Loans and Allowance for Credit Losses Non-Performing Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Receivables [Abstract]
Non-accrual loans	$ 129,523	$ 121,080
Loans 90 days or more past due and still accruing	15,291	17,402
Total non-performing loans	144,814	138,482
Other real estate owned	11,099	12,022
Total non-performing assets	$ 155,913	$ 150,504