Bank Premises and Equipment Net Book Value (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Bank Premises and Equipment
Total bank premises and equipment	$ 96,070	$ 78,337
Accumulated depreciation	(42,583)	(38,002)
Bank premises and equipment, net	53,487	40,335
Land
Bank Premises and Equipment
Total bank premises and equipment	11,976	7,612
Building and premises
Bank Premises and Equipment
Total bank premises and equipment	58,607	48,402
Furniture, fixtures and equipment
Bank Premises and Equipment
Total bank premises and equipment	$ 25,487	$ 22,323