INCOME TAXES: (Details 2) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Other than temporary impairment	$ 1,829	$ 5,397
Net unrealized losses on retirement plans	6,609	8,576
Net unrealized losses on securities available for sale	0	719
Loan loss provisions	5,195	7,318
Deferred compensation	3,661	5,881
Compensated absences	563	832
Post-retirement benefits	1,359	2,043
Deferred loss on acquisition	663	1,111
Other	2,123	3,119
GROSS DEFERRED ASSETS	22,002	34,996
Deferred tax liabilities:
Net unrealized gains on securities available-for-sale	(804)	0
Depreciation	(1,989)	(2,778)
Mortgage servicing rights	(308)	(486)
Pensions	(201)	(65)
Intangibles	(2,446)	(3,015)
Other	(2,408)	(3,180)
GROSS DEFERRED LIABILITIES	(8,156)	(9,524)
NET DEFERRED TAX ASSETS (LIABILITIES)	$ 13,846	$ 25,472