PREMISES AND EQUIPMENT (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 219,775	$ 214,886
Accumulated depreciation	(107,457)	(100,452)
Premises and equipment, net	112,318	114,434
Land and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	22,585	22,191
Bank Premises [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	116,663	112,011
Equipment and Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 80,527	$ 80,684