Accrued Interest and Other Assets (Other assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other asset
Other prepaid expenses	$ 9,200	$ 16,501
Other repossessed assets	3,548	3,224
Core deposit intangible and customer relationship intangibles	4,687	6,160
Mortgage tax credits	4,277	6,277
Investment in Statutory Trust	1,083	1,083
Accounts receivable and other assets	41,898	47,120
Other assets	$ 64,693	$ 80,365