LOW INCOME HOUSING PROJECT INVESTMENTS Low Income Housing Project Investments (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Tax Expense related to a change in tax law	$ 2,361,000	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 466,000		$ 0	$ 0
Original Investment in Low Income Housing Projects	47,399,000				47,379,000				47,399,000		47,379,000	42,199,000
Amortization Method Qualified Affordable Housing Project Investments	35,225,000				39,606,000				35,225,000		39,606,000	38,151,000
Qualified Affordable Housing Project Investments, Commitment	4,536,000				$ 12,161,000				4,536,000		12,161,000	14,607,000
Affordable Housing Tax Credits and Other Tax Benefits, Amount									5,654,000		5,366,000	3,632,000
Amortization Method Qualified Affordable Housing Project Investments, Amortization									4,402,000	[1]	3,725,000	2,450,000
Income (Loss) from Affordable Housing Projects, Equity Method Investments									1,253,000		$ 1,641,000	$ 1,182,000
Investments in Low Income Housing Projects [Member]
Tax Expense related to a change in tax law	$ 466,000								$ 466,000

[1] The 2017 amount is inclusive of $466,000 related to the revaluation of Low Income Housing tax credit investments as a result of the 2017 Tax Act.