INCOME TAXES: (Details 2) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Other than temporary impairment	$ 753	$ 754
Net unrealized losses on retirement plans	8,132	7,465
Loan loss provisions	12,150	5,288
Deferred compensation	2,496	2,615
Compensated absences	623	611
Post-retirement benefits	1,286	1,309
Deferred loss on acquisition	0	482
Other	2,186	2,161
GROSS DEFERRED ASSETS	30,136	23,788
Deferred tax liabilities:
Net unrealized gains on securities available-for-sale	(8,752)	(4,248)
Depreciation	(2,155)	(2,376)
Mortgage servicing rights	(390)	(332)
Pensions	(843)	(475)
Intangibles	(5,458)	(3,285)
Other	(3,963)	(2,827)
GROSS DEFERRED LIABILITIES	(23,118)	(15,044)
NET DEFERRED TAX ASSETS (LIABILITIES)	$ 7,018	$ 8,744