Note 7 - Premises and Equipment - Premises and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, plant, and equipment, gross	$ 191,015	$ 188,821
Less: Accumulated depreciation/amortization	87,951	83,214
Premises and equipment, net	103,064	105,607
Land and Land Improvements [Member]
Property, plant, and equipment, gross	42,476	42,455
Building and Building Improvements [Member]
Property, plant, and equipment, gross	79,179	78,463
Furniture Fixtures and Equipment [Member]
Property, plant, and equipment, gross	53,529	51,654
Leasehold Improvements [Member]
Property, plant, and equipment, gross	15,496	15,546
Construction in Progress [Member]
Property, plant, and equipment, gross	$ 335	$ 703