Loans and Allowance for Credit Losses Non-Performing Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Receivables [Abstract]
Non-accrual loans	$ 120,133	$ 129,523
Loans 90 days or more past due and still accruing	11,505	15,291
Total non-performing loans	131,638	144,814
Other real estate owned	12,815	11,099
Total non-performing assets	$ 144,453	$ 155,913