MORTGAGE BANKING AND LOAN SERVICING -Mortgage Servicing Assets and Valuation Allowance - (Details) - Mortgage servicing rights - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Mortgage servicing assets and interest rate locks
Balance at the beginning of the period	$ 6,120	$ 5,708	$ 5,155
Servicing assets capitalized	1,636	1,525	988
Servicing rights acquired	1,164		594
Amortization of servicing assets	(1,510)	(1,313)	(1,004)
Change in valuation allowance		200	(25)
Balance at the end of the period	7,410	6,120	5,708
Valuation allowance:
Balance at the beginning of the period	200	400	375
Additions expensed	175	25	75
Reductions credited to operations	(175)	(225)	(50)
Balance at the end of the period	$ 200	$ 200	$ 400