OTHER COMPREHENSIVE INCOME (LOSS)-AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance, January 1	$ (9,401)	$ (14,529)
Change in other comprehensive income before reclassification	(5,958)	219
Amounts reclassified from accumulated other comprehensive income	1,195	4,909
Net current period other comprehensive income (loss)	(4,763)	5,128
Ending balance, December 31	(14,164)	(9,401)
Unrealized Gains and Losses on Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance, January 1	9,053	10,278
Change in other comprehensive income before reclassification	(10,109)	(1,214)
Amounts reclassified from accumulated other comprehensive income	(21)	(11)
Net current period other comprehensive income (loss)	(10,130)	(1,225)
Ending balance, December 31	(1,077)	9,053
Retirement Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance, January 1	(18,454)	(24,807)
Change in other comprehensive income before reclassification	4,151	1,433
Amounts reclassified from accumulated other comprehensive income	1,216	4,920
Net current period other comprehensive income (loss)	5,367	6,353
Ending balance, December 31	$ (13,087)	$ (18,454)