OTHER COMPREHENSIVE INCOME (LOSS): (Details 1) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance, January 1	$ (23,454)	$ (14,704)
Current Period Change	15,953	(8,750)
Ending balance, December 31	(7,501)	(23,454)
Unrealized Gains and Losses on Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance, January 1	(6,105)	2,258
Current Period Change	20,998	(8,363)
Ending balance, December 31	14,893	(6,105)
Unrealized gains losses on securities available-for-sale without other than temporary impairment
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance, January 1	(8,446)	(1,371)
Current Period Change	20,624	(7,075)
Ending balance, December 31	12,178	(8,446)
Unrealized gains losses on securities available-for-sale with other than temporary impairment
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance, January 1	2,341	3,629
Current Period Change	374	(1,288)
Ending balance, December 31	2,715	2,341
Retirement Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance, January 1	(17,349)	(16,962)
Current Period Change	(5,045)	387
Ending balance, December 31	$ (22,394)	$ (17,349)

Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e637-108580

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14A
-URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669686-108580

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e681-108580

Name:	us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant