GOODWILL AND INTANGIBLE ASSETS - Intangible assets (Details) - USD ($) $ in Thousands		12 Months Ended
	Nov. 10, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite-lived intangible assets
Gross Carrying Amount		$ 26,013	$ 23,683
Accumulated Amortization		(18,826)	(16,679)
Total		7,187	7,004
Amortization of intangible assets		2,147	2,460	$ 2,115
Intangibles	$ 2,300
Estimated amortization expense of intangible assets
2017		1,827
2018		1,247
2019		913
2020		597
2021		446
Thereafter		2,157
Total		7,187	7,004
Core deposits
Finite-lived intangible assets
Gross Carrying Amount		20,542	20,542
Accumulated Amortization		(16,181)	(14,471)
Total		4,361	6,071
Estimated amortization expense of intangible assets
Total		4,361	6,071
Customer relationship
Finite-lived intangible assets
Gross Carrying Amount		5,471	3,141
Accumulated Amortization		(2,645)	(2,208)
Total		2,826	933
Estimated amortization expense of intangible assets
Total		$ 2,826	$ 933
Sterling
Finite-lived intangible assets
Intangibles	$ 2,300
Amortization period	20 years