OTHER COMPREHENSIVE INCOME (LOSS): (Details 1) - 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)
Current Period Change	(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
Current Period Change	(10,130)	(1,225)
Ending balance, December 31	(1,077)	9,053
Unrealized gains losses on securities available-for-sale without other than temporary impairment
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance, January 1	5,855	7,164
Current Period Change	(8,873)	(1,309)
Ending balance, December 31	(3,018)	5,855
Unrealized gains losses on securities available-for-sale with other than temporary impairment
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance, January 1	3,198	3,114
Current Period Change	(1,257)	84
Ending balance, December 31	1,941	3,198
Retirement Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance, January 1	(18,454)	(24,807)
Current Period Change	5,367	(6,353)
Ending balance, December 31	$ (13,087)	$ (18,454)