INCOME TAXES: (Details 2) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Other than temporary impairment	$ 5,397	$ 5,411
Net unrealized losses on retirement plans	8,576	12,007
Net unrealized losses on securities available for sale	719	0
Loan loss provisions	7,318	7,755
Deferred compensation	5,881	6,257
Compensated absences	832	917
Post-retirement benefits	2,043	2,026
Deferred loss on acquisition	1,111	1,177
Other	3,119	2,887
GROSS DEFERRED ASSETS	34,996	38,437
Deferred tax liabilities:
Net unrealized gains on securities available-for-sale	0	(5,234)
Depreciation	(2,778)	(2,632)
Mortgage servicing rights	(486)	(539)
Pensions	(65)	(424)
Intangibles	(3,015)	(2,283)
Other	(3,180)	(2,863)
GROSS DEFERRED LIABILITIES	(9,524)	(13,975)
NET DEFERRED TAX ASSETS (LIABILITIES)	$ 25,472	$ 24,462