PREMISES AND EQUIPMENT (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 214,886	$ 193,155
Accumulated depreciation	(100,452)	(99,522)
Premises and equipment, net	114,434	93,633
Land and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	22,191	17,722
Bank Premises [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	112,011	96,754
Equipment and Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 80,684	$ 78,679