INCOME TAXES: (Details 2) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Other than temporary impairment	$ 754	$ 761
Net unrealized losses on retirement plans	7,465	5,783
Net unrealized losses on securities available for sale	0	2,063
Loan loss provisions	5,288	5,463
Deferred compensation	2,615	2,883
Compensated absences	611	576
Post-retirement benefits	1,309	1,338
Deferred loss on acquisition	482	577
Other	2,161	2,140
GROSS DEFERRED ASSETS	23,788	21,584
Deferred tax liabilities:
Net unrealized gains on securities available-for-sale	(4,248)	0
Depreciation	(2,376)	(2,004)
Mortgage servicing rights	(332)	(319)
Pensions	(475)	(335)
Intangibles	(3,285)	(2,852)
Other	(2,827)	(2,614)
GROSS DEFERRED LIABILITIES	(15,044)	(8,124)
NET DEFERRED TAX ASSETS (LIABILITIES)	$ 8,744	$ 13,460