Loans and Allowance for Credit Losses Non-Performing Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Receivables [Abstract]
Non-accrual loans	$ 122,170	$ 129,523
Loans 90 days or more past due and still accruing	15,013	15,291
Total non-performing loans	137,183	144,814
Other real estate owned (OREO)	10,946	11,099
Total non-performing assets	$ 148,129	$ 155,913