OTHER COMPREHENSIVE INCOME (LOSS): (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance, January 1	$ (14,529)	$ (13,969)
Current Period Change	5,128	(560)
Ending balance, December 31	(9,401)	(14,529)
Unrealized Gains and Losses on Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance, January 1	10,278	(3,635)
Current Period Change	(1,225)	13,913
Ending balance, December 31	9,053	10,278
Unrealized gains losses on securities available-for-sale without other than temporary impairment
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance, January 1	7,164	(2,499)
Current Period Change	(1,081)	9,663
Ending balance, December 31	6,083	7,164
Unrealized gains losses on securities available-for-sale with other than temporary impairment
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance, January 1	3,114	(1,136)
Current Period Change	(144)	4,250
Ending balance, December 31	2,970	3,114
Retirement Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance, January 1	(24,807)	(10,334)
Current Period Change	6,353	14,473
Ending balance, December 31	$ (18,454)	$ (24,807)