and Transferred Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(713)	(760)
Other comprehensive income before reclassifications	18	10
Amounts reclassified from accumulated other comprehensive loss	0	0
Net other comprehensive income during the period	18	10
Balance	(695)	(750)
Securities Available-for-Sale [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(92)	(122)
Other comprehensive income before reclassifications	65	8
Amounts reclassified from accumulated other comprehensive loss	0	0
Net other comprehensive income during the period	65	8
Balance	(27)	(114)
Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(6,910)	(7,919)
Other comprehensive income before reclassifications	0
Amounts reclassified from accumulated other comprehensive loss	171	234
Net other comprehensive income during the period	171	234
Balance	(6,739)	(7,685)
Derivative Asset [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	1,776	0
Other comprehensive income before reclassifications	124	0
Amounts reclassified from accumulated other comprehensive loss	47	0
Net other comprehensive income during the period	171	0
Balance	$ 1,947	$ 0