INCOME TAXES: (Details 2) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets:
Other than temporary impairment	$ 5,417	$ 5,820
Net unrealized losses on retirement plans	16,068	6,815
Net unrealized losses on securities available for sale	0	2,701
Loan loss provisions	7,232	7,845
Deferred compensation	6,637	7,118
Compensated absences	894	857
Post-retirement benefits	2,014	2,045
Deferred loss on acquisition	1,377	929
Other	2,185us-gaap_DeferredTaxAssetsOther	2,771us-gaap_DeferredTaxAssetsOther
GROSS DEFERRED ASSETS	41,824us-gaap_DeferredTaxAssetsGross	36,901us-gaap_DeferredTaxAssetsGross
Deferred tax liabilities:
Net unrealized gains on securities available-for-sale	(5,831)	0
Depreciation	(2,423)	(2,528)
Mortgage servicing rights	(561)	(752)
Pensions	(2,182)	(1,818)
Intangibles	(1,652)	(1,086)
Other	(2,173)us-gaap_DeferredTaxLiabilitiesOther	(1,563)us-gaap_DeferredTaxLiabilitiesOther
GROSS DEFERRED LIABILITIES	(14,822)us-gaap_DeferredIncomeTaxLiabilities	(7,747)us-gaap_DeferredIncomeTaxLiabilities
NET DEFERRED TAX ASSETS (LIABILITIES)	$ 27,002us-gaap_DeferredTaxAssetsLiabilitiesNet	$ 29,154us-gaap_DeferredTaxAssetsLiabilitiesNet

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Amount of deferred tax liability attributable to taxable temporary differences from unrealized gains on trading securities.

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